CFI Surface Preparation & Safety Procedures 2 — Questions and Answers
Question 1: When using a floor grinder to prepare a concrete subfloor, which PPE is most critical to prevent long-term health damage?
- Safety glasses
- N95 respirator or higher (Correct answer)
- Leather gloves
- Steel-toed boots
Correct answer: N95 respirator or higher
Concrete dust contains silica, which causes silicosis; an N95 or P100 respirator is essential when grinding.
Question 2: A moisture vapor emission rate (MVER) test on a concrete slab reads 8 lbs/1000 sq ft/24 hrs. What is the appropriate next step before installing adhesive-set flooring?
- Proceed immediately — 8 lbs is acceptable
- Apply a moisture mitigation system (Correct answer)
- Grind the surface and retest
- Install a polyethylene sheet underlayment
Correct answer: Apply a moisture mitigation system
Most adhesive manufacturers require MVER ≤ 3–5 lbs; 8 lbs exceeds limits and requires a moisture mitigation coating.
Question 3: Which tool is used to check that a concrete subfloor meets the flatness requirement of 3/16" over a 10-foot span?
- Tape measure
- 10-foot straightedge (Correct answer)
- Carpenter's square
- Laser level only
Correct answer: 10-foot straightedge
A 10-foot straightedge is the standard tool to verify the 3/16" flatness tolerance across a concrete slab.
Question 4: What is the primary hazard of using a propane-powered buffer in an enclosed space without ventilation?
- Excessive vibration damaging the subfloor
- Carbon monoxide poisoning (Correct answer)
- Electrostatic discharge igniting adhesive
- Noise-induced hearing loss
Correct answer: Carbon monoxide poisoning
Propane combustion produces carbon monoxide, which is odorless and deadly in poorly ventilated spaces.
Question 5: Before shot-blasting a concrete subfloor, the installer should first:
- Apply a bonding primer
- Remove all loose debris and oil contamination (Correct answer)
- Wet the surface to control dust
- Install perimeter tack strips
Correct answer: Remove all loose debris and oil contamination
Oil contamination must be removed before shot-blasting because it can embed into the surface and interfere with adhesion.
Question 6: An installer notices a previous flooring contained asbestos-containing materials (ACM). What is the correct action?
- Grind it smooth and install over it
- Cover with self-leveler and proceed
- Stop work and contact a licensed asbestos abatement contractor (Correct answer)
- Encapsulate with primer and continue
Correct answer: Stop work and contact a licensed asbestos abatement contractor
Disturbing ACM without proper abatement violates EPA and OSHA regulations; only licensed contractors may remove it.
Question 7: What does a pH reading above 9 on a concrete subfloor indicate before installing resilient flooring?
- The slab is too acidic for adhesive
- Elevated alkalinity that may attack adhesive bonds (Correct answer)
- The slab is fully cured and ready
- Moisture is within acceptable limits
Correct answer: Elevated alkalinity that may attack adhesive bonds
High alkalinity (pH > 9) can break down adhesive chemistry and cause flooring failures; mitigation is required.
CFI Surface Preparation & Safety Procedures 2
When using a floor grinder to prepare a concrete subfloor, which PPE is most critical to prevent long-term health damage?