CFI Moisture Mitigation Systems 3 — Questions and Answers
Question 1: When using ASTM F2170 in-situ probes, where in the slab depth should the hole be drilled for slabs drying from one side only?
- 25% of slab depth
- 40% of slab depth (Correct answer)
- 60% of slab depth
- Top 1 inch only
Correct answer: 40% of slab depth
For slabs drying from one side only (typical in-service condition), ASTM F2170 requires the probe hole to be drilled to 40% of the slab depth.
Question 2: A flooring contractor finds a MVER of 12 lbs/1,000 sq ft/24 hrs. Which is the most appropriate next step?
- Proceed with installation using a pressure-sensitive adhesive
- Install a moisture mitigation system rated for the measured MVER (Correct answer)
- Wait 30 days and retest without any treatment
- Apply two coats of latex primer and proceed
Correct answer: Install a moisture mitigation system rated for the measured MVER
A MVER of 12 lbs exceeds the typical 3–5 lb threshold for most adhesives, requiring an approved moisture mitigation system rated to handle the actual measured level.
Question 3: What is the function of sand broadcast into a wet moisture mitigation coating?
- To reduce the cost of the coating system
- To add slip resistance for worker safety during installation
- To create a mechanical bond profile for the flooring adhesive or underlayment (Correct answer)
- To speed up the curing time of the epoxy
Correct answer: To create a mechanical bond profile for the flooring adhesive or underlayment
Broadcasting sand into the wet coating creates a textured surface profile that allows flooring adhesives or self-leveling underlayment to mechanically bond to the mitigation layer.
Question 4: Which type of flooring is MOST sensitive to moisture vapor and most likely to require mitigation even at moderate RH levels?
- Unglazed ceramic tile set in thick-bed mortar
- Solid hardwood flooring (Correct answer)
- Polished concrete with penetrating sealer
- Porcelain tile with epoxy grout
Correct answer: Solid hardwood flooring
Solid hardwood flooring is highly hygroscopic and will cup, warp, or buckle with exposure to elevated moisture vapor, making it extremely sensitive to subfloor moisture conditions.
Question 5: How long must an ASTM F1869 calcium chloride test kit typically remain sealed on the concrete before reading?
- 8 hours
- 24 hours
- 60–72 hours (Correct answer)
- 7 days
Correct answer: 60–72 hours
ASTM F1869 requires the calcium chloride dish to remain sealed under the dome for 60–72 hours before weighing to determine moisture vapor emission rate.
Question 6: What minimum number of calcium chloride tests does ASTM F1869 require for the first 1,000 sq ft of floor area?
- 1 test
- 3 tests (Correct answer)
- 5 tests
- 10 tests
Correct answer: 3 tests
ASTM F1869 requires a minimum of 3 tests for the first 1,000 sq ft, then 1 additional test for each additional 1,000 sq ft.
Question 7: What is the typical minimum curing time for a two-component epoxy moisture mitigation system before flooring installation can proceed?
- 1 hour
- 4 hours
- 12–24 hours (Correct answer)
- 72 hours
Correct answer: 12–24 hours
Most two-component epoxy moisture mitigation systems require 12–24 hours of curing time at standard conditions before flooring can be installed over them.
CFI Moisture Mitigation Systems 3
When using ASTM F2170 in-situ probes, where in the slab depth should the hole be drilled for slabs drying from one side only?