CFI Subfloor Assessment & Preparation 3

Question 1

Subfloor panels should be installed with a gap between panel edges. What is the recommended gap size?

Accepted Answer

1/8 inch

Answer

A 1/8-inch gap between panel edges allows for seasonal expansion and prevents panel buckling.

Question 2

Which subfloor defect is MOST likely to cause ridging or telegraphing through sheet vinyl flooring?

Accepted Answer

Exposed panel edges or fastener heads that are proud

Answer

Proud fasteners or panel edges create hard points that telegraph directly through thin resilient sheet goods.

Question 3

What is the correct fastener pattern when installing a second layer of plywood underlayment over an existing subfloor?

Accepted Answer

Fasten at 6 inches on center in the field and 4 inches at edges

Answer

Closer edge fastening (4") prevents edge movement and peaking, while 6" field fastening provides adequate substrate stiffness.

Question 4

Before installing flooring over a radiant heat subfloor system, what is the maximum substrate surface temperature allowed during installation?

Accepted Answer

85°F

Answer

Most manufacturers require the radiant heat system be operating and surface temperature not exceed 85°F during installation to prevent adhesive or material issues.

Question 5

A concrete slab has an alkalinity (pH) reading of 11. What is the significance for flooring installation?

Accepted Answer

High pH can break down adhesive bonds and require primer or mitigation

Answer

Concrete pH above 9 can chemically attack certain adhesives, making pH testing and appropriate primer selection critical.

(CFI) Certified Flooring Installer Practice Test

(CFI) Certified Flooring Installer Practice Test

CFI Subfloor Assessment & Preparation 3