Revision 01- 16 July 2018

AA2 - SPECIFICATION GUIDE 03 54 12 - GYPSUM UNDERLAYMENT

AA1-1 General
AA1-2 Products
AA1-3 Execution
Preface:
  1. Refer to Part A16 – Specification Guides before using this specification.
  2. Use this specification guide when a dimensionally stable, self-levelling, pre-blended gypsum cement t is required over substrate surfaces to provide an acceptable surface for the installation of NFCA finish flooring materials.Other finish flooring materials (e.g. tile and terrazzo) may have different requirements.Note:Acceptable substrate surfaces must be verified by the underlayment manufacturer before specifying this type of underlayment material.
  3. If a hydraulic cement underlayment is required use Section 03 54 16.
  4. This Section including Section references noted under Related Work Specified Elsewhere is for the most part based on the MasterFormat 2016 Section numbering system.  Text numbering in NFCA specifications however does not comply with PageFormat numbering system.
  5. This specification is directed to the (General) Contractor (or Construction Manager).Where there is no General Contractor substitute the term Flooring Contractor.
  6. Review all requirements noted herein and carefully choose those that meet project requirements.The Specifier must choose one item from a series of items surrounded with [] brackets such as [Contractor] [Construction Manager] [Consultant] and delete the remainder.Items surrounded with() brackets are additional information / comments that should be left in the specification.
  7. Adding or deleting items in this specification must be done with care and caution.The onus of doing so rests with the Specifier who must have a complete and thorough understanding of what is required. Where additional information must be added to this specification the Specifier must ensure that such information is not only accurate but also in accordance with NFCA requirements.Because of the above noted requirements NFCA strongly recommends that this specification be edited by a qualified specification writer.Refer to Part A16 - Specification Guides, 1.02.
  8. Parts of this specification are not auto-numbered.Any changes (additions or deletions) therefore means that the specifier will have to re-number / re-space following items to suit.
  9. Revise header (including total pages) and footer to suit project requirements.As a suggestion insert project name particulars on left side of header and consultant name on bottom left and issue date on bottom right of the footer.
  10. Remove these Preface notes and all Spec Notes after editing this specification for a project.
1 • GENERAL

.01 Description:
SPEC NOTES:
  1. This article (1.1) is not intended to scope gypsum cement underlayment work but to serve as a general description.The onus of defining the extent of this section of Work remains with the Contractor, who will ensure that the area / scope of responsibility of any particular Subcontractor / supplier is set out in full detail when awarding the contract for this work.The extent of this section of Work is also governed by the limits of local trade agreements and conditions.This article should be used in conjunction with Related Work.
  2. This work shall be provided by the General Contractor or by the flooring contractor under a separate contract or separate price.Refer to Part A12 - Substrate Preparation, Part A13 - Patching and Filling, and Part A16 - Specification Guides for information.
  3. Gypsum based underlayments shall not be used in exterior locations, below grade or where continuous exposure to moisture is likely.
  4. Gypsum based underlayments shall not be used as a wear surface and must be covered by a finished floor covering.
  5. The floor structure below gypsum cement underlayments shall be designed so that deflection does not exceed a live or dead load of L/360.Certain floor coverings, such as marble, limestone, travertine and wood, may have more restrictive deflection limits.
  6. All substrate materials and conditions shall be acceptable to underlayment manufacturer.Consultant shall review same prior to writing / issuing underlayment specifications before issuing for bidding.
.1         Section Includes:  All labour, materials, equipment, and services to supply and install a self-levelling, non-shrinking, fully bonded, pre-blended /engineered gypsum cement underlayment over acceptable substrate surfaces, as required to achieve an acceptable flat and level, crack-resistant surface suitable for the installation of NFCA finish flooring materials by others.
.2         The provision of gypsum cement underlayment shall be based on a Fixed Price for the installation of 10 mm (3/8”) of underlayment and a Unit Price 035412-U1 for each additional cubic metre of underlayment required to accommodate substrate deflection and other irregularities in the substrate surface to provide a suitable level surface for the application of specified flooring materials.
SPEC NOTE:    Re above - Refer to Part A16 - Specification Guides for information.  Note that such Unit Pricing is indicated using the Section number as an aid to listing such pricing in a numerical order on the Bid Form.  Specifiers may choose an alternate method.

SPEC NOTE:    Use the following items .3 and .4 only as required.  Clauses may be revised to suit specification and/or form of Contract conditions as required.
.3         This Section along with the drawings forms part of the Contract and is to be read, interpreted, and coordinated with all other parts.
.4         Division 00 - Procurement and Contracting Requirements and Division 01 - General Requirements form an integral part of this Section of Work.
.5         Related Work Specified Elsewhere:  shall include, but not necessarily be limited to, the following:
SPEC NOTE:    This lists work related to this section but not to be included as part of this section.  Delete, revise, or add to example sections listed below as required.  Coordinate items with other Sections of Work in the Project Manual.  This is not a comprehensive list.  Refer to CSC MasterFormat for up-to-date Section numbers and amend as required and Guide specifications for numbers.  All relevant Sections should be noted under each Division
Section 02 40 00     Demolition / Alterations (removal / disposal of existing floor finishes)
Section 02 42 10     Removal of Existing Flooring
Section 02 82 00     Facility Remediation (hazardous material removal)
Section 03 30 00     Cast-in-Place Concrete (slab finishes)
Section 06 10 00     Rough Carpentry (floor framing and sheathing)
Section 07 92 00     Caulking and Sealants
Section 07 95 00     Expansion Joints (floors)
Section 09 62 19     Laminate Flooring
Section 09 64 00     Hardwood Flooring
Section 09 65 00     Resilient Flooring
Section 09 68 00     Carpet Flooring
Division 23              Heating, Ventilation, and Air Conditioning (floor grilles, etc.)
Division 26              Electrical (floor outlets, floor boxes, site grounding, etc.)
1.2        Reference Standards:
.1         The latest applicable edition of the Floor Covering Reference and Specification Manual issued by the National Floor Covering Association of Canada (NFCA) shall govern all materials and workmanship.  Whenever reference is made within this specification to NFCA requirements it shall mean, as a minimum, those standards and requirements noted in the NFCA Reference and Specification Manual.
.2         The latest applicable edition of the following additional reference standards shall also govern all materials and installation work specified herein as applicable:
CAN/CSA A23.1-14/A23.2-14, Concrete materials and methods of concrete construction / Test methods and standard practices for concrete.
ASTM C109/C109M-16, Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (using 50 mm [2”] Cube Specimens).
ASTM C317 / C317M-00 (2015), Standard Specification for Gypsum Concrete.
28 day compressive strength ASTM C472-99 (2014), Standard Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum Concrete.
ASTM C348, Standard Test Method for Flexural Strength of Hydraulic-Cement Mortars.
ASTM C472, Standard Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum Concrete.
ASTM E84, Standard Test Method for Surface Burning Characteristics of Building Materials.
ASTM E1155, Standard Test Method for Determining FF Floor Flatness and FL Floor Levelness Numbers.
ASTM F710, Standard Practice for Preparing Concrete Floors to Receive Resilient Flooring.
ASTM F2419, Standard Practice for Installation of Thick Poured Gypsum Concrete Underlayments and Preparation of the Surface to Receive Resilient Flooring.
ASTM F2471, Standard Practice for Installation of Thick Poured Lightweight Cellular Concrete Underlayments and Preparation of the Surface to Receive Resilient Flooring.
ASTM F2659, Standard Guide for Preliminary Evaluation of Comparative Moisture Condition of Concrete, Gypsum Cement and Other Floor Slabs and Screeds Using a Non-Destructive Electronic Moisture Meter.
ASTM F2678, Standard Practice for Preparing Panel Underlayments, Thick Poured Gypsum Concrete Underlayments, Thick Poured Lightweight Cellular Concrete Underlayments, and Concrete Subfloors with Underlayment Patching Compounds to Receive Resilient Flooring.
ASTM F2873, Standard Practice for the Installation of Self-Leveling Underlayment and the Preparation of Surfaces to Receive Resilient Flooring.
Workplace Hazardous Materials Information System (WHMIS).
SPEC NOTE:    When gypsum underlayment is a component of a fire rated and/or an acoustical rated assembly over wood subfloor assemblies include the following reference standards.
CAN/ULC S102-10, Method of Test for Surface Burning Characteristics of Building Materials and Assemblies.

For acoustical rated floor assemblies:
ASTM E90, Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements.
ASTM E336, Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings (for Field Sound Transmission Class (F-STC).
ASTM E492, Standard Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using the Tapping Machine (for Impact Insulation Class (IIC).
ASTM E1007, Standard Test Method for Field Measurement of Tapping Machine Impact Sound Transmission Through Floor-Ceiling Assemblies and Associated Support Structures (for Field Impact Insulation Class (F-IIC).
ASTM E2179, Standard Test Method for Laboratory Measurement of the Effectiveness of Floor Coverings in Reducing Impact Sound Transmission Through Concrete Floors.
1.3        Design Criteria:
  1. Gypsum cement underlayment shall be plant mixed or site mixed from pre-mixed bag or hopper material only providing strengths, air content, and slump as noted herein in accordance with requirements of noted Reference Standards.All pre-mixed bag materials shall be delivered in their original unopened packages and protected from damage and exposure from the elements.  Damaged or deteriorated materials shall be removed from the premises.  Site mixing of separate ingredients will not be permitted.  Note that light weight, low compressive strength, and site mixed gypsum cement underlayments using site mixed ingredients are not permitted.
  2. All components of gypsum cement underlayment shall be inorganic and shall provide no source of nutrients to sustain mould growth.
  3. Gypsum cement underlayment shall achieve minimum compressive and flexural strengths as specified herein, be capable of being walked on after 3 hours without damage, and be capable of being covered after 24 hours at 21oC (70oF) after acceptable bond and mat testing results.
  4. Gypsum cement underlayment shall be installed in one pour to a minimum nominal thickness of 10 mm (3/8”) and to a minimum thickness of 3 mm (1/8") over the highest point of a substrate surface or where it is feather edged or tapered in order to match existing elevations without fracturing or spalling.
  5. If installed on wood subfloors above a crawl space, subfloor assembly must be protected by a vapour barrier.
  6. If installed in conjunction with radiant heated floors consult / coordinate with radiant heating system manufacturer for installation requirements.
  7. Comply with CAN/ULC S102-10 tested assembly requirements for fire rated flooring assemblies.
  8. For acoustically rated flooring assemblies, provide materials and construction identical to those tested in assembly indicated, according to ASTM E90 and classified according to ASTM E413 by an independent testing agency.
SPEC NOTE:    When gypsum cement underlayment is a component of a fire rated flooring assembly include point #7:
SPEC NOTE:    When gypsum cement underlayment is a component of an acoustical rated flooring assembly include point #8:
1.4        Quality Assurance
  1. Both the manufacturer and installer of gypsum cement underlayment shall have a minimum of five years experience of manufacturing and installing underlayment products.
  2. All work shall be done by skilled applicators thoroughly experienced in the installation of gypsum cement underlayment using mixing equipment and tools approved by the manufacturer and with applicators wearing appropriate foot wear to avoid leaving marks in the liquid mixture.
  3. Before, during, and after installation of the application area shall be enclosed (roofs, windows, doors, and any other apertures) and provided with adequate ventilation and heat to maintain ambient and substrate temperatures above 10o for to allow for drying of .
  4. Do not install gypsum cement underlayment if substrate and ambient air temperatures are below 10oC (50oF) or above 25oC (77oF) unless otherwise site approved by product manufacturer and only then following manufacturer’s precautions.
1.5        Site Meeting:
.1       Before installing gypsum cement underlayment on site, the General Contractor, underlayment placing and finishing Subcontractor, finish flooring Subcontractors, and the Consultant shall meet to discuss the following items:
.1 Review of substrate type, compatibility, and conditions as well as environmental requirements for the installation of gypsum cement underlayment.
.2   Review of finishing requirements to achieve flatness and levelness requirements for finish flooring as noted herein including localized slopes to floor drains and trenches.
.3   Review of flooring finishes by others and their installation requirements including moisture testing of concrete and provision of written results.
.4   Requirements for installation of gypsum cement underlayment over radiant heating system.
.5   Inspection procedures and reports
1.6        Material Testing:
.1         Provide samples of gypsum cement underlayment for testing purposes.  This shall consist of taking an entire unopened bag of the product being installed to an independent testing facility to perform compressive strength testing in accordance with ASTM C109 / modified: air-cure only.  Note that there are no in-situ test procedures for the evaluation of compressive strength.
.2         If any gypsum cement underlayment is not in accordance with these specifications or the noted reference standards, the material shall be removed and replaced with material meeting requirements at no cost to Owner.  The decision of the Consultant in this regard shall be final and binding upon the parties to the Contract.
1.7        Submittals:
.1         All submittals shall be in accordance with the requirements of Section 01 30 00.
.2         Submit letter of certification from supplier of cementitious underlayment verifying compliance to design requirements specified herein, stating strengths and composition.
SPEC NOTE:    Use the following if required by Consultant.
1.8        Mock-Up:
.1         Provide a mock-up of underlayment installation in a location designated by the Consultant for evaluation of surface preparation techniques and application workmanship.
.2         Do not proceed with remaining work until workmanship is approved by the Consultant.
.3         If required, refinish mock-up area as required to produce acceptable work.
1.9        Product Delivery, Handling, and Storage:
.1         Deliver, store, handle, and mix all gypsum underlayment materials in strict accordance with manufacturers written requirements using packaged materials labeled with product identification, manufacturer, batch number, and shelf life.
.2         Protect all materials from extreme temperatures and moisture and protect all liquids from freezing.
PART 2 - PRODUCTS
2.1 Materials (Select appropriate Components)
.1         Saw Cut and Control Joint Filler:  material as recommended by underlayment manufacturer for filling of all non-moving joints in concrete.  An Engineer or Consultant shall determine if a joint is moving or non-moving.
.2         Primer (over substrates):  to suit substrate type and in accordance with gypsum cement underlayment manufacturers requirements.
.3         Acoustical Membrane for Acoustically Rated Assemblies:  sound deadening material engineered to limit impact noise transmission complete with appropriate joint tape in accordance with tested assembly requirements and noted underlayment manufacturer’s materials.
.4         Waterproof Membrane:  moisture impervious material complete with appropriate joint tape to prevent moisture penetration as recommended by underlayment manufacturer.
.5         Tape or Quick-Setting Patching Compound:  material as recommended by underlayment manufacturer.
.6         Underlayment Crack Suppression / Reinforcement:  water / rust resistant material as recommended by underlayment manufacturer.
.7         Gypsum cement underlayment:  high early strength self-levelling inorganic gypsum cement mixture consisting of gypsum plaster, Portland cement,  plasticizer, rheology modifier, defoamer and a set modifier as recommended by manufacturer meeting the following requirements:
             .a   minimum 28 day compressive strength to ASTM C472 of 20.6 MPa (3000 psi).
             .b   minimum 28 day flexural strength to ASTM C348 (air cure only) of 5 MPa (725 psi).
.8         Aggregate:  well graded (#8 to #100 sieve) and washed plaster or masonry sand in accordance with gypsum cement underlayment manufacturer’s requirements.
.9         Water:  clean, impurity free, potable, and sufficiently cool (not warmer than 21oC (70oF).
.10        Underlayment Surface Sealer:  type if and as recommend by gypsum cement underlayment and compatible with finish flooring adhesive and materials.
SPEC NOTE:    Include point #3 if gypsum cement underlayment with an integral acoustical separation membrane is a component of an acoustical rated flooring system.  Refer to tested assembly requirements and noted underlayment manufacturer’s materials.
SPEC NOTE:    Include point #4 if the gypsum cement underlayment requires the installation of a waterproof membrane and tape / patching compound over existing gypsum substrates, over wood flooring, or over a substrate susceptible to damage from moisture ingress.  Refer to underlayment manufacturer for material recommendations.
SPEC NOTE:    Use point #10 when recommended by underlayment manufacturer.
2.2        Gypsum Cement Underlayment Mix:
.1         Provide plant mixed or site mixed from pre-mixed bag or hopper material only in strict accordance with 1.3 Design Requirements using materials, quantities, water, and mixer / paddles required by manufacturer to obtain a lump-free mixture.  Unless otherwise approved by the manufacturer do not over mix, slake, let stand, or re-temper.
.2         Test compressive strength in accordance with ASTM C472M.
.3         For pump installations mix gypsum cement underlayment using manufacturer’s recommended pump ensuring not to over-water mix.
.4         Check consistency of gypsum cement underlayment installed on substrate to ensure a uniform distribution of mix at both the top surface and bottom of the pour.  If settling is occurring, reduce the water amount and recheck.  Conditions during the installation, such as variations in water, underlayment mix, substrate, and ambient temperature, require that the water setting be monitored and adjusted carefully to avoid over-watering.
PART 3 - EXECUTION
3.1        Preparation:
SPEC NOTE:    Verify substrate suitability and compatibility with gypsum cement underlayment manufacturer.  Unless otherwise pre-approved by the manufacturer gypsum cement underlayment shall not be used over hardwood flooring, masonite, chipboard, flakeboard, presswood, asbestos board, lauan plywood, oriented strand board (OSB), metal, or other similarly unstable substrates.
  1. All substrates shall be adequate to withstand live and dead loads with a deflection limitation of L/360.The installation of gypsum cement underlayment shall not proceed over concrete substrates until slab deflection has stabilized to the extent that no further deflection takes place.
  2. All concrete and wood substrate surfaces must be structurally sound and be of adequate strength to support the additional weight of underlayment, and shall be clean, dry, and free of all laitance, oil, grease, curing compounds, and dust/dirt before arrival of the gypsum cement underlayment applicator.  Any substance which might act as a bond breaker must be removed before priming.  For concrete substrates this may mean using mechanical means if necessary such as shot-blasting, scarifying, or any other appropriate method.  Acid etching and the use of sweeping compounds and solvents are not acceptable.
  3. Wood substrates shall be NFCA approved nominal 19 mm (3/4”) T & G subfloor sheathing that is securely fastened with screw fasteners, particularly at abutting sheathing joints.
  4. Mechanically fasten existing wood substrate loose boards and panels to eliminate substrate movement and squeaks.Sand to remove coatings that might impair underlayment bond and remove sanding dust.
  5. Mechanically remove rust, foreign matter, and other contaminants from metal substrate surfaces that might impair underlayment bond according to manufacturer's written instructions.Apply corrosion-resistant coating compatible with underlayment if recommended in writing by underlayment manufacturer.
  6. Remove waxes, sealants, and other contaminants from existing ceramic tile, quarry tile, and terrazzo substrates that might impair underlayment bond and prepare surfaces according to underlayment manufacturer's written instructions.
  7. Prior to installation of gypsum cement underlayment the General Contractor (GC) shall inspect and approve the condition of all substrates and test all surfaces for moisture, porosity, or any other conditions that could affect the performance of gypsum cement underlayment.
  8. Perform moisture testing on concrete substrates and proceed with installation only after substrates do not exceed a maximum moisture-vapor-emission rate of 2.27 kg of water per 92.9 sq. m (5 lbs of water per 1000 sq. ft) in 24 hours.
  9. Open, clean, and repair all cracks in substrates to minimize telegraphing through gypsum cement underlayment.Fill cracks, voids, and openings in wood subfloors where leakage of gypsum cement underlayment slurry could occur.
  10. Fill all non-moving saw cuts and control joints in concrete substrates using specified materials.
  11. Provide moving expansion and isolation joints through gypsum cement underlayment to suit requirements of such joints in substrates.
  12. At acoustically rated floor assemblies install isolation strips at room perimeters, around columns and other floor penetrations, and at doorways and acoustical separation membrane in strict accordance with membrane manufacturer’s requirements.
  13. Fill all cracks and voids in wood subfloor with a quick-setting patching or taping compound where leakage of underlayment could occur.
  14. Where applicable, install waterproof membrane over wood subfloors in strict accordance with membrane manufacturer’s requirements.
  15. Remove, correct, or suitably prime all substrate surfaces or finishes that will impair bonding of underlayment before installation.
  16. Prime wood and concrete substrates using materials, procedures, and application rates in accordance with gypsum cement underlayment requirements.Apply material evenly using primer manufacturers recommended applicators and do not leave any bare spots.Remove all puddles and excess primer and allow to dry to a clear, thin film (minimum of 3 hours to a maximum of 24 hours).Do not install gypsum cement underlayment until primer is dry.
  17. Prime extremely absorbent substrates using materials and methods in accordance with manufacturer’s requirements, leaving no bare spots.Remove all puddles and excess primer and allow to thoroughly dry before proceeding with the standard application of primer as described above for standard absorbent surfaces.
3.2        Installation:
  1. Schedule all work with respect to other trades.
  2. Review substrate conditions and acceptability before proceeding with gypsum cement underlayment installation and ensure all preparation requirements noted in Section 3.1 above have been met.
  3. Where gypsum cement underlayment is part of a fire and/or acoustical rated assembly ensure that installation of underlayment materials conform to the tested assembly requirements.
  4. Pour or pump self-levelling gypsum cement underlayment over substrate surfaces at locations required and spread material using tools and methods recommended by manufacturer to provide a level surface for floor finishes.
  5. For thick single pours or where gypsum cement underlayment is installed in two pours, reinforce the first layer using aggregate or underlayment reinforcing as recommended by underlayment manufacturer.
  6. Coordinate application of components to provide optimum adhesion to substrate and between pours.
  7. Place gypsum cement underlayment as continuously as possible until installation is complete so that no slurry is placed against underlayment that has obtained its initial set, except at authorized joints.
  8. At substrate expansion, isolation, and other moving joints, allow joint of same width to continue through underlayment.
  9. Screed material to correct slopes and levels to provide slopes to drains and feather edge where indicated or required.
  10. Finish gypsum cement underlayment surface in accordance with CAN/CSA-A23.1 to provide a smooth, level, monolithic surface, free of defects and blemishes to suit flooring requirements as noted herein and/or as required by flooring subtrade.
  11. Apply specified sealer to gypsum cement underlayment at 0.5 mm (20 mils) or less.Sealer shall be thoroughly dried before surface traffic can proceed.
  12. Do not install floor coverings over underlayment until after time period recommended in writing by underlayment manufacturer.
  13. Remove and replace underlayment areas that evidence lack of bond with substrate, including areas that emit a "hollow" sound when tapped.
3.3        Protection:
  1. Protect work and close traffic to all areas, maintain temperature and humidity required until gypsum cement underlayment has cured and is ready for normal traffic.
  2. During construction, place temporary wood planking over gypsum cement underlayment wherever it will be subject to heavy wheeled or concentrated loads.
  3. The GC shall not place concentrated loads such as pallets of material, drywall, taping compounds or any heavy items, which may cause deflection, in the middle of the floor.
  4. Prior to the installation of the finish flooring, protect surface of underlayment from abuse by other trades by use of plywood, hardboard, or other suitable protection course.
END OF SECTION