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Double Plywood Floor System

This Guide Specification is designed to assist in the production of actual architectural specifications for maple athletic flooring installations.

It is hoped that this guide will be of particular value to those who do not have a detailed knowledge of the construction of athletic floors and that it will aid in maintaining high construction standards. The information contained herein is based on best industry practices however the Maple Flooring Manufacturers Association, Inc. (MFMA), its members and employees, do not warrant the information contained herein as proper under all conditions. The MFMA reserves the right to revise these guide specifications as necessary.

With questions concerning information contained in this guide, please EMAIL MFMA or call us at 888-480-9138. Always refer to MFMA’s current list of POSITION STATEMENTS when writing any specification.



  1. This document specifies a wood strip or parquet gymnasium floor system consisting, in general, of maple flooring, wood subflooring, vapor retarder, sanding, sealers, finishes, game lines and wall base.
  2. The general contractor shall provide a concrete slab, troweled smooth and level to a tolerance of +/- 1/8" in a 10' radius, subject to the approval of the MFMA Mill Accredited Installation Company*.

    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. Subject to local conditions.
    3. Sand-Poly-Sand slab construction is not acceptable.
    4. Concrete shall be free of washed river gravel, pea gravel, flint or hardener additives.
  3.  The MFMA Mill Accredited Installation Company* shall provide all tools and services to install a complete wood floor system from the concrete’s surface vapor polyethylene retarder, when required, upward through the sanding and finishing, plus the installation of perimeter moldings.


  1. The wood flooring shall be MFMA-RL, MFMA-FJ or MFMA-PQ maple.
  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.


  1. Flooring shall be delivered to the premises and acclimated, if necessary.
  2. All pallets of flooring bundles should be opened and spread out to acclimate the flooring to environmental conditions in the building, when applicable.
  3. The floor system shall not be delivered or installed until all masonry, plastering/dry walling, tile 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 weather tight.


  1. Permanent heat, light and ventilation shall be installed and operating before, during and after installation, controlling a temperature range of 55 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. 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.


2.01    MATERIAL

  1. Vapor Retarder
    1. 6-mil polyethylene    
  2. Subfloor
    1. Cushioning shall be supplied and installed per manufacturer’s instructions.
    2. 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.  
  3. Maple Flooring Manufacturers Association (MFMA) Wood Flooring
    1. Flooring shall be MFMA-RL Northern Hard Maple, MFMA-FJ Northern Hard Maple; 25/32" or 1/2" thick x 3-1/4", 2-1/2", 2-1/4" or 1-1/2" wide; First, Second and Better, Third and Better, Third or Utility Grade; T & G and EM; grade marked and stamped as produced by an MFMA member manufacturer or MFMA-PQ Northern Hard Maple; 5/16" to 7/16" thick panels; Second and Better or Third Grade; grade marked and stamped as produced by an MFMA member manufacturer. 
  4. Fasteners
    1. Flooring fasteners shall be barbed cleats or coated staples, unless otherwise specified by MFMA flooring manufacturer. 
  5. Finishing Materials
    1. 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.
  6. Game Lines
    1. Game line paint(s) shall be recommended by the finishing materials manufacturer, and must be compatible with the finish.
  7. Perimeter
    1. Wall base shall be 4" x 3" x 4' heavy duty molded, vented, rubber or vinyl cove base with pre molded outside corners as supplied by flooring manufacturer.


3.01    INSPECTION        

  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 with surface vapor retarder, lapping joints a minimum of 6" or as specified by the vapor retarder manufacturer.
  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. The underside of the first layer shall have 32 cushion pads per sheet attached 12" O.C. and 6" from edges of subfloor material on all sides. Provide 2" expansion voids at the perimeter and at all vertical obstructions.
  3. The second layer of subfloor material shall be laid diagonally (45 degrees) over the first layer 1/4" spacing all edges and breaking joints 4'. (Option: Install both layers of plywood at 45 degree angles to finished flooring.) Attach second layer of subfloor material with nails or staples 12" O.C. (When using parquet, construction adhesive should also be used between the layers of plywood as recommended by the flooring system manufacturer.) Provide 2" expansion voids at the perimeter and at all vertical obstructions.
  4. Install maple flooring parallel with main playing court by nailing or stapling approximately 12" O.C. or as specified by the flooring manufacturer.
    1. Space joints between flooring strips to allow for intermediate expansion in accordance with local humidity conditions.
    2. Provide 2" expansion voids at the perimeter and at all vertical obstructions.


  1. Sanding
    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.
  2. Finishing
    1. Inspect entire area of floor to ensure 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.

3.04    WALL BASE INSTALLATION           

  1. Install vented cove base by anchoring to walls with base cement, screws or anchors. 
  2. Miter inside corners, and use pre molded outside corners.


  1. Upon completion of floor installation, the owners, attendants or individuals in charge are responsible for the upkeep of the building and are to see that the care and maintenance instructions of the MFMA and the flooring manufacturer are followed.            

Notes: (*) Effective March 20, 2012                         

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