RRT Subfloor Preparation & Assessment 2

Question 1

Which in-situ test method measures relative humidity within a concrete slab using probes inserted at 40% of slab depth?

Accepted Answer

ASTM F2170 relative humidity test

Answer

ASTM F2170 uses in-situ relative humidity probes placed at 40% slab depth to measure internal moisture conditions in concrete.

Question 2

What minimum thickness of plywood is typically required as an underlayment panel over a board subfloor before carpet installation?

Accepted Answer

3/8 inch

Answer

A minimum 3/8-inch plywood underlayment is generally required over skip-sheathing or board subfloors to provide a smooth, stable base for carpet.

Question 3

When testing a subfloor for squeaks, the technician should check fastener spacing. What is the typical maximum fastener spacing for subfloor panels per code?

Accepted Answer

6 inches on edges, 12 inches in the field

Answer

Standard code requires subfloor panel fasteners at 6-inch intervals along edges and 12-inch intervals in the field to prevent movement and squeaks.

Question 4

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?

Accepted Answer

Self-leveling underlayment compound

Answer

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.

Question 5

What is the primary purpose of the ASTM D4263 plastic sheet test for subfloors?

Accepted Answer

To detect the presence of moisture in or below the subfloor

Answer

The ASTM D4263 plastic sheet test is a qualitative method for detecting moisture beneath or within a concrete slab using a taped plastic sheet.

RRT - Carpet Repair and Reinstallation Technician Practice Test

RRT - Carpet Repair and Reinstallation Technician Practice Test

RRT Subfloor Preparation & Assessment 2