Do You Have A “Dead Spot” On Your Gym Floor?

dead spot

In layman’s terms, “dead spots” are locations on a sports floor where ball rebound is markedly less than on the majority of the rest of the surface. Many flooring systems exhibit vibrations and sound variations when a basketball is bounced at different locations. Often, areas where vibrations and sound variations are observed are mistakenly termed “dead spots.” Provided the ball rebounds to a reasonably consistent height in comparison to other locations on the floor, areas where vibrations and sound variations are present do not typically qualify as true “dead spots.”

Concerns about “dead spots” are most often expressed with floating subfloor configurations. Floating floors often exhibit sound and vibration variations due to the structure of the subfloor components. Ball rebound can be affected on all subfloor configurations due to seasonal changes in flooring moisture contents and resulting system expansion/contraction. It is not uncommon for a true “dead spot” to move or disappear as a flooring system adjusts to varying seasonal moisture conditions — regardless of the subfloor system installed in the facility.

How do you confirm the presence of a true “dead spot” on your floor? MFMA uses PUR Standards for measuring ball rebound. PUR Standards use a concrete floor as a base measurement for rebound performance, and compares rebound on all engineered surfaces as a percentage relative to results on concrete. Specialized equipment is used to time impact intervals of a ball dropped at multiple locations across an athletic surface, and calculations based on these impact figures result in a composite score for the floor. Variations from the composite figure are examined to determine the presence of any true “dead spots.”

On a permanent PUR Compliant basketball floor, the ball’s rebound must maintain a 93 percent minimum average while a portable PUR Compliant basketball floor must maintain a 95 percent minimum average. The uniformity requirement of the MFMA PUR Standards is what makes it the North American standard for sports floors. MFMA recognizes the importance of a sports surface’s uniformity and consistent game play for a high quality floor. Permanent and portable PUR Compliant basketball floors must be within +/- 3 percent of the minimum average.

It is also important to remember that maple sports flooring systems typically settle into their environments over time, including repair areas. Assuming proper and consistent environmental conditions are maintained over the long-term, the greatest dimensional changes in most sports flooring systems occurs during the first 12- 24 months of the floor’s life span. As the floor ages, expansion and contraction cycles become much less pronounced provided environmental conditions remain consistent from year to year. Significant swings in indoor relative humidity must be avoided and the temperature and humidity levels must be maintained within specified ranges year-round to minimize movement.

For more information on recommended environmental conditions, PUR Standards or our third-party inspection services, please visit


Daniel Heney is the Executive Director at Maple Flooring Manufactures Association. He can be reached at 888.480.9138 or 

Dan Heney is the Executive Director of the Maple Flooring Manufacturers Association. He can be contacted at 888-480-9138 or by email at


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