Revision 04 - December 2020
A12 - SUBSTRATE PREPARATION
A12-1 General Requirements
A12-2 Basic substrate requirements
A12-3 Preparing wood substrates
A12-4 New concrete substrates
A12-5 Concrete subfloors requiring special surface preparation work
A12-6 Preparing existing resilient flooring surfaces
A12-7 Removal of resilient flooring
A12-8 Preparing concrete surfaces containing residual adhesive
A12-9 Preparing metal surfaces
A12-10 Preparing poured polymeric and/or epoxy surfaces
A12-11 Preparing existing terrazzo/marble/ceramic surfaces to receive resilient flooring
A12-2 Basic substrate requirements
A12-3 Preparing wood substrates
A12-4 New concrete substrates
A12-5 Concrete subfloors requiring special surface preparation work
A12-6 Preparing existing resilient flooring surfaces
A12-7 Removal of resilient flooring
A12-8 Preparing concrete surfaces containing residual adhesive
A12-9 Preparing metal surfaces
A12-10 Preparing poured polymeric and/or epoxy surfaces
A12-11 Preparing existing terrazzo/marble/ceramic surfaces to receive resilient flooring
Spec note definition:
Subfloor, - that structural layer intended to provide support for design loadings which may receive resilient floor coverings directly the surface is appropriate or indirectly via an underlayment if its surface is not suitable.
Substrate: the underlying support surface upon which the floor covering is installed.
Subfloor, - that structural layer intended to provide support for design loadings which may receive resilient floor coverings directly the surface is appropriate or indirectly via an underlayment if its surface is not suitable.
Substrate: the underlying support surface upon which the floor covering is installed.
1 • GENERAL REQUIREMENTS
|
2 • BASIC SUBSTRATE REQUIREMENTS
.01 All substrates surfaces must be dry, relatively smooth, level and free from irregularities or imperfections that may potentially be telegraphed to the surface of the newly installed flooring and thereby detract from the final appearance and possibly impair the longevity of the flooring.
.02 The substrates must be free of any previous surface applications, such as wax, oil, paint, varnish, hardening compounds, old adhesive, etc., that will impair the adhesive bond, or cause staining. .03 Existing substrate surfaces must be correctly prepared to provide an acceptable surface and bond for the replacement flooring. .04 Various substrates surfaces may be covered with flooring materials, subject to NFCA acceptance. Some of these are: |
|
3 • PREPARING WOOD SUBSTRATES
.01 Refer to General Requirements. 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.
|
.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 as underlayment grade for use by flooring material manufacturer. Such material must be installed in strict accordance with Building Code and the floor covering material manufacturer's requirements. .05 Wood subfloors should be standard double-layer construction with a finished thickness of at least 1". .06 Additional layer of sheathing over non-compliant subfloors to receive wood flooring:
|
Note: Floor Covering Manufacturers do not recommend the installation of resilient flooring over wood panels attached directly to on grade or below grade concrete slabs or over sleeper constructed subfloors on or below grade concrete slabs. Refer to Part A10 - Acceptable Conditions for wood substrate requirements.
Note: The installation of an approved wood panel underlayment over strip or plank flooring will minimise the potential telegraphing effect and compensate for the seasonal expansion and contraction characteristics of the boards and is therefore strongly recommended. Refer to Part A10 - Acceptable Conditions and Part D06 (Hardwood) Installation Guide for further explanation and requirements. |
.02 Basic Preparation Requirements:
|
.1 Strip and Plank Floors: Any loose and squeaky boards must be securely nailed and all broken or unsound boards or board sections replaced. The entire flooring should be sanded until even and sealed to prevent moisture absorption. Cracks in excess of 1.6 mm between boards should be filled level.
.2 Underlayment Panels: The following types of panel materials are acceptable depending on floor covering material to be applied, floor covering manufacturers recommendations and pre-approval, NFCA requirements, and panel manufacturer’s |
Refer to Part A10 - Acceptable Conditions for wood substrate requirements. |
.03 Basic Underlayment Panel Preparation Requirements:
|
|
4 • NEW CONCRETE SUBSTRATES
.01 Basic Substrate Requirements:
|
|
.01 Basic Preparation Requirements:
|
|
|
3. Refer to Part A13 - Patching and Filling for recommended patching / levelling compounds and for General Contractor and Flooring Contractor responsibilities.
|
.03 Preparing Hydraulic Cementitious Underlayment Surfaces:
|
|
5 • CONCRETE SUB-FLOORS REQUIRING SPECIAL SURFACE PREPARATION WORK
.01 Treating an Alkaline Condition:
|
|
.02 Concrete Curing / Sealing Agents and Removal:
|
|
|
3. Special Note: Due to the large number of curing and/or sealing compounds available, specific recommendations cannot be made regarding their use or need for removal. Specifiers and Contractors must therefore ensure that the products selected are recommended by the curing / sealing compound manufacturer for the type of floor covering and/or installation system specified.
The responsibility for concrete sealer and curing warranties rests with the concrete treating compound manufacturer / supplier / specifier or building contractor / owner in the event of a flooring and/or installation failure and not with the floor covering manufacturer, supplier, or floor covering contractor. |
.03 Removal of Concrete Substrate Surface Treatments:
|
|
|
.04 Preparing Hard-Trowelled Concrete Substrate Surfaces:
|
|
|
.05 Preparing Coloured Concrete Substrate Surfaces:
|
|
.06 Preparing Painted Concrete Substrate Surfaces:
|
|
4. Special Note: The remaining paint must be well bonded to the concrete surface, as any remaining loose paint will lift once covered with flooring, resulting in buckling, edge peaking, or other flooring problems. Be aware, some flooring lines cannot be installed over painted surfaces. Check with floor covering manufacturers for the types of flooring that can not be installed over painted surfaces.
|
.07 Preparing Existing Terrazzo / Marble / Ceramic Tile Surfaces:
|
|
.08 Preparing Oil / Grease / Wax Contaminated Monolithic Surfaces:
|
|
6 • PREPARING EXISTING RESILIENT FLOORING SURFACES
.01 In general, floor covering manufacturers recommend complete removal of resilient flooring prior to any new flooring installations.
.02 Those manufacturers that endorse installations over existing resilient flooring impose certain limitations. These include: |
|
Note: For complete information regarding the suitability of products and installation procedures over existing resilient flooring contact floor covering manufacturers.
|
.03 Basic Surface Preparation Procedures:
|
|
7 • REMOVAL OF RESILIENT FLOORING
.01 To avoid dimensional instability, excessive indentation or bonding problems with the replacement flooring, the existing resilient flooring regardless of type or condition should be removed.
.02 The removal of the old flooring and the required preparation work is generally very time consuming and often will take longer than the replacement installation. .03 Although many different devices are used to remove resilient flooring, no efficient method has been developed by floor covering contractors that will work satisfactorily under all conditions. .04 The actual method of removal selected will depend on the location of the flooring and the familiarity with the removal procedure of the individual contractor. The selected method of removal must also comply with NFCA requirements, the new floor covering manufacturers recommendations, and applicable WCB requirements. .05 Removing Resilient Floor Tiles:
|
8 • PREPARING CONCRETE SURFACES CONTAINING RESIDUAL ADHESIVE
.01 In accordance with the manufacturers recommendations, remaining adhesives residues must be removed or sealed, prior to any new flooring installation.
.02 In accordance with the prevailing work practices: |
.1 Non-asphaltic adhesive residue that is compatible with the replacement adhesive and flooring materials may remain providing that the remaining adhesive residue is reduced to a thin, smooth even film. Adhesive bond tests must be conducted prior to any new flooring installation.
.2 Asphaltic-based adhesive residue must be removed or sealed prior to any new flooring installation, except when installing vinyl composition tile (VCT). If VCT flooring is to be installed the adhesive residue must be reduced to a thin, smooth even film. |
.03 Basic Asphalt Adhesive Removal Procedures.
|
.1
Removal
may be accomplished by wet grinding / sanding, using floor polisher with
plastering-lath wire attachment, concrete or terrazzo grinder.
.2 Shot blasting area (a very effective removal procedure). .3 Using chemical adhesive removers. Caution: Most chemical adhesive removers are flammable and/or toxic; therefore, their use may be restricted. .4 Special Note: The use of solvents to remove asphalt-base adhesives is not recommended. Solvents tend to carry adhesive residues deeper into the surface of concrete slabs; thereby causing bond failures and potential staining of newly installed flooring. |
.04 Applying Coatings and/or Mastic Sealers Over Adhesive.
|
.1 There are a number of manufacturers that are marketing trowelable, high bond strength, polymer modified Portland cement base sealing compounds that are recommended for the direct installation over asphalt base adhesives.
.2 To prevent adhesive migration discolourations and to insure proper bond, these types of coatings must be applied in strict compliance with the manufacturer’s recommendations. .3 Basic Application Procedure: |
.a Following
tile removal, the remaining adhesive residue must be reduced to a thin, smooth,
even film. Signs of adhesive flaking or
breakdown will warrant complete adhesive removal.
.b Sealing compound must be mixed and applied in compliance with manufacturers recommendations. .c Sealing compound should be applied even, level with no ridges or gaps showing. .d Coverage must be 100 percent with no signs of adhesive residue showing. .e Allow for adequate drying time before starting with new installation. |
.4 Precautions:
|
.a Gypsum
based patching compounds applied directly over asphalt base adhesives are not
recommended. The bond of these types of
patching compounds is generally inadequate, and they break up from the force of
surface loads and will not seal-out adhesive migration actions.
.b Encapsulating liquid sealers or liquid latex applied directly over asphalt base adhesives are not recommended. |
.5 Gypsum based patching compounds applied directly over asphalt base adhesives are not recommended. The bond of these types of patching compounds is generally inadequate, and they break up from the force of surface loads and will not seal-out adhesive migration actions.
.6 Encapsulating liquid sealers or liquid latex applied directly over asphalt base adhesives are not recommended. |
9 • PREPARING METAL SURFACES
.1 Occasionally metal subfloors may be encountered such as on ships, raised metal floors, walkways, landings, etc. that necessitate the use of floor covering. These areas will require the utmost care in all aspects of preparation work. Forces that effect metal floors differently are:
|
|
.2 Preparation Recommendations
|
|
10 • PREPARING POURED POLYMERIC AND/OR EPOXY SURFACES
.1 Polymeric and epoxy surfaces must meet the following conditions:
|
|
.2 Preparation Recommendations:
|
.1 Areas should be dry/wet sanded until smooth, using floor polisher with disk attachment, drum sander or any other suitable equipment.
.2 Old remaining floor finishes should be wet-stripped and thoroughly cleaned. .3 Allow areas to dry before taking any further action. .4 Surface defects should be spot patched. Skim coating of entire area is not recommended, as patching material may not adhere reliably. .5 An adhesive bond test is recommended prior to any flooring installation. |
.3 Preparation Recommendations:
|
Special Note: The responsibility for determining if the existing polymeric or epoxy flooring is well bonded to the existing substrate and that the remaining surface texture is sufficiently smooth not to impede the final appearance, rests with the floor covering contractor. The flooring installer is advised to secure a disclaimer from the Owner / Consumer in regard to potential texture telegraphing and/or delamination problems of existing flooring, prior to new flooring installation.
|
11. PREPARING EXISTING TERRAZZO / MARBLE / CERAMIC SURFACES TO RECEIVE RESILIENT FLOOR COVERINGS
.1 Remove dust, wax, paint, oil, grease or any other foreign substance from the surface.
.2 Remove loose tiles and wash the substrate with a tri-sodium phosphate (TSP) solution and rinse until clean. .3 Glazed tiles or very smooth surfaces should be abraded, using concrete grinder. Grouted joints and any other worn or low areas should be filled and leveled using industry approved patching /leveling compound. .4 All preparation work shall comply with the adhesive, cementitious underlayment or floor covering manufacturers installation guid |
END OF PART A12