Installation & Prep

3/16 inch over 10 feet is a flatness tolerance. It means that if a 10-foot straightedge is laid across the subfloor, no gap under it should exceed 3/16 inch at any point. It shows up in warranty language because most flooring problems attributed to a bad product are actually the floor underneath moving more than … Read more

Lay a rigid ten-foot straightedge on the floor, slide a set of feeler gauges or a tape measure under it at several points, and record the largest gap. Move the straightedge to a new spot and a new direction and repeat. The largest gap found anywhere is the floor’s flatness number, and it decides what … Read more