Subfloor Preparation & Assessment Flashcards
6 cards from real CFI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Subfloor Preparation & Assessment flashcards as text
What is the maximum allowable floor flatness tolerance for most resilient flooring installations over a wood subfloor?
Answer: 3/16 inch in 10 feet
Most resilient flooring manufacturers specify a flatness tolerance of no more than 3/16 inch variation over a 10-foot span.
What minimum thickness of plywood subfloor is typically required beneath hardwood strip flooring?
Answer: 3/4 inch
A 3/4-inch plywood subfloor provides the structural rigidity needed to prevent squeaks and movement under hardwood strip flooring.
Which tool is used to detect high spots and low spots when assessing subfloor flatness?
Answer: Straightedge or flat bar
A long straightedge or flat bar is used to bridge the surface and identify deviations from flatness by revealing gaps beneath it.
What must be done to a concrete subfloor before installing glue-down LVP if the surface has a release agent residue?
Answer: Mechanically grind or scarify the surface
Release agents prevent adhesive bonding, so the concrete must be mechanically ground or scarified to expose a clean, porous surface.
What is the primary purpose of a self-leveling underlayment (SLU) on a concrete subfloor?
Answer: To fill low spots and achieve the required flatness tolerance
SLU is poured and flows to fill depressions, bringing the subfloor surface to the required flatness specification for flooring installation.
Before installing flooring over a radiant heat subfloor, what must the installer verify first?
Answer: That the system has been run through a heating cycle and the surface temperature is within acceptable limits
The radiant heat system should be cycled before installation so moisture is driven out of the concrete and the slab reaches a stable temperature.