Hardwood Floors December 2025/January 2026

AT THE SITE

Why Flat Matters (Continued)

A subfloor that is not flat can create insurmountable problems for a contractor doing a decorative floor due to the inherent runoff and the gain. When doing ornamental floors, a flat subfloor is critical, as once a herringbone or chevron pattern starts to run off due to the subfloor, you are in a real world of hurt. This is obviously true of other patterned floors, border work, inlays, etc., all of which require a very flat subfloor. Another type of wood floor that requires a very flat subfloor is sports floors. The spec for them is 1/8” in 10’. Undulations in a sports floor can cause injury to participants, while undulations in an ornamental floor can cause you mental injury, not to mention financial.

PHOTOS COURTESY OF NWFA

The remedy is to evaluate any subfloor for flatness using a straight edge and carefully marking the highs and lows. When working with a concrete subfloor, you grind off the high areas and fill the low ones. Using a quality self-leveling Portland-based product works best. Small dips, holes, or cracks can be trowel-filled. The National Wood Flooring Association (NWFA), along with many manufacturers, offers training on the proper use of self-leveling underlayment. The bottom line is that if you want to elevate your business and offer ornamental floors, first pay close attention to the

subfloor flatness, and then choose a manufacturer you trust to provide quality products. Although it may cost a bit more, it ultimately will save you time, money, and reputation in the long run. If you are bidding on a decorative floor, don’t let yourself be beaten down on price for your labor or materials. Doing this type of work requires more time and attention to detail, as well as better milling. Trust me, if you screw it up, it will follow you for years to come. Remember, sometimes the floor you didn’t do is the best floor you never did! Bob Goldstein handles technical training and sales for Vermont Natural Coatings. He is an NWFA Certified Wood Flooring Inspector, Certified Installation Professional, and Certified Sand and Finish Professional. He can be reached at bobgoldstein46@yahoo.com.

For additional information about subfloors, check out the NWFA's Installation Guidelines at NWFA.ORG/TECHNICAL- GUIDELINES/.

WOOD FLOORING INSTALLATION GUIDELINES

Revised © 2019

12/3/2019 1:39:28 PM

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