The Maple Flooring Manufacturers Association (MFMA) requires the general contractor to provide a concrete slab troweled smooth and flat to a tolerance of 1/8" in a 10' radius, subject to the approval of the MFMA Sport Floor Contractor.

Labor and materials necessary to put the concrete slab in acceptable condition, (high areas ground down and low areas filled with appropriate leveling compounds) are the responsibility of the general contractor or concrete subcontractor.

No pea gravel, river gravel or slag aggregate can be allowed in a gymnasium concrete slab. The concrete strength range at the time of wood flooring installation should be between 3,000 P.S.I. and 3,500 P.S.I.

MFMA recommends the following procedures to be used by the general contractor or concrete subcontractor to provide the appropriate slab flatness requirement:

  1. Plot a 5' grid on the slab surface.
  2. Using a 10' straight edge, move it perpendicular to the plotted grid in both directions to identify all areas requiring correction. (Note: The use of a transit or laser alone does not include measurements between the grid points.)
  3. All high spots should be ground level. Fill low areas with appropriate leveling compound. The fill must not become brittle, crack or lose bonding to the concrete slab. Fill must not be affected by loads applied to resilient pads if present. In anchored system applications, the fill must provide the required P.S.I. strength and allow anchoring without breaking or spawling when pins are installed. This is the responsibility of the general contractor or concrete subcontractor.

Note: Please request additional MFMA guidelines if Ff/Fl numbers have been specified.

If you have any additional questions, please contact MFMA’s Technical Director at 888-480-9138.


Revised 11/15
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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