CTI Surface Preparation & Adhesives 2 — Questions and Answers
Question 1: What is the maximum allowable moisture vapor emission rate (MVER) for a concrete slab before installing a moisture-sensitive adhesive?
- 3 lbs/1000 sq ft/24 hrs
- 5 lbs/1000 sq ft/24 hrs (Correct answer)
- 8 lbs/1000 sq ft/24 hrs
- 10 lbs/1000 sq ft/24 hrs
Correct answer: 5 lbs/1000 sq ft/24 hrs
ANSI A108.02 limits MVER to 5 lbs per 1,000 sq ft per 24 hours for moisture-sensitive adhesives.
Question 2: When installing cement board over wood subfloors, which fastener pattern is required by ANSI standards?
- 6 inches on edges, 12 inches in the field (Correct answer)
- 8 inches on edges, 12 inches in the field
- 4 inches on edges, 8 inches in the field
- 6 inches on edges, 8 inches in the field
Correct answer: 6 inches on edges, 12 inches in the field
ANSI A108.11 requires screws or nails 6 inches on center at edges and 12 inches in the field for cement board.
Question 3: A glass mat gypsum backer board is best suited for which application?
- Floor tile in wet areas
- Wall tile in wet areas (Correct answer)
- Exterior tile applications
- Steam room walls
Correct answer: Wall tile in wet areas
Glass mat gypsum backer boards are designed for wall tile in wet areas but are not recommended for steam rooms or submerged conditions.
Question 4: Which test method uses a hood and calcium chloride crystals to measure concrete slab moisture emission?
- Relative humidity probe test (ASTM F2170)
- Calcium chloride test (ASTM F1869) (Correct answer)
- Plastic sheet test (ASTM D4263)
- pH surface test
Correct answer: Calcium chloride test (ASTM F1869)
ASTM F1869 is the calcium chloride test that measures moisture vapor emission rate (MVER) from concrete slabs.
Question 5: Organic mastic adhesive (Type I) should NOT be used in which situation?
- Dry interior wall applications
- Countertop backsplashes
- Continuously wet areas like showers (Correct answer)
- Above-grade residential walls
Correct answer: Continuously wet areas like showers
Organic mastic adhesives are not waterproof and must never be used in continuously wet or submerged areas.
Question 6: What is the purpose of back-buttering large-format tiles before setting?
- To add color to the adhesive
- To increase mortar coverage to the required minimum (Correct answer)
- To speed up the curing process
- To reduce the open time of the mortar
Correct answer: To increase mortar coverage to the required minimum
Back-buttering ensures full mortar coverage (minimum 80% dry/95% wet areas) on large tiles that may bridge mortar ridges.
Question 7: Which ANSI standard governs the installation requirements for ceramic tile using the thin-set method?
- ANSI A118.4
- ANSI A108.5 (Correct answer)
- ANSI A137.1
- ANSI A118.1
Correct answer: ANSI A108.5
ANSI A108.5 covers the installation of ceramic tile with dry-set portland cement mortar or latex-portland cement mortar.
CTI Surface Preparation & Adhesives 2
What is the maximum allowable moisture vapor emission rate (MVER) for a concrete slab before installing a moisture-sensitive adhesive?