CFI Surface Preparation & Safety Procedures 4 — Questions and Answers
Question 1: When installing flooring over radiant heat, the maximum recommended subfloor surface temperature at time of installation is:
- 85°F (29°C) (Correct answer)
- 95°F (35°C)
- 65°F (18°C)
- 75°F (24°C)
Correct answer: 85°F (29°C)
Most manufacturers specify that radiant-heated subfloor temperatures must not exceed 85°F during installation to avoid premature adhesive set.
Question 2: A floor self-leveling compound is specified at a maximum pour depth of 1 inch per lift. What should the installer do if a depression is 2 inches deep?
- Pour all 2 inches at once and allow extra cure time
- Apply in two separate lifts, allowing the first to cure per manufacturer specs (Correct answer)
- Fill with hydraulic cement only
- Grind down to reduce depth before leveling
Correct answer: Apply in two separate lifts, allowing the first to cure per manufacturer specs
Exceeding the maximum pour depth causes shrinkage cracking; applying in multiple lifts as recommended ensures proper cure.
Question 3: Before applying a skim coat of embossing leveler over existing resilient flooring, the installer should verify:
- The existing floor is waxed for adhesion
- The existing floor is structurally sound and fully bonded (Correct answer)
- The adhesive has cured for less than 24 hours
- The grout lines are filled with silicone caulk
Correct answer: The existing floor is structurally sound and fully bonded
Embossing leveler requires a stable, fully adhered substrate; any loose sections will telegraph through the new flooring.
Question 4: Which OSHA standard specifically governs the permissible exposure limit (PEL) for respirable crystalline silica in construction?
- 29 CFR 1910.1000
- 29 CFR 1926.1153 (Correct answer)
- 29 CFR 1926.62
- 29 CFR 1910.134
Correct answer: 29 CFR 1926.1153
29 CFR 1926.1153 is OSHA's silica standard for construction, setting a PEL of 50 µg/m³ as an 8-hour TWA.
Question 5: When scarifying a concrete subfloor to remove a thick adhesive residue, the installer should use:
- A single-disc floor buffer with a black pad
- A drum sander with 36-grit paper
- A mechanical scarifier or shot blaster (Correct answer)
- A hand scraper for all areas
Correct answer: A mechanical scarifier or shot blaster
Mechanical scarifiers and shot blasters efficiently remove thick adhesive residue and profile the concrete surface for re-bonding.
Question 6: What is the correct disposal method for empty containers of solvent-based flooring adhesive on a job site?
- Dispose in regular construction debris dumpster
- Rinse and recycle through standard curbside pickup
- Follow local hazardous waste regulations for disposal (Correct answer)
- Leave sealed on site for reuse
Correct answer: Follow local hazardous waste regulations for disposal
Empty solvent-based adhesive containers are classified as hazardous waste and must be disposed of per local and EPA regulations.
Question 7: An installer finds that a wood subfloor has a moisture content of 14% in a region where the flooring MC is 7%. What is the best course of action?
- Install immediately and use a moisture barrier underlayment
- Allow the subfloor to dry and retest before installation (Correct answer)
- Apply penetrating sealer and proceed
- Reduce the room temperature to equilibrate faster
Correct answer: Allow the subfloor to dry and retest before installation
A 7% MC differential far exceeds the typical 4% maximum allowed; the subfloor must dry to an acceptable range before installation.
CFI Surface Preparation & Safety Procedures 4
When installing flooring over radiant heat, the maximum recommended subfloor surface temperature at time of installation is: