A10 - ACCEPTABLE CONDITIONS
A10-1 General requirements - Work responsibilities for Moisture Testing, Flatness, Contaminants Removal, Indoor Environmental Conditions.
A10-2 Selective demolition or alteration / renovation work
A10-3 Moisture and Alkalinity - Test methods
A10-4 Concrete - Flatness / Level / Placing / Curing
A10-5 Testing of substrates
A10-6 Concrete substrates
A10-7 Wooden substrates
A10-8 Substrates with existing resilient flooring
A10-9 Substrates with other existing floor covering types
A10-10 Asbestos containing flooring materials
A10-11 Liquid adhesive removers
A10-12 Painted or coated substrates
A10-13 Metal substrates
A10-14 Radiant heated substrates
A10-15 Primers on substrates
A10-16 Substrate protection
A10-17 Installation requirements
A10-18 interior hoarding
A10-19 Vapor Retarders
A10-2 Selective demolition or alteration / renovation work
A10-3 Moisture and Alkalinity - Test methods
A10-4 Concrete - Flatness / Level / Placing / Curing
A10-5 Testing of substrates
A10-6 Concrete substrates
A10-7 Wooden substrates
A10-8 Substrates with existing resilient flooring
A10-9 Substrates with other existing floor covering types
A10-10 Asbestos containing flooring materials
A10-11 Liquid adhesive removers
A10-12 Painted or coated substrates
A10-13 Metal substrates
A10-14 Radiant heated substrates
A10-15 Primers on substrates
A10-16 Substrate protection
A10-17 Installation requirements
A10-18 interior hoarding
A10-19 Vapor Retarders
Preface:
This reference guide covers acceptable conditions including substrate surface requirements for floor covering work included in the NFCA Reference Manual. Individuals using this guide should verify all site conditions and manufacturers requirements relative to the particular project.
Note: For clarification purposes the term Contractor or Constructor used herein will mean the "General Contractor" or "Prime Contractor", depending on the type of contract used and unless otherwise defined by the General or Supplementary Conditions of the Contract. For instance, where the work is done under a construction management contract, the term "Contractor" shall mean the "Construction Manager" and where flooring work is done directly under contract with an Owner (as in a renovation), the term "Contractor" shall mean the flooring contractor. In the later case, the Owner is to provide acceptable surfaces and conditions unless otherwise mutually agreed to between both parties.
1 • GENERAL REQUIREMENTS
.01 All substrate surfaces to receive flooring materials included within this Reference Manual shall be in strict accordance with NFCA requirements noted herein and with NFCA Quality Assurance Program requirements when applicable.
.02 In addition, all such substrate surfaces shall be in accordance with the floor covering material manufacturer's recommendations. Where any conflict occurs between NFCA and manufacturer's requirements, this shall be rectified by contacting either NFCA or the applicable provincial floor covering association and the product manufacturer for clarification.
.03 The design authority must verify the required substrate conditions with the floor covering material manufacturer and NFCA and specify the appropriate requirements.
.04 Each new and existing substrate surface shall be inspected to determine its suitability for the application of resilient, carpet, hardwood, laminate, or other flooring materials included in the Reference Manual and for those materials and methods required to provide an acceptable surface.
.05 All substrate surfaces will be free of cracks and protrusions and be structurally sound, stable and deflection free unless the cracks and protrusions and the deflection limit of the flooring system are within the limits acceptable to the manufacturer of the materials being installed.
.06 NFCA describes requirements for third‑party inspection of substrate surfaces for flatness, moisture content, porosity and alkalinity as a prerequisite to scheduling any floor covering work.
Note: The existing subfloor/substrate should be "sound and stable" without the risk of debonding or delamination of the concrete or any added leveller, or skimcoat that could affect the floor covering and its performance. Furthemore, during early renovation construction, if the subfloor/substrate is found to be sound and stable (i.e. using visual observations, sounding bar, hammer strikes, chain drag, chipping tests, shot blasting, and/or other evaluation methods) then it should be protected from static and dynamic loads as well as accidental impact damage during on-going construction. This may require the use of hardboard or plywood of sufficient thickness to protect the subfloor/substrate from potential fracturing, cracking, delamination, and/or shear damage.
"Sound" would refer to the subfloor/substrate being of sufficient integrity, hardness, rigidity, and internal cohesive (i.e. not powdery or flaking) strength to withstand future use activities.
"Stable" would refer to the subfloor/substrate's ability to perform without any potential adverse reaction causing delamination, fracturing, or cracking while the floor covering is in service.
.07 The Contractor will provide substrate surfaces that are smooth (for concrete see Concrete Surface profile, CSP chart), flat (to minimum industry standards), level, thoroughly dry, and free from alkali, laitance, dust, dirt, adhesives, paint, varnish, solvents, oils and grease, waxes, release agents, sealers and curing and hardening compounds that are incompatible with adhesives and other flooring materials to be used or that are unacceptable or detrimental to the application requirements of selected flooring materials.
.08 The Contractor will provide substrates within moisture and alkalinity levels acceptable for floor covering materials. Testing for moisture and alkalinity shall be done by an independent third party agency provided and paid for by the Contractor or Owner in a timely manner. Test results must confirm acceptable conditions within manufacturer's moisture and alkalinity limits before commencement of any flooring work.
.09 The Contractor will provide substrate surface level and flatness conditions that meet the tolerances required by the floor covering material manufacturer and/or as published in the latest edition of ASTM F-710. This includes grinding or sanding of ridges, undulations, projections, and areas of carbonation, laitance, scaling and filling and leveling of expansion joints, cracks, grooves and other irregularities. Where patching or leveling is required, the use of a Latex base-filling compound is recommended. Vacuum floor surfaces to remove dust and debris, and other contaminants that affect bonding of patching and leveling compounds.
.10 Acceptable subfloor flatness (surface undulation) that meets manufacturers tolerance shall be confirmed prior to installation start up. Subfloor flatness testing using surface mapping technology or 10' (3m) straightedge method must be performed and test results verified: It shall be the responsibility of the Contractor to provide and pay for such testing in a timely manner. The floor covering contractor shall verify test results.
Note: FF/FL test method when performed according to ASTM E1155 is not an acceptable measurement method to determine acceptable substrate flatness for installation of floor coverings.
.11 Confirm that substrate surfaces are acceptable for installation of flooring materials as follows:
This reference guide covers acceptable conditions including substrate surface requirements for floor covering work included in the NFCA Reference Manual. Individuals using this guide should verify all site conditions and manufacturers requirements relative to the particular project.
Note: For clarification purposes the term Contractor or Constructor used herein will mean the "General Contractor" or "Prime Contractor", depending on the type of contract used and unless otherwise defined by the General or Supplementary Conditions of the Contract. For instance, where the work is done under a construction management contract, the term "Contractor" shall mean the "Construction Manager" and where flooring work is done directly under contract with an Owner (as in a renovation), the term "Contractor" shall mean the flooring contractor. In the later case, the Owner is to provide acceptable surfaces and conditions unless otherwise mutually agreed to between both parties.
1 • GENERAL REQUIREMENTS
.01 All substrate surfaces to receive flooring materials included within this Reference Manual shall be in strict accordance with NFCA requirements noted herein and with NFCA Quality Assurance Program requirements when applicable.
.02 In addition, all such substrate surfaces shall be in accordance with the floor covering material manufacturer's recommendations. Where any conflict occurs between NFCA and manufacturer's requirements, this shall be rectified by contacting either NFCA or the applicable provincial floor covering association and the product manufacturer for clarification.
.03 The design authority must verify the required substrate conditions with the floor covering material manufacturer and NFCA and specify the appropriate requirements.
.04 Each new and existing substrate surface shall be inspected to determine its suitability for the application of resilient, carpet, hardwood, laminate, or other flooring materials included in the Reference Manual and for those materials and methods required to provide an acceptable surface.
.05 All substrate surfaces will be free of cracks and protrusions and be structurally sound, stable and deflection free unless the cracks and protrusions and the deflection limit of the flooring system are within the limits acceptable to the manufacturer of the materials being installed.
.06 NFCA describes requirements for third‑party inspection of substrate surfaces for flatness, moisture content, porosity and alkalinity as a prerequisite to scheduling any floor covering work.
- The Floor Covering Contractor is not responsible for third‑party testing of new or existing concrete slabs, on grade or elevated (suspended).
- Tests areas that do not pass manufacturer or NFCA standards shall be corrected and re-tested in a timely manner.
- The Floor Covering Contractor shall not be responsible for delays related to delayed testing, testing results or site conditions that do meet manufacturers or NFCA standards.
Note: The existing subfloor/substrate should be "sound and stable" without the risk of debonding or delamination of the concrete or any added leveller, or skimcoat that could affect the floor covering and its performance. Furthemore, during early renovation construction, if the subfloor/substrate is found to be sound and stable (i.e. using visual observations, sounding bar, hammer strikes, chain drag, chipping tests, shot blasting, and/or other evaluation methods) then it should be protected from static and dynamic loads as well as accidental impact damage during on-going construction. This may require the use of hardboard or plywood of sufficient thickness to protect the subfloor/substrate from potential fracturing, cracking, delamination, and/or shear damage.
"Sound" would refer to the subfloor/substrate being of sufficient integrity, hardness, rigidity, and internal cohesive (i.e. not powdery or flaking) strength to withstand future use activities.
"Stable" would refer to the subfloor/substrate's ability to perform without any potential adverse reaction causing delamination, fracturing, or cracking while the floor covering is in service.
.07 The Contractor will provide substrate surfaces that are smooth (for concrete see Concrete Surface profile, CSP chart), flat (to minimum industry standards), level, thoroughly dry, and free from alkali, laitance, dust, dirt, adhesives, paint, varnish, solvents, oils and grease, waxes, release agents, sealers and curing and hardening compounds that are incompatible with adhesives and other flooring materials to be used or that are unacceptable or detrimental to the application requirements of selected flooring materials.
.08 The Contractor will provide substrates within moisture and alkalinity levels acceptable for floor covering materials. Testing for moisture and alkalinity shall be done by an independent third party agency provided and paid for by the Contractor or Owner in a timely manner. Test results must confirm acceptable conditions within manufacturer's moisture and alkalinity limits before commencement of any flooring work.
.09 The Contractor will provide substrate surface level and flatness conditions that meet the tolerances required by the floor covering material manufacturer and/or as published in the latest edition of ASTM F-710. This includes grinding or sanding of ridges, undulations, projections, and areas of carbonation, laitance, scaling and filling and leveling of expansion joints, cracks, grooves and other irregularities. Where patching or leveling is required, the use of a Latex base-filling compound is recommended. Vacuum floor surfaces to remove dust and debris, and other contaminants that affect bonding of patching and leveling compounds.
.10 Acceptable subfloor flatness (surface undulation) that meets manufacturers tolerance shall be confirmed prior to installation start up. Subfloor flatness testing using surface mapping technology or 10' (3m) straightedge method must be performed and test results verified: It shall be the responsibility of the Contractor to provide and pay for such testing in a timely manner. The floor covering contractor shall verify test results.
Note: FF/FL test method when performed according to ASTM E1155 is not an acceptable measurement method to determine acceptable substrate flatness for installation of floor coverings.
.11 Confirm that substrate surfaces are acceptable for installation of flooring materials as follows:
.1 Coordination of substrate design and specification requirements with floor covering material manufacturer's installation requirements. This will also entail the coordination of such requirements between Consultant specifications, notably Architectural, Structural, and Mechanical for such things as substrate reinforcement, loads, and deflection, levels and flatness, finishes, joints, drains, etc.
.2 Before commencement of work on site (i.e., before construction start-up), the Contractor, flooring contractor, flooring manufacturer's factory / distributor representatives and the Consultant will meet to discuss the following items:
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.12 The construction community accepts the need for independent testing for a variety of validation and verification requirements associated with quality control and quality
assurance.
assurance.
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.13 The Contractor (the general contractor, construction manager or design‑builder) is responsible for engaging with and paying for third‑party testing of substrate surfaces, and
correcting them to meet NFCA requirements for flatness, moisture content, porosity and alkalinity as a part of the Constructor’s QC/QA program.
correcting them to meet NFCA requirements for flatness, moisture content, porosity and alkalinity as a part of the Constructor’s QC/QA program.
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.14 The Contractor shall provide indoor environmental conditions (air flow, heat and relative humidity) in strict accordance with manufacturers requirements for the floor covering and all related products (adhesive, cement underlayment etc). These conditions shall be maintained within the specified range before, during and after installation.
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2 • SELECTIVE DEMOLITION OR ALTERATION / RENOVATION WORK
.01 Unless otherwise specified or agreed to prior to commencing work, the Contractor will be responsible for the removal of all existing floor coverings including adhesives, cushion, accessories, and bases in areas scheduled to receive replacement flooring, and for the subsequent required subfloor restoration / preparation work.
.02 This Work shall include:
.01 Unless otherwise specified or agreed to prior to commencing work, the Contractor will be responsible for the removal of all existing floor coverings including adhesives, cushion, accessories, and bases in areas scheduled to receive replacement flooring, and for the subsequent required subfloor restoration / preparation work.
.02 This Work shall include:
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3 • MOISTURE AND ALKALINITY
.01 Moisture Content of Substrates:
.01 Moisture Content of Substrates:
.1 All concrete substrates will be tested for moisture content after the concrete has cured and before the application of any flooring materials.
.2 All wood substrates (i.e. floor sheathing) that were installed wet or that have been exposed to the elements before closing in the area will be tested for moisture content before the application of any flooring materials.
.3 At the scheduled time of floor covering installation, the moisture content of any substrate must not exceed the floor covering manufacturers recommendation for the products specified.
.4 There are a number of "testing" methods that are used to determine if moisture is present in concrete. These tests fall into two categories:
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NFCA does not consider that indicator tests are adequate enough to determine the amount of moisture present and requires that more definitive moisture testing be done. For a detailed explanation of such tests refer to Part A11 – Substrate Testing.
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NOTE:
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It shall be the responsibility of the Contractor or Owner or his agent to provide adequate and definitive "moisture testing" and alkalinity testing by an independent agency in a timely manner in accordance with NFCA requirements. Results shall be acceptable to the floor covering manufacturer for products specified before the installation of any flooring material commences.
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.5 Where moisture, hydrostatic pressure, or alkaline conditions exist or persist, the installation of any floor coverings is not recommended.
Installation or product failures due to excessive amounts of moisture or alkali in substrates are not the responsibility of the flooring manufacturer, supplier, or floor covering contractor.
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.6 Alkaline Levels in Concrete Substrates
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.02 Vapour Retarder / Moisture Barrier Requirements:
.1 To prevent moisture migration up through concrete substrates located on and below grade and damage to installed floor coverings, the concrete slab shall be protected from ground moisture and hydrostatic pressure by the use of an industry approved vapour retarder / moisture barrier or waterproof membrane having a permeance of less than 0.3 perms (0.2 metric perms) in accordance with ASTM E-96. The barrier / membrane shall be installed continuously under the slab and over a minimum 100 to 150 mm (4" to 6") of compacted free draining granular material in accordance with local Building Code requirements and to recommendations of a Geotechnical Consultant if and when applicable.
.2 The water vapor retarder under the slab must have a lower degree of permeance than the scheduled floor covering above the slab. If it doesn’t, a moisture imbalance could eventually cause hydraulic cement underlayment, flooring adhesive and/or floor covering failure. ASTM International gives specific guidelines in ASTM E1745, ASTM E1643 and ASTM F710 for the use, installation, and inspection of vapor barriers used under concrete slabs.
.3 The water vapour retarder / moisture barrier or waterproof membrane must be properly installed, taped, and sealed to prevent the passage of liquid water under hydrostatic pressure or the passage of water vapour by capillary action (wicking).
.03 Moisture Problems in Concrete Substrates:
.1 Where excess moisture is evident in new or existing concrete substrates it may be attributed to a number reasons:
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.04 Dew Point (Surface condensation)
.1 Avoid conditions where dew point allows for the condensing of moisture on concrete substrates. The substrate must be at least 5°F above dew point to be considered acceptable.
Example: If the ambient conditions are 70°F and 65% RH, the dew point is 57°F, you must not proceed with the installation. The surface temperature must be a minimum of 62°F.
Example: If the ambient conditions are 70°F and 65% RH, the dew point is 57°F, you must not proceed with the installation. The surface temperature must be a minimum of 62°F.
Dew point calculation charts and calculators are available on the internet. Example click here.
.05 Due to the sensitivity of some flooring types to moisture or alkalinity, all concrete floors shall be tested. Floor covering work shall not commence where there is an indication of moisture or hydrostatic pressure or excess alkalinity.
Example of moisture related flooring problems.
4 • CONCRETE (Division 3)
.01 Concrete substrates for floor finishes shall conform to the following general requirements
.02 Granular Fill Requirements:
.03 Concrete Formwork Requirements: (suspended concrete slabs)
.04 Concrete Quality:
.05 Lightweight and Cellular Concrete:
.06 Concrete Classifications: Both new and existing concrete substrates (or subfloors) can be grouped into three general classifications:
.07 Concrete Handling, Placing, and Finishing:
.01 Concrete substrates for floor finishes shall conform to the following general requirements
.02 Granular Fill Requirements:
- The thickness, compaction, and level of granular fill for concrete slabs-on-grade is critical for flooring finishes on concrete. In accordance with CSA A23.1 the maximum elevation variation of a compacted granular base is + 10 mm (3/8") and the average thickness of concrete may be 10 mm (3/8") less that that specified with a maximum local variation of 20 mm (3/4"). In the worst case this may result in concrete slab thickness below allowable limits that may lead to future problems. Fill levels must be set using a laser level and surfaces must be inspected and any deficiencies in thickness, levels, and compaction rate corrected before concrete is placed.
.03 Concrete Formwork Requirements: (suspended concrete slabs)
- All suspended concrete formwork shall be designed to accommodate slab deflection under dead load and long-term sag between supports in accordance with Building Code load and deflection requirements and to provide a smooth, flat, level, and structurally sound system free of vertical movement detrimental to flooring materials installed. In some instances formwork may be cambered to accommodate deflection and sag after formwork is removed.
.04 Concrete Quality:
- Unless concrete quality control measures are observed, including those dealing with workability of materials, ambient conditions, and method and quality of screeding operations to an accurate bench mark and level, undesirable properties in the hardened concrete may occur - particularly at the wearing surface - which may lead to a soft or dusting surface, permeable concrete, cracking or poor durability.
- All materials used in concrete shall conform to current / applicable CSA and/or ASTM requirements established for cement type, aggregate size, mix design, and end-use of concrete.
- Unless otherwise required, concrete should be of standard density, with a low water / cement ratio consistent with placing and finishing requirements in accordance with applicable CSA or ASTM requirements for interior slab finishes and levels.
- Even if the above noted requirements are adhered to the quality of concrete is still dependent on the use of skilled concrete installers / finishers using appropriate equipment.
.05 Lightweight and Cellular Concrete:
- Lightweight and cellular concrete substrates with a density of less than 1600 kg / m3 (100 lbs/ft3.), have generally such low surface strength that they are unable to support common on-site used static or rolling loads and are therefore, considered unsuitable for the direct installation of resilient flooring, unless 25 mm (1") or more of Standard Concrete is used as a topping.
- Lightweight concrete substrates must have a minimum density of 1600 kg/m3 (100 lbs/ft3) and a minimum compressive strength of 3500 psi or greater to be acceptable for regular traffic use.
.06 Concrete Classifications: Both new and existing concrete substrates (or subfloors) can be grouped into three general classifications:
- Below Grade Concrete Substrates: concrete substrates in contact with earth or fill and below ground level.
- On Grade Concrete Substrates: concrete substrates in contact with earth or fill, but not below the ground level at any point. In all other cases, substrates in contact with the earth at/or above ground level are to be considered as on grade type substrates.
- Suspended Concrete Substrates: concrete substrates having no contact with earth or fill.
.07 Concrete Handling, Placing, and Finishing:
- All concrete handling and placing operations shall be such as to eliminate the possibility of segregation of aggregate and cement fines.
- Concrete finishing operations should be performed with care. The following placing and finishing methods are used:
- Consolidation: this operation is performed immediately after the concrete is placed to compact and mould concrete within the forms and around embedded items and reinforcement and to eliminate stone pockets, honeycombing, and entrapped air. Vibration, either internal or external, is the most widely used method for consolidating concrete. When concrete is vibrated, the internal friction between the aggregate particles is temporarily eliminated resulting in the concrete behaving like a liquid settling it into forms by gravity and large entrapped air voids rising more easily to the surface.
- Screeding or strike off: this operation is performed immediately after the concrete is placed to remove excess concrete and to roughly level the surface. Concrete must be screeded to an established benchmark and levels checked using laser levels.
- Darbying: this operation using a stiff wood or metal straight edge is used to embed surface aggregates and eliminate ridges and voids left by screeding.
- Floating: this operation using a bull or hand float is performed after the water sheen disappears off the placed concrete and the concrete is set enough to support the weight of a person to further embed coarse aggregate, to remove slight surface imperfections left by edging and jointing, and to consolidate / compact cement mortar at the surface.
- Trowelling: this operation using hand or power operated equipment is used to provide a smooth finish to concrete surfaces within level and smoothness tolerances noted in the applicable standards or particularly specified for the type of floor finish to be applied. Surfaces should be hand or power floated before any trowelling operation is performed. If necessary, tooled joints and edges should be rerun before and after trowelling to maintain true lines and depths. Time should be allowed between successive trowelling operations to permit the concrete to become harder. As the surface stiffens, each trowelling operation should be made with successively smaller trowels tipped at progressively higher angles so that sufficient pressure can be applied for proper finishing.
- Concrete Surface Profiles (CSP) quantify acceptable concrete surfaces for adhesives, floor covering products and Hydraulic Cement Underlayment. CSP charts (see Figure 1) and sample swatches are available for this purpose. A surface requirement of CSP 3 for most Hydraulic Cement Underlayment products and a CSP of 2 for most resilient flooring products. Refer to manufacturers own installation guidelines for their individual product requirements.
- Surface smoothness can be improved by additional trowelling. For exposed slabs, additional troweling increases the compaction of fines at the surface, giving greater density and better wear resistance. Over troweling however, can create an overly smooth, dense concrete surface that can slow Moisture Vapour Emission Rate, extending concrete drying times. The surface should not be left overly smooth, or burnished.
- Concrete with a 15% or greater flysh content: Concrete substrates with 15% or higher flyash content can present an overly dense (non porous) surface when finish/power troweled. It is important to ensure a smooth but textured concrete surface that facilitates mechanical adhesion exists before installation proceeds. Therefore, super smooth concrete surfaces should be shot blasted (or grinded) to create texture and a profile that can be lightly skim coated. Conduct a bond test to confirm adhesive (and / or cementitious underlayment) compatibility with concrete surface preparation before installation proceeds.
- Excess water should not be left on the surface, as it will cause dusting, crazing, and scaling.
- While slight imperfections may be hidden by a carpet's texture or backing, by carpet cushion or a flooring underlayment, or by hard flooring (hardwood, laminate, bamboo, etc.), any slab imperfection, including minor waviness, hairline cracks, and even sand particles inadvertently left on the surface, will telegraph or show through most resilient floor coverings particularly those with high gloss finishes. It is therefore imperative, that concrete surfaces be carefully reviewed for imperfections and that such surfaces are correctly prepared and thoroughly cleaned and vacuumed before the application of any floor covering materials
- Unless otherwise required by the floor covering material manufacturer, all concrete substrates (including acceptable lightweight or cellular concrete surfaces) shall be steel trowelled to a smooth, dense, level, and even finish.
.08 Concrete Flatness/Levels:
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- There are a number of methods used to specify concrete "flatness" and 'level' tolerances to guide placement and finishing of new concrete slabs which are endorsed by the Cement Association of Canada (CAC) (formerly the Canadian Portland Cement Association) and by the American Concrete Institute in publications ACI 117 and ACI 302.1R.
- Two main Consensus Standard organizations define these methods:
- The Canadian Standards Association (CSA) provides three options in CAN/CSA A23.1, Concrete Materials and Methods of Concrete Construction, namely: the Straightedge Method, the Waviness Method based on ASTM E1486, and the F-Number Method based on ASTM E1155.
- The ASTM International provides two different test methods, namely: ASTM E1486, Standard Test Method for Determining Floor Tolerances Using Waviness, Wheel Path and Levelness Criteria, and ASTM E1155, Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers.
- There are three methods used to define / measure level tolerances:
- Straightedge Method: Random measurements of one per 10 m² (107 ft²) are taken using a 3000 mm (10 ft) metal straightedge placed parallel and then at right angles to the long direction of the substrate surface. Measurements shall be to the closest 1 mm and compliance is considered satisfactory if 90% of the measurements are less than or equal to the specified method's designated Class tolerance, i.e., "Straightedge Values" of CSA A23.1 Table 19 – Slab and Floor Finish Classifications.
- This measurement method however has at times resulted in some disagreement as to what is really meant. Does 1/8th inch in ten feet mean ±1/8" in 120" (a horizontal 1/4" envelope which is 10' long) or does it mean ±1/16" in 120" (a horizontal 1/8" envelope which is 10' long)? As there is no standard for either the test method or for interpreting the results no two individuals will get the same results. These straightedge measurements do not control the characteristics of the floor that relate to its usefulness. For instance, all of the following floor profiles would satisfy the 1/8th inch in ten feet measurement criteria:
A more accurate measurement system is required.
- Waviness Method: Measurements for each area are taken in accordance with ASTM E1486 requirements along surveyed transverse and longitudinal lines of the substrate surface and waviness deviations are calculated and analyzed. Compliance is considered satisfactory if the Surface Waviness Index (SWI) of the entire floor area is less than or equal to the specified method's designated Class value (e.g. "Surface Waviness Index" of CSA A23.1 Table 19 - Slab and Floor Finish Classifications).
- F-Number Method: This measurement method measures deviations of floor flatness (FF) and floor levelness (FL). Floor flatness relates to the bumpiness of the floor, while floor levelness relates to the tilt or pitch of the floor. The higher the F-Number, the better that characteristic of the floor. F-Numbers are linear, so an FF 20 is twice as flat as an FF 10, but only half as flat as an FF 40. Slabs-on-grade are usually specified with an FF number and an FL number (the FF is always listed first), such as: FF 25 / FL20. Because of deflection, elevated slabs are usually specified using FF only. When a floor is described as an "F 25", it usually means "FF 25".
- Note: FF/FL test method when performed according to ASTM E1155 is not an acceptable measurement method to determine acceptable substrate flatness for floor coverings.
- F-Number measurements for an area are taken in accordance with ASTM E1155 requirements along surveyed transverse and longitudinal lines of the substrate surface and deviations of floor flatness (FF) and floor levelness (FL) are calculated and analyzed. Compliance is considered satisfactory if the composite values of the entire installation are greater than or equal to the overall F-number value of the specified method's designated Class value (e.g. "Overall F-Number" of CSA A23.1 Table 19 - Slab and Floor Finish Classifications) with no placement less than two-thirds of the specified Class value (except minimum FF/FL values shall not be less than FF15/FL10).
Both the ACI and CSA F-Number Systems apply to 99% of all floor slabs that support "random" pedestrian or vehicular traffic. In the small percentage of floors that have "defined" traffic where vehicle traffic lateral (side-to-side) and vertical (up and down) movement must be restricted (e.g., as with high-lift forklifts accessing high vertical storage racks), a different F-Number, Fmin (indicated as FMIN), is used. Most super flat floors use the FMIN System, since most support defined traffic.
Note to concrete finishers
The quickest, easiest, and least expensive way to improve floor flatness (FF) is to replace the bull float with a highway straightedge. This alone may result in a 25 to 50% increase in F-Number values. To achieve FF numbers above 40, the distance between edge forms may have to be reduced below 25 feet. In regard to floor levelness (FL), the accuracy in setting forms and the accuracy of strike-off operations have the greatest impact. In both cases more labour is generally required to achieve higher F-Numbers because of the increased number and intensity of operations.
The quickest, easiest, and least expensive way to improve floor flatness (FF) is to replace the bull float with a highway straightedge. This alone may result in a 25 to 50% increase in F-Number values. To achieve FF numbers above 40, the distance between edge forms may have to be reduced below 25 feet. In regard to floor levelness (FL), the accuracy in setting forms and the accuracy of strike-off operations have the greatest impact. In both cases more labour is generally required to achieve higher F-Numbers because of the increased number and intensity of operations.
Note: Only one of the three methods noted above should be specified by the design authority. The ASTM waviness and F-number methods to determine Flatness and level
tolerances are more precise but costlier. For additional information refer to ACI publications 117 and 302.1R as well as NFCA Appendix AA2 - Floor Flatness and Levelness.
tolerances are more precise but costlier. For additional information refer to ACI publications 117 and 302.1R as well as NFCA Appendix AA2 - Floor Flatness and Levelness.
- After review of these flat/level tolerances and due to the realization that such flatness and levels were not being attained by concrete installers and finishers the CSA committee on concrete finishes revised them in accordance with the following:
- Current (2016) slab and floor finish classifications and flat/level tolerances defined in accordance with CSA A23.1 09 (R2014), Table 22 are as follows:
After review of these "new" CSA slab and floor finish classifications and level tolerances with those still required by NFCA for floor finishes NFCA has decided on the following criteria:
- Notwithstanding the slab and floor finish classifications and flat/level tolerances noted in current CSA A23.1, ASTM E1155, or ASTM E1486 consensus standards noted above, the slab and floor finish classifications and flatness tolerances required by NFCA at the time of floor covering installation shall be as follows:
All substrate surfaces scheduled for floor covering installation shall be provided by the Contractor in accordance with ASTM F710
Straightedge values for all substrates, on grade or elevated, old or new shall not exceed: A. Broadloom Carpet 1/4" over 10' (6mm over 3m) B. Resilient (Vinyl, Rubber, Linoleum) Carpet Tile, Hardwood, Laminate, Bamboo 3/16" over 10' (4.5mm over 3m) Or be in accordance with individual manufacturers installation guides for each product. Refer to A21 Best Practices for Measuring Substrate Flatness for Floor Covering Installations Note: FF/FL measurement method according to ASTM E1155 shall be limited to determining concrete tolerances have been met. FF/FL measurement method cannot be used to determine Flatness acceptability for the floor covering installation work. |
Note: The below graphic illustrates how Floor Flatness (FF) numbers, and straight edge measurements, can drop off over time as new concrete deflects after pour.
Note: Flatness tolerances are initially more stringent for suspended concrete slabs due to slab sag after formwork is removed. This measure however does not alleviate the requirements of the General Contractor to provide final flatness tolerances required for suspended slabs. The use of a Hydraulic Cement (self levelling) Underlayment will be required where any of the above noted tolerances can not be achieved (see below).
- In addition, where a variety of floor finishes (i.e., resilient carpet, hardwood, laminate and ceramic flooring) are to be installed over a concrete surface (such as a floor plate in high-rise construction), such surfaces (i.e. the whole floor plate in this case) shall be finished at time of placement to suit the most critical flatness and levelness requirements unless such areas are locally separated by concrete walls. As this may not be easily or realistically attainable due to quality of finishing work, slab deflection, etc. then the following or other means must be considered by the Owner, Design Authority / Specifier to provide such levels.
.09 Deflection
Deflection: Non‑permanent change to localized surface level (tilt or slope) caused by bending of suspended floors between supports when loads are applied and removed, similar to the surface of a trampoline when someone is standing in the middle of the mat.
Self‑levelling underlayments and concrete toppings can be used to correct changes to floor levelness arising from camber and deflection when building owners have identified floor levelness as a stated outcome. The structural engineer will account for additional material loads when level floors are required, and will specify products for correction of camber and deflection as a standalone specification requirement.
- Deflection is described as a ratio of the length of span divided by a stiffness factor ranging from L/180 to L/900 with the higher number representing higher stiffness.
- Not‑So‑Stiff Floor Plate: L/240 for a 9 metre (30’) span has a stiffness factor of 240 and will deflect 38 mm (1½”) under maximum loading.
- Reasonably Stiff Floor Plate: L/360 for a 9 metre (30’) span has a stiffness factor of 360 and will deflect 2 mm (1”) under maximum loading.
- Very Stiff Floor Plate: L/720 for a 9 metre (30’) span has a stiffness factor of 720 and will deflect 12.5 mm (½”) under maximum loading.
- The amount of deflection is determined by the structural engineer, and is coordinated with the architect and interior designer based on the type of occupancy.
- Floor covering manufacturers may indicate limitations to floor stiffness when their products are affected by this type of movement, such as with rigid materials that may require higher stiffness values than resilient materials to prevent cracking or debonding.
- Deflection cannot be corrected using standard surface preparation materials and does not form a part of the work performed by floor covering trades.
Self‑levelling underlayments and concrete toppings can be used to correct changes to floor levelness arising from camber and deflection when building owners have identified floor levelness as a stated outcome. The structural engineer will account for additional material loads when level floors are required, and will specify products for correction of camber and deflection as a standalone specification requirement.
.10 Camber
Permanent change to localized surface level (tilt or slope) caused by bending of suspended floors between supports from the weight of the floor plate itself when formwork and temporary shoring is removed.
- The amount of camber can be estimated by the structural engineer and incorporated into formwork or structural elements as a reverse camber, but cannot be controlled as an absolute level floor plate.
- Camber can be affected by the timing for removal of formwork and shoring or application of temporary construction loads (equipment, material storage) before the floor plate has reached its design strength.
- Camber can also be affected by weather conditions at time of placement, time that concrete spent in transit, the natural properties of concrete and other factors.
- Camber correction is not always accounted for in the structural design since this condition does not affect the occupant safety when using the floor plate, or may not form a part of the project budget.
- Camber cannot be corrected using standard surface preparation materials and does not form a part of the work performed by floor covering trades.
.11 Adjusting Concrete Levels:
- Minor discrepancies in new or existing surfaces levels can be adjusted by using patching and filling compounds. This is considered, within reason, part of the flooring contractor's work.
- Where flatness/level discrepancies are too large, i.e. where the thickness of patching and filling compounds required exceeds NFCA tolerances noted herein, floor flatness/levels must be corrected by using a Hydraulic Cement (self-levelling) Underlayment capable of bonding to prepared substrate surfaces and being installed from 3mm (1/8") to 13 mm (1/2") thick in one pour and up to 25 mm (1") thick in small areas. The material must be capable of being feather edged or tapered without fracturing in order to not leave ridges and to match existing elevations. Such material should achieve a compressive strength of 3500 psi after 28 days by air cure only, be capable of being walked on after 3 hours without damage, and be capable of being coated after 24 hours at 21°C (70°F). Substrate preparation is critical for bonding of this material.
- The application of cementitious underlayments shall be done by others (the General Contractor or Owner) in a timely manner before the installation of flooring materials or may be undertaken by the floor covering contractor as an additional cost to flooring work.
Examples of sub-floor correction that falls outside of the flooring contractors Trade Scope of Work.
.12 Concrete Curing:
- Sufficient curing time should always be allowed for concrete substrates to develop adequate strength prior to subjecting them to loading or finish work. Curing should be started as soon as the curing method or medium (of types pre-approved by the applicable flooring material manufacturers) can be applied without damaging the surface.
- During initial curing, concrete surfaces should be kept uniformly wet or moist. Partial drying of any part of the surface should not be allowed as it may result in crazing or cracking of the surface.
- Curing methods using water (such as sprinkling and the use of wet coverings) are the most effective and should be used whenever practical. Although not usually as effective as curing with water and wet coverings, moisture retention membranes (curing compounds) are widely used because of their convenience.
- Curing compounds should not be used for slabs intended for further surface treatment, or for slabs intended for adhered flooring materials unless they are known to be compatible with adhesive, since bonding properties of adhesive or other materials may be affected.
- Concrete substrates, even with adequate curing time, can present an unacceptable moisture condition by allowing excessive amounts of moisture vapour to pass through to the surface. This can be a problem even on suspended concrete floors.
- Concrete substrates containing lightweight aggregate or concrete substrates cast in steel or plastic pans retain moisture for long periods of time and may need a much longer drying time. Such substrates should not be covered with resilient floor covering unless proven to be dry.
- It is not enough to assume that a concrete substrate has cured after a designated time period. There are, in fact, a number of variables that affect concrete curing:
- The amount of water in mix versus cement and aggregate content.
- Inclusion of fly ash and admixtures that will affect the curing time. Note that the use of fly ash will noticeably extend concrete curing times.
- Time of year when placed as the relative humidity (above 80%) and temperature (below 20°C) will affect curing time.
- Use of sealers after installation that will retard the release of moisture.
- The actual slab thickness - the thicker the concrete the longer it will take to "dry" all factors remaining the same.
- The type of slab (i.e. slab-on-grade versus a suspended slab). Suspended slab can dry on both sides speeding up the process.
- If a vapour retarder/ waterproof membrane is used under the slab.
- The type of formwork material used for suspend slabs – slabs formed using metal or plastic pan systems may take longer to cure than those formed using wood framing.
- The amount of heat within the area from the sun or from heating sources to aid in the drying process
- The amount of natural or forced ventilation available to exhaust moisture.
- The amount of surface porosity of the finished slab – a steel towelled and polished (densified) surface will take longer to dry.
- There are also a number of methods that may be used to speed up the drying process. Subject to the pre-approval of the Structural Consultant, these are:
- Increasing the temperature within the area and providing additional ventilation to permit the escape of moisture-laden air.
- Placing dehumidifiers in strategic locations to extract moisture from the area and from the slab.
- Subject to the finish requirements for the type of flooring to be installed, the use of curing and sealing compounds should be restricted as they slow concrete hydration resulting in slow curing slabs thus retaining moisture within the concrete long after the curing period. The use of such compounds may also be incompatible with the type of flooring adhesives to be used.
- Subject to the finish requirements for the type of flooring to be installed, the use of curing and sealing and hardening compounds or the presence of a very dense / polished surface finish may retain moisture within the concrete long after the curing period. These treatment and finishes could be removed by grinding, sanding, or shot blasting to allow for the faster emission of static and dynamic moisture from the slab.
- New concrete substrates must be properly cured and thoroughly dry before commencement of any flooring installation. As curing depends on such things as the environmental conditions, the location of the slab and the time of year, substrate surfaces may require more drying time than normal before they may be considered ready for moisture testing.
5 • TESTING OF SUBSTRATES
.01 All substrates, notably concrete surfaces, shall be tested for moisture, alkalinity, porosity, Concrete Surface Profile (CSP), soundness and rigidity, strength, temperature, and flatness prior to the application of any flooring material in accordance with NFCA requirements. Refer to NFCA Reference Manual Part A11 - Substrate Testing.
.02 All wooden substrates shall be of a suitable type approved for installation beneath the specified floor covering type. They shall be stamped as an approved underlayment type, tested for moisture, correct fastening and acceptable flatness prior to the application of any flooring material in accordance with NFCA requirements. Refer to NFCA Reference Manual Part A11 - Substrate Testing.
.03 The Owner or General Contractor must submit a written report on moisture and surface alkalinity of concrete substrates to determine its suitability for the material to be installed to the flooring contractor.
.01 All substrates, notably concrete surfaces, shall be tested for moisture, alkalinity, porosity, Concrete Surface Profile (CSP), soundness and rigidity, strength, temperature, and flatness prior to the application of any flooring material in accordance with NFCA requirements. Refer to NFCA Reference Manual Part A11 - Substrate Testing.
.02 All wooden substrates shall be of a suitable type approved for installation beneath the specified floor covering type. They shall be stamped as an approved underlayment type, tested for moisture, correct fastening and acceptable flatness prior to the application of any flooring material in accordance with NFCA requirements. Refer to NFCA Reference Manual Part A11 - Substrate Testing.
.03 The Owner or General Contractor must submit a written report on moisture and surface alkalinity of concrete substrates to determine its suitability for the material to be installed to the flooring contractor.
6 • CONCRETE SUBSTRATES
.01 Refer to General and Concrete Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 In general, all concrete substrate surfaces shall be in accordance with NFCA minimum requirements, the floor covering material manufacturer's recommendations, and the following conditions
.03 The following requirements for both new and existing concrete substrate (or subfloor) classifications apply:
.05 All new concrete substrates must be structurally sound, adequately cured, clean, dry, free from dust, solvents, paint, plaster, oil, grease, curing / breaking / parting / retarding compounds, sealing and admixture compounds prior to the installation of any floor covering material.
.06 Existing concrete substrates must similarly be smooth, level, structurally sound, and free from moisture, alkali, dust, solvents, paint, wax, oil, grease, asphalt, sealing compounds and any other extraneous foreign materials.
.07 Dusting concrete surfaces are not acceptable. Such subfloors must be restored to meet the floor covering manufacturer's requirements for the products specified.
.01 Refer to General and Concrete Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 In general, all concrete substrate surfaces shall be in accordance with NFCA minimum requirements, the floor covering material manufacturer's recommendations, and the following conditions
.03 The following requirements for both new and existing concrete substrate (or subfloor) classifications apply:
- Below Grade Concrete Substrates: Many flooring material manufacturers may not permit their products and adhesives to be installed on below grade concrete substrates. Some flooring materials may however be installed that may otherwise be restricted provided such substrates are installed over a vapour retarder / moisture barrier to requirements noted herein and the concrete moisture content is proven to be within the manufacturers requirements.
- On Grade Concrete Substrates: Subject to their pre-approval, many flooring manufacturers may permit their products and adhesives to be installed on grade concrete substrates that may otherwise be restricted provided such substrates are installed over a vapour retarder / moisture barrier to requirements noted herein and the concrete moisture content is proven to be within the manufacturers requirements.
- Suspended Concrete Substrates: Provided that the general and concrete requirements noted above are met, all types of floor covering may be installed.
- All such substrates shall be tested by an independent agency for moisture and alkalinity content in strict accordance with NFCA requirements. Test results must show acceptable conditions before commencement of any floor covering installation.
.05 All new concrete substrates must be structurally sound, adequately cured, clean, dry, free from dust, solvents, paint, plaster, oil, grease, curing / breaking / parting / retarding compounds, sealing and admixture compounds prior to the installation of any floor covering material.
.06 Existing concrete substrates must similarly be smooth, level, structurally sound, and free from moisture, alkali, dust, solvents, paint, wax, oil, grease, asphalt, sealing compounds and any other extraneous foreign materials.
.07 Dusting concrete surfaces are not acceptable. Such subfloors must be restored to meet the floor covering manufacturer's requirements for the products specified.
.08 Whenever a powdery or porous surface is encountered, a primer compatible with the adhesive shall be used to provide a suitable surface for the glue-down installation.
.09 Patching of minor cracks and depressions shall be made by using an appropriate and compatible latex or polymer fortified cementitious patching compound. Do not exceed manufacturer's recommendations for patch thickness. Large patched areas must be primed.
.10 Patching, if required, shall be in strict accordance with Part A09 requirements, and as noted in item 3.07 herein.
.09 Patching of minor cracks and depressions shall be made by using an appropriate and compatible latex or polymer fortified cementitious patching compound. Do not exceed manufacturer's recommendations for patch thickness. Large patched areas must be primed.
.10 Patching, if required, shall be in strict accordance with Part A09 requirements, and as noted in item 3.07 herein.
.11 Concrete Surface Laitance
Removal is vital to allow a successful subfloor installation and avoid any costly and timely corrective work in the future.
- Laitance is a major cause of failure in flooring installations. Appearance is that of a milky looking surface deposit, is a weak, friable layer on the surface of concrete and sand cement screeds which appears after curing.
- It is made from hydrated cement and fine aggregates (particles) that rise to the surface when too much water is added. It may also be due to rain damage during placing, or from over trowelling. Subsequent poor curing of the surface will also contribute towards the formation of laitance.
- Laitance is always present on new concrete and must be removed. However, sur face laitance is not to be confused with a poor quality concrete or screed that needs addressing in another way.
- Laitance comes in varying degrees of thickness, from a fine dust to several millimeters or more, depending on contributing factors.
- To determine the thickness of the laitance, flooring contractors should score the sur face of the substrate with a steel edge until reaching the main aggregate.
- Proprietary scratch testing equipment is available which can be used as a guide to determining the depth of laitance.
- If laitance is left untreated, the application of subsequent materials, such as smoothing underlayments, will have a high risk of failing.
- Although it may not be immediately evident, trafficking impact and the stress imposed on the bond line through repeated fluctuations in temperature will eventually cause the laitance inter face layer to delaminate, resulting in the flooring installation failing and costly remedial work.
- Shot blasting is the fastest and most efficient form of laitance removal, especially in large areas. Shot blasting machines are available in varying sizes making them ideal for use on most surfaces, no matter the size. Using a shot blaster will allow up to 1000sq m of flooring to be prepared in just one day and, as shot blasting is a dry process, floorcovering installation may continue in other areas of the room while the surface preparation process is taking place.
- Mechanical planing is a method often used to remove greater thicknesses of laitance. Also referred to as concrete planing, the machines used carry rows of rotating cutters tipped with tungsten to provide an excellent removal of laitance.
- Scrabbling, grinding and abrading are also recommended for removing laitance. Handheld grinding machines, designed for precision, control and safe operation are recommended for use in smaller areas and edge detail.
Removal is vital to allow a successful subfloor installation and avoid any costly and timely corrective work in the future.
7. WOODEN SUBSTRATES
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 New and existing wood framing systems supporting wood substrates: The following general requirements for both shall apply.
.02 New and existing wood framing systems supporting wood substrates: The following general requirements for both shall apply.
- All wood framing systems shall be designed to span between supports in accordance with Building Code load and deflection requirements to provide a structurally sound system free of vertical movement and horizontal expansion that would be detrimental to flooring materials installed as well as to provide acoustical and fire separation in accordance with Building Code requirements.
- All wood flooring systems over crawl spaces shall be designed in accordance with the above noted requirements with the clearance to the underside of the wood framing system to be a minimum of 300 mm (12") above the interior grade surface (except 450 mm (18") where required by Code). This "crawl" space (unless insulated and used as a warm air plenum) shall be either naturally cross or mechanically ventilated and must have an approved moisture impervious barrier in accordance with Building Code requirements to prevent rising ground vapour moisture from causing damage detrimental to the flooring assembly from dry rot, mould, mildew, swelling, and buckling, etc. (The relative humidity within the space shall not exceed more than 70%).
- The moisture impervious barrier may be 50 mm (2") of asphalt or concrete, Type S roofing or 0.15 mm (6 mil) polyethylene sheet. Alternately, if the joist spaces are insulated and where approved by authorities having jurisdiction, the framing system may be sealed on the underside using a moisture retarder installed on the warm side (i.e., fixed to underside of floor sheathing with floor joists wrapped prior to installing insulation).
- Moisture: All wood substrates (i.e. floor sheathing) that were installed wet or that have been exposed to the elements before closing in the area must be tested for moisture content and confirmed dry in accordance with the floor covering, adhesive and/or panel underlayment manufacturers requirements before application. An electronic pin moisture meter set to the correct wood species type and reading no more than 12% moisture content is a general guide. In all cases ensure the substrate meets the manufacturers requirements for subfloor moisture content before proceeding with installation.
- Flatness: All wood substrates, subfloors and underlayments shall be provided smooth, flat (not undulating) to within 3/16" over 10' with no abrupt changes and/or in accordance with the floor covering material manufacturer's recommendations and in accordance with requirements noted below.
.03 Subfloor Sheathing: Plywood, hardwood, particle board, or oriented strand board used as subfloor sheathing must conform to and be installed in strict accordance with building code requirments in regard to acceptable materials, thickness, support, span, and fastening. Where flooring materials (such as carpet) are installed directly over these materials (i.e., an underlayment is not used) particular attention must be paid in regard to panel edge fastening and gaps. Such subfloor materials and their installation must also be acceptable for use by the flooring material manufacturer and be installed in strict accordance with the floor covering material manufacturer's requirements as well.
.04 Panel Underlayments: Plywood, hardwood, particle board or any other panel products used as a floor underlayment must be of a type that is specifically manufactured by the materials manufacturer for that purpose and must also be of a type that is pre-approved for this use by flooring material manufacturer. Such material must be installed in strict accordance with Building Code and the floor covering material manufacturer's requirements.
Note: Where the project installation is to meet LEED requirements any construction adhesive used in fastening underlayments shall meet LEED VOC requirements.
Special Note: Floor Covering Manufacturers do not recommend the installation of resilient flooring over wood panels attached directly to on grade or below grade concrete
subfloors, or over sleeper constructed subfloors on or below grade concrete slabs. Refer to the specific floor covering manufacturer's recommendations for the above noted
subfloors, or contact local floor covering dealer for detailed information.
.05 Underlayment Warranties: Except for specific flooring underlayment panel products recommended by the flooring manufacturer, the responsibility for underlayment warranties and/or performance guarantees rests with the underlayment panel manufacturer.
Note: Where the project installation is to meet LEED requirements any construction adhesive used in fastening underlayments shall meet LEED VOC requirements.
Special Note: Floor Covering Manufacturers do not recommend the installation of resilient flooring over wood panels attached directly to on grade or below grade concrete
subfloors, or over sleeper constructed subfloors on or below grade concrete slabs. Refer to the specific floor covering manufacturer's recommendations for the above noted
subfloors, or contact local floor covering dealer for detailed information.
.05 Underlayment Warranties: Except for specific flooring underlayment panel products recommended by the flooring manufacturer, the responsibility for underlayment warranties and/or performance guarantees rests with the underlayment panel manufacturer.
.06 Panel Underlayment Requirements:
Note: Where the installation is to meet LEED requirements any (construction) adhesives used in fastening underlayments shall meet LEED VOC requirements.
Note: Where the installation is to meet LEED requirements any (construction) adhesives used in fastening underlayments shall meet LEED VOC requirements.
- Underlayment panels shall be designated "Underlayment Grade" panels that are warranted by the panel manufacturer for use under the specified flooring for the following conditions.
- Commercial / Institutional or other heavy use / load areas.
- Commercial and/or Residential areas.
- Residential areas only.
- The minimum underlayment panel thickness shall be 10 mm (3/8"), unless thicker panels are required to suit design requirements.
- Underlayment panels shall be free of internal voids, knot holes, splits or cracks and be complete with an upper surface that is sufficiently dense and smooth so that surface grain or texture will not be telegraphed to the surface of any new resilient flooring to be installed. Panels shall also be resistant to common static or dynamic load exposure and shall not contain bond laminates that will cause staining of installed resilient and in some instances, carpet flooring (e.g., void fillers, identification stamp, etc.).
- Plywood underlayment panels shall be installed with the face grain perpendicular to the supports. All joints should be snug but free of edge pressure.
- Underlayment panels shall be installed in strict accordance with the panel manufacturer's written requirements in regard to type and spacing of fasteners and/or adhesive and in accordance with applicable Building Code requirements, except panel thickness and fastening shall be to NFCA requirements noted herein.
- For recommended types of underlayment grade wood panels contact the:
- Council of Forest Industries of B.C.
- Canadian Plywood Association.
- Structural Board Association.
- Floor Covering Manufacturer / Distributor of products specified.
- Sheathing grade plywood as an underlayment is not recommended. The use of such underlayment panels have in fact been the contributing factors in a number of flooring failures. Generally, the course surface irregularities are telegraphed to the surface of the newly installed flooring resulting in an unacceptable appearance.
- Particle Board and Hardboard Underlayments: Most floor covering manufacturers do not approve of the use of a particle board, flakeboard, chip board or hardboard type underlayment, with the exception of those types rated as "Flooring Underlayment Grade", for use under any resilient flooring products which are specified for a full-spread adhesive installation system. Only products suitable for modified loose-lay or total loose-lay resilient flooring sheet installations may be recommended over these underlayments.
- Joints Around Plywood / Underlayment Panels:
- The adjoining edges of plywood and underlayment panels shall be butted to a light contact, and adjoining panels shall be flush, level and free of vertical movement.
- Minor imperfections shall be sanded smooth if recommended by the panel manufacturer and filled with a non-shrinking latex-modified Portland cement based patching compound.
- To avoid panel joint telegraphing, only gaps between panels in excess of 1.5 mm (1/16") require filling for most lines of flooring.
.07 Fastening of Wood Flooring Substrates and Underlayments:
- The type, size, gauge, length and finish of fasteners (nails, staples, or screws) used for fastening to wood surfaces, existing old flooring or directly to joists shall conform to Part 9 requirements of the applicable National Building Code, Provincial Building Code or City Building By-Law and panel manufacturer's recommendations, unless otherwise noted herein.
- Unless otherwise required by the underlayment panel manufacturer, panel nail and screw fasteners for fixing underlayment to subfloor surfaces shall be placed 10 to 16 mm (3/8" to 5/8") from panel edges and spaced not more than 150 mm (6") o.c. along panel edges and 200 mm (8") o.c. both ways over remainder of panel face.
- The following types of fasteners and methods are permitted as noted:Note: Adhesive should not be permitted to seep up between panel edges or come in contact with the flooring as it can stain some vinyl floors.
Note: Where the installation is to meet LEED requirements any adhesives used shall meet LEED VOC requirements.- Nail Fasteners: Nail fasteners shall be annular grooved flooring nails or spiral nails driven perpendicular and countersunk slightly below underlayment panel surfaces. Straight shank nails are not permitted.
- Staple Fasteners: The use of staple fasteners for fixing underlayment panels is permissible if they are acceptable to the authority having jurisdiction. If acceptable, staples shall be spaced every 50 mm (2") along panel edges and at 75 mm (3") o.c. both ways over remainder of panel face.
- Screw Fasteners: The use of screw fasteners for fixing is permissible if they are acceptable to the authority having jurisdiction. The floor covering industry prefers this system of subfloor installation over nailing. If acceptable it is important to select the correct type of screws. Only recommended flooring screws must be used. Drywall or similar fastening screws are not acceptable. Screw heads must be flush with underlayment panel surfaces.
- Adhesive Fastening: The use of adhesive (in conjunction with nailing or screwing) for fixing underlayment panels is permissible providing this method of installation is acceptable to the authority having jurisdiction. The type of glue used shall not impair the final floor covering installation and/or the particular flooring materials specified. Non-solvent based adhesives should only be considered.
- Nail Fasteners: Nail fasteners shall be annular grooved flooring nails or spiral nails driven perpendicular and countersunk slightly below underlayment panel surfaces. Straight shank nails are not permitted.
- Unless otherwise required by the underlayment panel manufacturer, panel nail and screw fasteners for fixing underlayment to subfloor surfaces shall be placed 10 mm (3/8") to 16 mm (5/8") from panel edges and spaced not more than 150 mm (6") o.c. along panel edges and 200 mm (8") o.c. both ways over remainder of panel face.
- If the nail / screw / gluing method is acceptable, the pressure applied by the fasteners on the glue line should be at least 0.7 to 1.0 Mpa. Nail or screw spacing recommended for the gluing technique is generally closer in order to develop uniform pressure along the glue line. Nail sizes and spacing for various thickness of panels and other information in regards to this system of panel installation are available from the manufacturer or their respective agencies (e.g. Panel Board Association, COFI).
.08 Felt Underlays: The installation of lining felt over wood panel flooring prior to installing floor covering products is not generally recommended except for hardwood flooring. Manufacturers should be consulted prior to its use.
.09 Painted Wood Substrates: The suitability of painted wood surfaces can be checked by gluing down strips of the flooring materials to be installed using the selected adhesive. If,
after approximately 72 hours, the bond is strong and the paint does not pull up with the floor covering material, it is generally considered safe to proceed with the installation.
Installing some flooring materials over a painted wood substrate may void all applicable warranties. Glossy surfaces should always be lightly sanded and vacuumed prior to
installation.
.10 Pressure Treated or Fire Retardant Treated Wood Surfaces: Where such materials are used as a substrate they may not be suitable for the application of floor covering materials. Such material is chemically treated under pressure to alter its physical properties in regard to outdoor exposure or flame retardancy. While some installations may
appear to be initially successful, the floor covering material or its adhesive could be subject to chemical degradation when applied over such treated surfaces. Installations
performed over pressure-treated wood substrates may void all applicable warranties - this should be verified with both the floor covering material and adhesive manufacturers.
.09 Painted Wood Substrates: The suitability of painted wood surfaces can be checked by gluing down strips of the flooring materials to be installed using the selected adhesive. If,
after approximately 72 hours, the bond is strong and the paint does not pull up with the floor covering material, it is generally considered safe to proceed with the installation.
Installing some flooring materials over a painted wood substrate may void all applicable warranties. Glossy surfaces should always be lightly sanded and vacuumed prior to
installation.
.10 Pressure Treated or Fire Retardant Treated Wood Surfaces: Where such materials are used as a substrate they may not be suitable for the application of floor covering materials. Such material is chemically treated under pressure to alter its physical properties in regard to outdoor exposure or flame retardancy. While some installations may
appear to be initially successful, the floor covering material or its adhesive could be subject to chemical degradation when applied over such treated surfaces. Installations
performed over pressure-treated wood substrates may void all applicable warranties - this should be verified with both the floor covering material and adhesive manufacturers.
.11 Existing Hardwood Flooring Surfaces: Where used as a substrate for new flooring installations, whether over a single layer or double layer subfloor, the installation of new
flooring shall be contingent on the following minimum requirements:
flooring shall be contingent on the following minimum requirements:
- The flooring support system shall meet minimum Code requirements and general requirements noted herein.
- The flooring shall be dry, structurally sound, smooth, level, and free from contaminates.
- Where the hardwood strips are 75 mm (3") or less in face width or are not tongue and grooved, the hardwood shall be covered with 10 mm (3/8") or thicker underlayment panels. Where such hardwood is severely cupped or worn it shall be covered with 13 mm (1/2") or thicker underlayment panels.
- Where the hardwood strips are greater than 75 mm (3") in face width or are not tongue or grooved, the hardwood shall be covered with 13 mm (1/2") or thicker underlayment panels.
- For economic reasons and if pre-approved by the flooring manufacturer existing hardwood flooring shall be level-sanded and an approved separation layer (lining felt) shall be adhered over the flooring before the installation of any new flooring.
- New hardwood flooring may be installed over existing hardwood flooring if the existing flooring is smooth, sound, level and the new flooring is installed at right angles to the existing flooring.
- Where glue down carpet installation is to be installed, the flooring surface shall be lightly diagonally sanded and vacuumed to remove contaminates and finishes to achieve a surface acceptable for the application adhesive materials
.12 Existing Double Layer Wood Substrates: When used as a substrate, existing double wood floor substrates (i.e., subfloor sheathing or boards and underlayment or hardwood
flooring) must be free of all movement and must have:
flooring) must be free of all movement and must have:
- All defective or badly worn boards replaced and all loose boards or panel type subfloor sheathing securely re-fastened.
- Minimum 10 mm (3/8") thick underlayment panels installed in ashlar pattern at right angles over floor boards or subfloor sheathing panels.
- Single layer wood substrates (subfloors) consist of one layer of plywood acting both as subfloor sheathing and as an underlayment. Such plywood shall be minimum 19 mm (3/4") thick T&G Douglas Fir or Canadian Softwood Plywood having the same top surface requirements as panel underlayments.
- Single layer plywood substrates shall be installed with the surface ply grain at right angles to the floor joist direction with plywood panel ends on solid bearing and panel edges between joists fully supported on not less than nominal 38 x 89 mm (2" x 4") solid blocking. The spacing of floor joists for such panel substrates shall not exceed 400 mm (16") o.c.
- Single layer wood substrates shall only be used where permitted by Code / authorities having jurisdiction. The use of this substrate as an acceptable surface for resilient flooring, carpet or hardwood flooring shall be in strict accordance with Code and NFCA minimum requirements.
.14 New Double Layer Wood Substrates:
Note: Subfloor sheathing panel or board thicknesses indicated in the applicable Building Code are minimum requirements and may not be sufficient or adequate for all flooring materials to be installed. The Consultant / Specifying authority shall select appropriate materials and provide thickness with regard to allowable maximum deflection and minimum support requirements for flooring in mind.
Note: Subfloor sheathing panel or board thicknesses indicated in the applicable Building Code are minimum requirements and may not be sufficient or adequate for all flooring materials to be installed. The Consultant / Specifying authority shall select appropriate materials and provide thickness with regard to allowable maximum deflection and minimum support requirements for flooring in mind.
- Double layer wood floor substrates consist of a subfloor sheathing material with a panel type underlayment above. The subfloor sheathing material may be subfloor panels approved by Code or nominal 25 mm (1") thick boards not over 200 mm (8") wide, laid diagonally to the joists with all ends cut and completely supported.
- The thickness, edge support and edge treatment of subfloor sheathing panels shall conform to applicable Code Part 9 requirements.
- Underlayment panels installed over any subfloor sheathing or board materials shall conform to applicable Code minimum requirements and to NFCA thickness and fastening requirements noted herein.
.15 Additional layer of sheathing over non-compliant subfloors to receive wood flooring:
- A second (top) layer should be aligned and installed perpendicular to the floor framing and offset by a minimum 4" (100mm) and end joints by at least one joist space. No base layer seams should align with the top layer seams.
- The top layer 15/32" should be fastened with ring nails or screw shanked nails or equivalent with penetration not exceeding the depth of the base layer (must not penetrate through to the floor joist).
- A suitable elastomeric wood floor or subfloor adhesive is recommended.
8 • SUBSTRATES WITH EXISTING RESILIENT FLOORING
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 The installation of new flooring over existing resilient flooring may be considered for economical and/or time saving reasons. Specifiers and consumers should be aware however that this type of installation over existing resilient flooring may create flooring problems at a later time. These include:
.04 Where the manufacturer of new flooring approves of the installation of their flooring over existing resilient flooring the existing flooring must be tightly bonded to the substrate surfaces and its surface must be free of oil, grease, wax, and dirt and all contaminants must be stripped from the surface. In addition any embossing, dents, and indentations must be filled with approved filler.
Note: A maximum of two ( 2) layers of resilient flooring may be acceptable in this regard.
.05 Vinyl Asbestos Tile (VAT) and/or Vinyl Composition Tile (VCT): The application of new flooring materials over VAT or VCT material is acceptable as long as it is tightly adhered to the substrate and all waxes, sealers, floor finishes, and other foreign materials have been removed. Refer to Asbestos Containing Flooring Materials below.
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 The installation of new flooring over existing resilient flooring may be considered for economical and/or time saving reasons. Specifiers and consumers should be aware however that this type of installation over existing resilient flooring may create flooring problems at a later time. These include:
- Telegraphing of surface imperfections of the existing flooring.
- Surface indentations from static or rolling loads due the type of existing resilient flooring thus jeopardizing the appearance of the new flooring.
- Adhesive bond failure between one or both layers of flooring due to foot and wheeled traffic and static loads resulting in buckling or bubbling of new flooring.
- Loosening, delamination, and bonding failure of existing resilient flooring resulting in movement of the new flooring.
- The installation of flooring over existing resilient flooring must be verified and approved by the material manufacturers before installation. Contact the floor covering manufacturer and/or the flooring contractor for information on the suitability of existing flooring, selection of new flooring, and the potential problems that may be encountered. Unless specifically approved by the floor covering manufacturer, the responsibilities and/or liabilities for the flooring and installation, will lie with the Consumer and/or Floor Covering Contractor in all cases of flooring and/or installation failures.
- Over existing heavily embossed or cushion resilient floors.
- Over existing sheet vinyl, homogeneous, or laminated solid vinyl tile, and some rubber flooring products as these materials may contain vinyl plasticizers, which could migrate into the floor covering adhesive or backing and loosen the bond. Consult the floor covering manufacturers for specific recommendations.
- For tile over tile installations on below grade substrates.
- Where moisture or alkali is present or suspected.
.04 Where the manufacturer of new flooring approves of the installation of their flooring over existing resilient flooring the existing flooring must be tightly bonded to the substrate surfaces and its surface must be free of oil, grease, wax, and dirt and all contaminants must be stripped from the surface. In addition any embossing, dents, and indentations must be filled with approved filler.
Note: A maximum of two ( 2) layers of resilient flooring may be acceptable in this regard.
.05 Vinyl Asbestos Tile (VAT) and/or Vinyl Composition Tile (VCT): The application of new flooring materials over VAT or VCT material is acceptable as long as it is tightly adhered to the substrate and all waxes, sealers, floor finishes, and other foreign materials have been removed. Refer to Asbestos Containing Flooring Materials below.
9 • SUBSTRATES WITH OTHER EXISTING FLOOR COVERING TYPES
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 The installation of a second layer of finish flooring material, including some carpets, can trap moisture, resulting in widespread failure, even over subfloors that had never previously shown any signs of moisture. Appropriate moisture tests should be performed before installing any new flooring materials over any existing resilient tile flooring.
.03 Existing Terrazzo, Ceramic Tile, Marble, Slate and other Nonporous Surfaces: All grout lines should be filled and levelled. If a flooring material is glued down over these surfaces, strict attention must be given to the open time recommendations of the adhesive manufacturer.
.04 New Carpet over Existing Carpet: In the absence of new carpet manufacturer's specific recommendations to the contrary, carpet should not be installed over existing carpet.
.05 Other Substrate Types Not Defined in this Manual: The following substrate types are not included: Magnesite (a compound of magnesium, carbon and oxygen used as a cement-like construction material), steel decks and other metal subfloors, ceramic tile, terrazzo, and marble; neoprene and hypalon coatings, asphaltic mastics, PVA underlayments, hard or soft -set types of epoxy.
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 The installation of a second layer of finish flooring material, including some carpets, can trap moisture, resulting in widespread failure, even over subfloors that had never previously shown any signs of moisture. Appropriate moisture tests should be performed before installing any new flooring materials over any existing resilient tile flooring.
.03 Existing Terrazzo, Ceramic Tile, Marble, Slate and other Nonporous Surfaces: All grout lines should be filled and levelled. If a flooring material is glued down over these surfaces, strict attention must be given to the open time recommendations of the adhesive manufacturer.
.04 New Carpet over Existing Carpet: In the absence of new carpet manufacturer's specific recommendations to the contrary, carpet should not be installed over existing carpet.
.05 Other Substrate Types Not Defined in this Manual: The following substrate types are not included: Magnesite (a compound of magnesium, carbon and oxygen used as a cement-like construction material), steel decks and other metal subfloors, ceramic tile, terrazzo, and marble; neoprene and hypalon coatings, asphaltic mastics, PVA underlayments, hard or soft -set types of epoxy.
10 • ASBESTOS CONTAINING FLOORING MATERIALS
.01 Some sheet vinyl, resilient tile, and cutback asphaltic adhesives may contain asbestos. Unless absolutely positive beyond any doubt that the floor is a non-asbestos product, assume it contains asbestos, and treat it in a manner prescribed for a floor containing asbestos. Recommended work practices prohibit sanding, dry scraping, bead-blasting, or mechanically pulverizing such suspect (asbestos containing) resilient flooring, backing, or lining felt. Do not use power devices that create asbestos dust in removing cutback asphaltic adhesives.
Warning: Sanding of existing resilient tile and sheet flooring, backing or lining felt, or asphalt base adhesive is prohibited. These products may contain asbestos fibres that are not readily identifiable. Avoid creating dust of any kind. Inhalation of asbestos dust may cause serious bodily harm.
.02 If existing flooring and/or adhesive is suspected of containing asbestos during flooring removal and/or installation of new flooring over it, all removal work and/or preparation work for such flooring that requires sanding, dry scraping, or bead-blasting must cease immediately in that area.
.03 The General Contractor and/or Owner must take appropriate action to either confirm or disclaim the presence of friable asbestos. This may mean testing suspect flooring materials and/or consulting the manufacturer of the flooring for confirmation.
.04 If it is determined that the flooring and/or adhesive contains asbestos or is in any way hazardous to workers, the General Contractor and/or Owner must remove such materials or take such measures in strict accordance with requirements of applicable authorities having jurisdiction or arrange and pay for an Asbestos Removal Contractor to remove all such flooring materials and adhesive from the subfloor and site.
.05 Consult with applicable authorities having jurisdiction including the Workers Compensation Board in regard to specific regulations and requirements covering the removal of asbestos containing materials.
.06 It is essential that precautions be observed when preparing or removing floor coverings that may contain asbestos. If asbestos containing resilient flooring is encountered, the Recommended Work Procedures for Resilient Floor Coverings as outlined by the Resilient Floor Covering Institute (www.rfci.com) and/or the particular manufacturer's recommendations may be used as a guide.
.01 Some sheet vinyl, resilient tile, and cutback asphaltic adhesives may contain asbestos. Unless absolutely positive beyond any doubt that the floor is a non-asbestos product, assume it contains asbestos, and treat it in a manner prescribed for a floor containing asbestos. Recommended work practices prohibit sanding, dry scraping, bead-blasting, or mechanically pulverizing such suspect (asbestos containing) resilient flooring, backing, or lining felt. Do not use power devices that create asbestos dust in removing cutback asphaltic adhesives.
Warning: Sanding of existing resilient tile and sheet flooring, backing or lining felt, or asphalt base adhesive is prohibited. These products may contain asbestos fibres that are not readily identifiable. Avoid creating dust of any kind. Inhalation of asbestos dust may cause serious bodily harm.
.02 If existing flooring and/or adhesive is suspected of containing asbestos during flooring removal and/or installation of new flooring over it, all removal work and/or preparation work for such flooring that requires sanding, dry scraping, or bead-blasting must cease immediately in that area.
.03 The General Contractor and/or Owner must take appropriate action to either confirm or disclaim the presence of friable asbestos. This may mean testing suspect flooring materials and/or consulting the manufacturer of the flooring for confirmation.
.04 If it is determined that the flooring and/or adhesive contains asbestos or is in any way hazardous to workers, the General Contractor and/or Owner must remove such materials or take such measures in strict accordance with requirements of applicable authorities having jurisdiction or arrange and pay for an Asbestos Removal Contractor to remove all such flooring materials and adhesive from the subfloor and site.
.05 Consult with applicable authorities having jurisdiction including the Workers Compensation Board in regard to specific regulations and requirements covering the removal of asbestos containing materials.
.06 It is essential that precautions be observed when preparing or removing floor coverings that may contain asbestos. If asbestos containing resilient flooring is encountered, the Recommended Work Procedures for Resilient Floor Coverings as outlined by the Resilient Floor Covering Institute (www.rfci.com) and/or the particular manufacturer's recommendations may be used as a guide.
11 • LIQUID ADHESIVE REMOVERS
.01 There are a number of liquid adhesive removers available that will effectively remove cutback or emulsion adhesive residue from substrate surfaces.
.02 There is however, evidence that these products, including any residue of them left on the substrate surface to which they are applied, may adversely affect or cause failure of the adhesive or floor covering to be used.
.03 In addition, the use of these adhesive removers may void any new adhesive or floor covering warranties.
.01 There are a number of liquid adhesive removers available that will effectively remove cutback or emulsion adhesive residue from substrate surfaces.
.02 There is however, evidence that these products, including any residue of them left on the substrate surface to which they are applied, may adversely affect or cause failure of the adhesive or floor covering to be used.
.03 In addition, the use of these adhesive removers may void any new adhesive or floor covering warranties.
12 • PAINTED OR COATED SUBSTRATES
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding
.02 The bond of any new flooring material (adhesive) to substrates surfaces that have been painted or coated is only as good as the paint and or coating and its bond to the substrate surface. If you bond to old paint, sealers, polish, or other foreign matter, you are dependent upon the bond of that material to the substrate to hold any new flooring material in place. Since you cannot determine how strong that bond may be, it is best to bond directly to the substrate itself.
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding
.02 The bond of any new flooring material (adhesive) to substrates surfaces that have been painted or coated is only as good as the paint and or coating and its bond to the substrate surface. If you bond to old paint, sealers, polish, or other foreign matter, you are dependent upon the bond of that material to the substrate to hold any new flooring material in place. Since you cannot determine how strong that bond may be, it is best to bond directly to the substrate itself.
13 • METAL SUBSTRATES
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 Metal substrate surfaces shall be level, clean and be free of grease, oil, dirt, rust, or other contaminates detrimental to installation requirements.
.03 The surface finish of metal substrates shall tested as required to ensure that it is suitable for adhesive bond and compatible with flooring materials to be installed over it.
Note: Where the installation is to meet LEED requirements any adhesives used shall meet LEED VOC requirements.
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 Metal substrate surfaces shall be level, clean and be free of grease, oil, dirt, rust, or other contaminates detrimental to installation requirements.
.03 The surface finish of metal substrates shall tested as required to ensure that it is suitable for adhesive bond and compatible with flooring materials to be installed over it.
Note: Where the installation is to meet LEED requirements any adhesives used shall meet LEED VOC requirements.
14 • RADIANT HEATED SUBSTRATES
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 Refer to Selection, Material, and Installation Guides for all flooring types (and notably carpet, hardwood, laminate, and bamboo flooring) for issues concerning installation of flooring over radiant heated substrates.
.03 With a few exceptions, most flooring types and related materials (e.g. adhesives) can be used on radiant heated substrate surfaces. The manufacturers of any materials used must be contacted in regard to preparation and installation recommendations for flooring products selected, and for any exceptions or exclusions to be followed when they are used over radiant heated substrates. Some adhesives and mastics, for instance, are temperature sensitive.
While radiant heating temperatures (except extreme high and low temperatures) will not harm most flooring types, variances in moisture content may cause them to move in numerous ways (particularly hardwood and laminate flooring). When installing any flooring, moisture content is a key factor to successful floor performance. When installing flooring over radiant heated substrates attention to substrate moisture content becomes even more critical. The flooring installer and the heating contractor both need to be aware of any issues and considerations required when radiant floor heating is used.
.04 Where a substrate surface is heated by in-floor radiant heating, the temperature (i.e., heat) must be lowered and maintained at a specific level before and during the installation of any floor covering material to prevent flooring adhesives from setting too fast and in the case of wood flooring (e.g. hardwood, laminate, bamboo) to prevent flooring from warping.
.05 When fixing tackless strips for carpet in stretch-in installations, or nailing wood flooring members, care must be taken not to nail into the heating system piping or conduit.
.06 Providing that the heating system is designed or regulated not to exceed 30°C (85°F) at floor level, no harmful effect on either the flooring material or adhesives used, takes place according to manufacturer's research, tests and actual field experience.
Note: Excessive heat, or heat build up under furnishings may cause surface indenting and/or discolouration of some floor coverings (particularly resilient flooring)
.07 The most frequent cause of flooring and installation failures is due to latent moisture emissions from the sub floor, premature drying of flooring adhesive, or incorrect installation or use of the heating system. It is therefore critical that the floor covering manufacturer / distributor be contacted for recommendations regarding slab conditioning and installation procedures prior to the installation of any floor covering.
.01 Refer to General Requirements above. Verify acceptable substrate requirements and conditions with material manufacturers of floor coverings to be installed before proceeding.
.02 Refer to Selection, Material, and Installation Guides for all flooring types (and notably carpet, hardwood, laminate, and bamboo flooring) for issues concerning installation of flooring over radiant heated substrates.
.03 With a few exceptions, most flooring types and related materials (e.g. adhesives) can be used on radiant heated substrate surfaces. The manufacturers of any materials used must be contacted in regard to preparation and installation recommendations for flooring products selected, and for any exceptions or exclusions to be followed when they are used over radiant heated substrates. Some adhesives and mastics, for instance, are temperature sensitive.
While radiant heating temperatures (except extreme high and low temperatures) will not harm most flooring types, variances in moisture content may cause them to move in numerous ways (particularly hardwood and laminate flooring). When installing any flooring, moisture content is a key factor to successful floor performance. When installing flooring over radiant heated substrates attention to substrate moisture content becomes even more critical. The flooring installer and the heating contractor both need to be aware of any issues and considerations required when radiant floor heating is used.
.04 Where a substrate surface is heated by in-floor radiant heating, the temperature (i.e., heat) must be lowered and maintained at a specific level before and during the installation of any floor covering material to prevent flooring adhesives from setting too fast and in the case of wood flooring (e.g. hardwood, laminate, bamboo) to prevent flooring from warping.
.05 When fixing tackless strips for carpet in stretch-in installations, or nailing wood flooring members, care must be taken not to nail into the heating system piping or conduit.
.06 Providing that the heating system is designed or regulated not to exceed 30°C (85°F) at floor level, no harmful effect on either the flooring material or adhesives used, takes place according to manufacturer's research, tests and actual field experience.
Note: Excessive heat, or heat build up under furnishings may cause surface indenting and/or discolouration of some floor coverings (particularly resilient flooring)
.07 The most frequent cause of flooring and installation failures is due to latent moisture emissions from the sub floor, premature drying of flooring adhesive, or incorrect installation or use of the heating system. It is therefore critical that the floor covering manufacturer / distributor be contacted for recommendations regarding slab conditioning and installation procedures prior to the installation of any floor covering.
15 • PRIMERS ON SUBSTRATES
.01 The use of primers on substrate surfaces is generally not necessary except for sanded, dusty, porous, or acoustical surfaces.
.02 Priming cannot overcome moisture conditions and must not be used for that purpose.
.03 If used, primers must be thin and fast drying, and be compatible with floor covering adhesives to be used. The adhesive shall be applied only after the primer is dry.
.04 Where lightweight or acoustical concrete is used, refer to the manufacturer's recommendations for the proper primer to be used before any floor covering is installed.
.01 The use of primers on substrate surfaces is generally not necessary except for sanded, dusty, porous, or acoustical surfaces.
.02 Priming cannot overcome moisture conditions and must not be used for that purpose.
.03 If used, primers must be thin and fast drying, and be compatible with floor covering adhesives to be used. The adhesive shall be applied only after the primer is dry.
.04 Where lightweight or acoustical concrete is used, refer to the manufacturer's recommendations for the proper primer to be used before any floor covering is installed.
16 • SUBSTRATE PROTECTION
.01 Prior to installation of floor covering materials all substrates surfaces shall be protected from plaster, gypsum board filler, sprayed materials, paint droppings, grease, oil, or any other spills that may occur during construction and/or renovation work, as all such contaminants have an adverse effect on proper bonding of flooring materials, or may cause staining and/or telegraphing issues at the surface of the resilient flooring.
.02 During early renovation construction, if the subfloor/substrate is found to be sound and stable (i.e. using visual observations, sounding bar, hammer strikes, chain drag, chipping tests, shot blasting, and/or other evaluation methods) then it should be protected from static and dynamic loads as well as accidental impact damage during on-going construction. This may require the use of hardboard or plywood of sufficient thickness to protect the subfloor/substrate from potential fracturing, cracking, delamination, and/or shear damage.
"Sound" refers to the subfloor/substrate being of sufficient integrity, hardness, rigidity, and internal cohesive (i.e. not powdery or flaking) strength to withstand future use activities.
"Stable" refers to the subfloor/substrate's ability to perform without any potential adverse reaction causing delamination, fracturing, or cracking while the floor covering is in service.
.01 Prior to installation of floor covering materials all substrates surfaces shall be protected from plaster, gypsum board filler, sprayed materials, paint droppings, grease, oil, or any other spills that may occur during construction and/or renovation work, as all such contaminants have an adverse effect on proper bonding of flooring materials, or may cause staining and/or telegraphing issues at the surface of the resilient flooring.
.02 During early renovation construction, if the subfloor/substrate is found to be sound and stable (i.e. using visual observations, sounding bar, hammer strikes, chain drag, chipping tests, shot blasting, and/or other evaluation methods) then it should be protected from static and dynamic loads as well as accidental impact damage during on-going construction. This may require the use of hardboard or plywood of sufficient thickness to protect the subfloor/substrate from potential fracturing, cracking, delamination, and/or shear damage.
"Sound" refers to the subfloor/substrate being of sufficient integrity, hardness, rigidity, and internal cohesive (i.e. not powdery or flaking) strength to withstand future use activities.
"Stable" refers to the subfloor/substrate's ability to perform without any potential adverse reaction causing delamination, fracturing, or cracking while the floor covering is in service.
17 • INSTALLATION REQUIREMENTS
.01 Work of the flooring contractor shall be limited to that defined under the Scope of Work for each type of flooring. This includes the correction of minor sub-floor irregularities and/or imperfections, including minor levelling and/or filling with a non-shrinking latex-based patching compound, sanding smooth, and vacuuming clean such surfaces. Where additional corrective measures are required such as the addition of cementitious underlayments these shall be done in a timely manner by others (the Contractor or Owner) or may be done by the flooring contractor at additional cost to the work.
.02 It shall also be the responsibility of the flooring contractor to ensure that environmental and substrate conditions are in accordance with minimum NFCA and floor covering manufacturer's recommendations. Unless otherwise noted in this publication or specified by the flooring material manufacturer the following conditions shall be provided:
.03 The flooring contractor shall not be responsible for the condition of the substrate or for any corrective work undertaken or contracted by the Contractor that may at a later time adversely affect the performance or appearance of the floor covering and /or installation.
.04 Floor covering work shall not commence where there is an indication of moisture or hydrostatic pressure or excess alkalinity. Due to the sensitivity of some flooring types to moisture or alkalinity, all concrete floors shall be tested as previously noted.
.05 Floor covering work shall not commence until all unsatisfactory conditions have been corrected. Any unsatisfactory conditions or defects likely to impair finished work shall be reported in writing to the Owner or Contractor. Commencement of work shall not imply acceptance of surfaces and conditions, except as qualified herein.
.01 Work of the flooring contractor shall be limited to that defined under the Scope of Work for each type of flooring. This includes the correction of minor sub-floor irregularities and/or imperfections, including minor levelling and/or filling with a non-shrinking latex-based patching compound, sanding smooth, and vacuuming clean such surfaces. Where additional corrective measures are required such as the addition of cementitious underlayments these shall be done in a timely manner by others (the Contractor or Owner) or may be done by the flooring contractor at additional cost to the work.
.02 It shall also be the responsibility of the flooring contractor to ensure that environmental and substrate conditions are in accordance with minimum NFCA and floor covering manufacturer's recommendations. Unless otherwise noted in this publication or specified by the flooring material manufacturer the following conditions shall be provided:
- The area of Work temperature shall be between 18°C and 29°C (65°F to 85°F).
- The substrate temperature shall be not less than 16°C (60°F).
- The relative humidity of the Work area shall be between 35% to 55%.
- These conditions shall be controlled and maintained for at least 48 hours before, during, and 48 hours after the installation of flooring materials.
.03 The flooring contractor shall not be responsible for the condition of the substrate or for any corrective work undertaken or contracted by the Contractor that may at a later time adversely affect the performance or appearance of the floor covering and /or installation.
.04 Floor covering work shall not commence where there is an indication of moisture or hydrostatic pressure or excess alkalinity. Due to the sensitivity of some flooring types to moisture or alkalinity, all concrete floors shall be tested as previously noted.
.05 Floor covering work shall not commence until all unsatisfactory conditions have been corrected. Any unsatisfactory conditions or defects likely to impair finished work shall be reported in writing to the Owner or Contractor. Commencement of work shall not imply acceptance of surfaces and conditions, except as qualified herein.
18 • HOARDING
.01 The contractor shall provide hoarding as necessary to maintain stable indoor environmental conditions in accordance with the specified flooring and related product manufacturers installation/warranty requirements.
- Two layers of fire rated 6-mil plastic.
- Damage, punctures, tears should be repaired within 8 hours.
- The hoarding system as a whole should be well-constructed, with no, gaps, tears, holes or loose sheets.
- Re-sealable (zipper) doors are recommended.
19 • VAPOR RETARDERS
.01 Moisture vapor moves through materials naturally. The more porous a material is, the easier it is for moisture vapor to diffuse through it. The function of a vapor retarder is to control the entry of moisture vapor in and out of building assemblies. Protection against moisture involves utilizing moisture control systems through the entire building construction design, from the exterior of the building to the interior building envelope
A properly designed building, and quality construction practices, protect the interior living space against the infiltration of moisture, and the effects of seasonal humidity and temperature fluctuations between the inside and outside of the structure.
A properly designed building, and quality construction practices, protect the interior living space against the infiltration of moisture, and the effects of seasonal humidity and temperature fluctuations between the inside and outside of the structure.
.02 Description of Terms
Vapor Permeance: A property that describes the ease with which vapor molecules diffuse through a material. More specifically, vapor permeance is defined as the quantity of vapor flow across a unit area that will flow through a unit thickness under a unit vapor pressure difference.
Perm Rating: The standard measure of the water vapor permeability of a material. The higher the number, the more readily water vapor can diffuse through the material. Vapor Retarder (also known as a vapor diffusion retarder): A layer of material that is used to control the rate at which moisture can move through a material. |
.03 Vapor Retarder Classifications
The International Residential Code describes three classes of Vapor Diffusion Retarders (Class I, Class II, and Class III when tested in accordance with ASTM E-96 Test Procedure A — the desiccant or dry cup method):
A. Class I vapor retarder ≤0.1 perm. Class I vapor retarders are also considered Vapor Impermeable Membranes or Vapor Barriers.
B. Class II vapor retarder >0.1 perm and ≤1.0 perm. Class II vapor retarders are also considered Vapor Semi-Impermeable Membranes. C. Class III vapor retarder >1.0 perm. Class III vapor retarders are also considered Vapor Semi-Permeable Membranes. |
.04 Vapor Retarders over concrete substrates
- In on- and below-grade applications, due to the ever-changing moisture variability with a concrete slab, and the likelihood of sub-slab moisture barrier degradation over time, a Class I impermeable vapor retarder is always recommended.
.05 Vapor Retarders over Wood Subfloors
- IMPORTANT: Never use a vapor retarder over a wood subfloor to remedy a known moisture condition, and never install flooring over a known moisture condition.
END OF SECTION A10