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 F1869 calcium chloride test

Answer

ASTM D4263 plastic sheet test

Answer

ASTM C1583 tensile adhesion test

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

1/4 inch

Answer

1/2 inch

Answer

5/8 inch

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

8 inches on edges, 16 inches in the field

Answer

12 inches on edges, 24 inches in the field

Answer

4 inches on edges, 8 inches in the field

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

Portland cement mortar

Answer

Floor patching caulk

Answer

Gypsum-based joint compound

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

To measure the pH level of concrete

Answer

To determine the compressive strength of the slab

Answer

To test adhesive bond strength

Question 6

When encountering an existing cutback adhesive residue on a concrete subfloor, the recommended approach for carpet reinstallation is to:

Accepted Answer

Skim coat over the residue with an appropriate embossing leveler

Answer

Remove all residue by mechanical grinding before proceeding

Answer

Apply solvent to dissolve the residue completely

Answer

Install carpet directly over the residue without treatment

Question 7

Which condition in a crawl space most directly contributes to subfloor moisture problems above?

Accepted Answer

Inadequate ventilation and exposed ground soil

Answer

Too many floor joists

Answer

Low ceiling height in the crawl space

Answer

Absence of insulation between joists