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Double Plywood Floor System Combined with Synthetic Flooring

Part 1-General


  1. This document specifies combination gymnasium floor systems consisting, in general, of maple parquet or strip flooring, synthetic flooring, wood subflooring, vapor barrier, sanding, sealers, finishes, game lines and wall base.
  2. The general contractor shall provide a concrete slab, smooth and level to a tolerance of 1/8” in a 10’ radius, subject to the approval of the flooring contractor.

    F-Numbers are not applicable for gymnasium slab applications. Labor and materials necessary to put the concrete slab in acceptable condition (high areas ground down and low areas filled with appropriate leveling compounds) shall be the responsibility of the general contractor. Installation shall not proceed until the concrete slab is in acceptable condition.
    1. The general contractor shall provide slab depressions as per manufacturer’s specifications
    2. Concrete subfloors shall have an adequate moisture barrier beneath and at the perimeter of the slab.
    3. Sand-Poly-Sand slab construction is not acceptable.
    4. Concrete shall be free of washed river gravel, pea gravel, flint or hardener additives.
    5. Concrete shall not be over power troweled or “polished”
  3. The flooring contractor shall provide all tools and services to install a complete combination floor system from the surface vaporproofing of the slab, when required, through the floor system finishing, plus the installation of perimeter base moldings.


  1. The wood flooring shall be MFMA-PQ maple; 3rd party supplied maple shall not be allowed.
    1. OPTION:  MFMA-RL or MFMA-FJ  maple strip flooring
  2. The flooring contractor shall be an MFMA Mill Accredited Installation Company* with MFMA Accredited Installer(s)* on-site for the duration of the wood floor installation.
  3. Flooring shall be delivered to the premises and acclimated, if necessary.
  4. All pallets of flooring should be broken and spread out to acclimate the flooring to environmental conditions in the building, when applicable.


  1. The floor system shall not be delivered or installed until all masonry, plastering/drywalling, tile work and overhead mechanical trades are complete. All finish and/or wet trades, such as, concrete, painting, etc. should be completed and dry prior to delivery to insure proper acclimation of the maple flooring. The building must be enclosed and weathertight.
  2. Permanent heat, light and ventilation shall be installed and operating before, during and after installation, controlling a temperature range of 55 degrees to 75 degrees and a relative humidity range compatible with expected environmental conditions when the facility is occupied. (Maintaining a maximum 15 percent difference between high and low humidity levels). Expected minimum/maximum indoor relative humidity will depend upon building design, geographic location, HVAC systems and operating schedules. Consult your local MFMA Sport Floor contractor for specific information.

1.4      WARRANTY

  1. The MFMA Mill Accredited Installation Company* shall warrant the floor installation, and shall furnish a flooring materials warranty from the flooring manufacturer.
  2. Refer to individual flooring manufacturer’s warranty for specific provisions and exclusions.

Part 2-Material


  1. Wood flooring shall be MFMA-PQ Northern Hard Edge Grain Maple flooring, 5/16"to 7/16" thick panels as manufactured by an MFMA member manufacturer, Second and Better, Third and Better or Third Grade.
    1. OPTION: MFMA-RL or MFMA-FJ Strip flooring; First, Second and Better, Third and Better or Third Grade.
  2. Synthetic flooring shall be supplied by a MFMA Member manufacturer.
  3. Concrete slab surface vapor retarder shall be minimum 6 mil polyethylene film
  4. Subfloor shall be 15/32” x 4’ x 8’, minimum 4 ply, APA (or flooring manufacturers approved rated equivalent) Rated Sheathing, Exposure 1, or per MFMA flooring manufacturer design.
  5. Cushioning shall be supplied and installed per manufacturer’s instructions.
  6. Flooring adhesive shall be as recommended by the flooring manufacturer.
  7. Subfloor fasteners shall be specified by MFMA flooring manufacturer.
  8. Wall base shall be 4” x 3” x 4’ heavy duty molded, vented, rubber or vinyl cove base with premolded outside corners as supplied by flooring manufacturer.
  9. Wood floor finish materials shall be selected from the most recent listing of MFMA tested and certified products approved by MFMA flooring manufacturer and shall be applied according to finish manufacturer’s instructions.

Part 3 - Execution


  1. Inspect concrete slab for proper tolerance and dryness, and report any discrepancies in writing to the general contractor for correction.
  2. The concrete slab shall be cleaned of all debris by general contractor so the accredited installation company will have adequate access to work surface.


  1. Cover entire concrete slab /subbase with surface vapor retarder, lapping joints a minimum of 6” or as specified by the vapor retarder manufacturer. All seams will be sealed together in accordance with maple flooring manufacturer’s installation guidelines.
  2. Install first layer of subfloor plywood opposite the direction of the maple flooring, 1/4” spacing all edges and breaking joints 4’ - Provide 2” expansion voids at perimeter and all vertical obstructions. If required by the flooring system manufacturer, install solid blocking under bleachers in the stacked position and where portable backstops or other areas subjected to high loads as shown on architectural drawings. If required by the flooring system manufacturer, install recommended blocking below bleachers in the extended position. Force reduction pads or components shall be installed in accordance with maple flooring manufacturer’s guidelines. Provide 2” expansion voids at the perimeter and at all vertical obstructions.
  3. Adhesive should be used between the layers of plywood/ subfloor as recommended by the flooring system manufacturer.  The second layer of subfloor material shall be laid diagonally (45 degrees) (option: Install both layers of plywood at 45 degree angles to finished flooring.) over the first layer with 1/4” spacing all edges and breaking joints 4’. Attach second layer of subfloor material with recommended fasteners as specified by maple floor manufacturer.  Provide 2” expansion voids at the perimeter and at all vertical obstructions.
  4. Install maple parquet flooring into freshly applied adhesive in a continuous end-to-end or a parquet pattern.  
    1. OPTION: Install maple strip flooring per manufacturers’ recommend installation method.
  5. Provide appropriate expansion spacing without the use of a transfer plate providing an even and smooth transfer between the two surfaces or utilize a transfer plate between the two surfaces.  Consult your MFMA manufacturer for their recommended expansion spacing.


  1. Machine sand with coarse, medium and fine paper to a smooth, even and uniform surface.
  2. Remove sanding dust from entire surface by tack or vacuum.


  1. Inspect entire area of floor to insure that surface is acceptable for finishing, completely free from sanding dust.
  2. Apply seal and finish per finish manufacturer's instructions.
  3. Paint game lines as shown on drawings, between seal and first coat of finish. Game line paint shall be compatible with finish.


  1. Install synthetic flooring system on contiguous subfloor as noted above and as specified by maple flooring manufacturer in all locations outside/ around the maple flooring or as shown on drawings. Synthetic flooring shall be the same finish floor height as the maple flooring. Synthetic flooring shall be installed in such a manner there is no need for a transition threshold between the maple and synthetic surfaces.
  2. Any unique construction adjustments to subflooring components under synthetic flooring portions of the system shall be done in accordance with manufacturer’s recommendations.
  3. After synthetic flooring has been installed / cured, apply gamelines, graphics, boarders, etc in accordance with drawings and manufacturer’s recommendations.
  4. Provide appropriate expansion spacing without the use of a transfer plate providing and even and smooth transfer between the two surfaces or utilize a transfer plate between the two surfaces.  Consult your MFMA manufacturer for their recommended expansion spacing.
  5. After the gamelines are completed the area must be kept free of foot traffic for a minimum of 7 days.


  1. Install vented cove base as per manufacturer’s instructions.
  2. Miter inside corners and use pro-molded outside corners.

Disclaimer: The MFMA provides general information to architects, specifiers and consumers. The MFMA, its members, officers and agents disclaim any responsibility whatsoever for the accuracy or applicability of these guidelines under all circumstances and conditions.

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