Subfloor preparation requirements vary by product: wood flooring needs the subfloor flat within 3/16″ over 10 ft and moisture content below 12% (or within 4% of the flooring MC). Large-format tile requires flatness within 1/8″ over 10 ft with no deflection. LVP requires 3/16″ over 10 ft with all high spots and low spots corrected. RainFire Builders performs a full subfloor assessment — flatness measurement, moisture testing, and structural evaluation — before any flooring installation begins and documents findings before work proceeds.