Subfloor Preparation & Assessment Flashcards
7 cards from real RRT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Subfloor Preparation & Assessment flashcards as text
Which in-situ test method measures relative humidity within a concrete slab using probes inserted at 40% of slab depth?
Answer: ASTM F2170 relative humidity test
ASTM F2170 uses in-situ relative humidity probes placed at 40% slab depth to measure internal moisture conditions in concrete.
What minimum thickness of plywood is typically required as an underlayment panel over a board subfloor before carpet installation?
Answer: 3/8 inch
A minimum 3/8-inch plywood underlayment is generally required over skip-sheathing or board subfloors to provide a smooth, stable base for carpet.
When testing a subfloor for squeaks, the technician should check fastener spacing. What is the typical maximum fastener spacing for subfloor panels per code?
Answer: 6 inches on edges, 12 inches in the field
Standard code requires subfloor panel fasteners at 6-inch intervals along edges and 12-inch intervals in the field to prevent movement and squeaks.
A technician discovers a low spot of 3/8 inch over a 3-foot span on a concrete subfloor. What is the appropriate repair material?
Answer: Self-leveling underlayment compound
Self-leveling underlayment compound is the correct choice for filling low spots on concrete subfloors as it flows to a flat finish and bonds to concrete.
What is the primary purpose of the ASTM D4263 plastic sheet test for subfloors?
Answer: To detect the presence of moisture in or below the subfloor
The ASTM D4263 plastic sheet test is a qualitative method for detecting moisture beneath or within a concrete slab using a taped plastic sheet.
When encountering an existing cutback adhesive residue on a concrete subfloor, the recommended approach for carpet reinstallation is to:
Answer: Skim coat over the residue with an appropriate embossing leveler
Encapsulating cutback adhesive residue with a compatible skim coat or embossing leveler is the recommended method, as grinding may release asbestos fibers in older adhesives.
Which condition in a crawl space most directly contributes to subfloor moisture problems above?
Answer: Inadequate ventilation and exposed ground soil
Inadequate ventilation combined with exposed soil allows ground moisture to evaporate upward into the crawl space and penetrate the subfloor.