Page 1 of 56
CERTIFIED TILE INSTALLER (CTI) 2026
CERTIFICATION EXAM COMPLETE (160)
CURRENT TESTING QUESTIONS AND
CORRECT ANSWERS WITH DETAILED
RATIONALES|GRADED A+.
CTI
Prepare for the Certified Tile Installer (CTI) Certification – Practice Exam
with questions covering tile installation methods, substrate preparation,
waterproofing, layout techniques, material selection, tool usage, and
industry standards. This study guide helps reinforce essential tile
installation knowledge and supports effective certification exam
preparation. Designed to improve technical skills and boost confidence in
professional tile setting and construction work. Suitable for tile installers,
construction workers, and skilled trade professionals.
MULTIPLE CHOICE.
Section 1: Substrate Preparation and Surface Conditions
(Questions 1–30)
1. What is the maximum allowable variation in a concrete substrate
over 10 feet for large-format tile (15 inches or larger on any side)?
A) 1/8 inch
B) 1/4 inch
C) 3/8 inch
D) 1/2 inch
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Answer: B. 1/4 inch
Explanation: ANSI A108.02 requires a floor to be flat within 1/8 inch
in 10 feet for tiles with edges shorter than 15 inches, and 1/4 inch in
10 feet for large-format tiles.
2. A concrete slab must be cured for a minimum of how many days
before tile installation?
A) 7 days
B) 14 days
C) 28 days
D) 90 days
Answer: C. 28 days
Explanation: Concrete continues to shrink and release moisture for
at least 28 days; premature tiling risks bond failure and cracking.
3. What is the maximum acceptable moisture vapor emission rate
(MVER) for a concrete slab before installing impervious tile with
portland cement mortar?
A) 3 lbs per 1000 sq ft per 24 hours
B) 5 lbs per 1000 sq ft per 24 hours
C) 8 lbs per 1000 sq ft per 24 hours
D) 10 lbs per 1000 sq ft per 24 hours
Answer: B. 5 lbs per 1000 sq ft per 24 hours
Explanation: ANSI A108.02 recommends MVER below 5 lbs; higher
levels require mitigation or epoxy moisture control systems.
4. Which of the following is the most reliable method for testing
concrete floor flatness for tile installation?
A) 4-foot level with feeler gauge
B) 10-foot straightedge with wedges or feeler gauge
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C) Laser level only
D) Visual inspection
Answer: B. 10-foot straightedge with wedges or feeler gauge
Explanation: TCNA and ANSI specify the straightedge method for
measuring floor flatness.
5. A gypsum underlayment must be covered with a primer or a
separating membrane before tiling because:
A) Gypsum is too soft
B) Gypsum can react with portland cement and cause bond failure
C) Gypsum is too porous
D) Gypsum emits volatile organic compounds
Answer: B. Gypsum can react with portland cement and cause
bond failure
Explanation: Calcium sulfate in gypsum reacts with portland
cement to form ettringite, which destroys bond.
6. Plywood underlayment for ceramic tile must be at minimum:
A) Exterior grade, exposure 1, with C-D plugged face
B) Interior grade only
C) OSB oriented strand board with no face grade
D) Particleboard
Answer: A. Exterior grade, exposure 1, with C-D plugged face
Explanation: Exterior grade resists delamination from moisture;
interior grades are not suitable.
7. What is the minimum thickness for exterior glue plywood
underlayment over joists at 16 inches on center for tile?
A) 1/4 inch
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B) 3/8 inch
C) 1/2 inch
D) 5/8 inch
Answer: D. 5/8 inch (some sources 3/4 inch)
Explanation: TCNA recommends minimum 5/8 inch; 3/4 inch
preferred to reduce deflection.
8. The required gap between plywood panels for expansion is:
A) No gap
B) 1/16 inch
C) 1/8 inch
D) 1/4 inch
Answer: C. 1/8 inch
Explanation: Allows for expansion; gaps should be filled with
flexible sealant or left open.
9. Which of the following is an acceptable method to test for the
presence of a bond breaker on a concrete substrate?
A) Water droplet test
B) Pull test with adhesive tape
C) Light scratch test
D) Hammer sound test
Answer: A. Water droplet test
Explanation: A water droplet that beads up and does not absorb
indicates a bond breaker (curing compound, sealer) that must be
removed.
10. A latex-modified thin-set mortar can be applied over what
maximum residual moisture content in a concrete slab (using
CERTIFIED TILE INSTALLER (CTI) 2026
CERTIFICATION EXAM COMPLETE (160)
CURRENT TESTING QUESTIONS AND
CORRECT ANSWERS WITH DETAILED
RATIONALES|GRADED A+.
CTI
Prepare for the Certified Tile Installer (CTI) Certification – Practice Exam
with questions covering tile installation methods, substrate preparation,
waterproofing, layout techniques, material selection, tool usage, and
industry standards. This study guide helps reinforce essential tile
installation knowledge and supports effective certification exam
preparation. Designed to improve technical skills and boost confidence in
professional tile setting and construction work. Suitable for tile installers,
construction workers, and skilled trade professionals.
MULTIPLE CHOICE.
Section 1: Substrate Preparation and Surface Conditions
(Questions 1–30)
1. What is the maximum allowable variation in a concrete substrate
over 10 feet for large-format tile (15 inches or larger on any side)?
A) 1/8 inch
B) 1/4 inch
C) 3/8 inch
D) 1/2 inch
, Page 2 of 56
Answer: B. 1/4 inch
Explanation: ANSI A108.02 requires a floor to be flat within 1/8 inch
in 10 feet for tiles with edges shorter than 15 inches, and 1/4 inch in
10 feet for large-format tiles.
2. A concrete slab must be cured for a minimum of how many days
before tile installation?
A) 7 days
B) 14 days
C) 28 days
D) 90 days
Answer: C. 28 days
Explanation: Concrete continues to shrink and release moisture for
at least 28 days; premature tiling risks bond failure and cracking.
3. What is the maximum acceptable moisture vapor emission rate
(MVER) for a concrete slab before installing impervious tile with
portland cement mortar?
A) 3 lbs per 1000 sq ft per 24 hours
B) 5 lbs per 1000 sq ft per 24 hours
C) 8 lbs per 1000 sq ft per 24 hours
D) 10 lbs per 1000 sq ft per 24 hours
Answer: B. 5 lbs per 1000 sq ft per 24 hours
Explanation: ANSI A108.02 recommends MVER below 5 lbs; higher
levels require mitigation or epoxy moisture control systems.
4. Which of the following is the most reliable method for testing
concrete floor flatness for tile installation?
A) 4-foot level with feeler gauge
B) 10-foot straightedge with wedges or feeler gauge
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C) Laser level only
D) Visual inspection
Answer: B. 10-foot straightedge with wedges or feeler gauge
Explanation: TCNA and ANSI specify the straightedge method for
measuring floor flatness.
5. A gypsum underlayment must be covered with a primer or a
separating membrane before tiling because:
A) Gypsum is too soft
B) Gypsum can react with portland cement and cause bond failure
C) Gypsum is too porous
D) Gypsum emits volatile organic compounds
Answer: B. Gypsum can react with portland cement and cause
bond failure
Explanation: Calcium sulfate in gypsum reacts with portland
cement to form ettringite, which destroys bond.
6. Plywood underlayment for ceramic tile must be at minimum:
A) Exterior grade, exposure 1, with C-D plugged face
B) Interior grade only
C) OSB oriented strand board with no face grade
D) Particleboard
Answer: A. Exterior grade, exposure 1, with C-D plugged face
Explanation: Exterior grade resists delamination from moisture;
interior grades are not suitable.
7. What is the minimum thickness for exterior glue plywood
underlayment over joists at 16 inches on center for tile?
A) 1/4 inch
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B) 3/8 inch
C) 1/2 inch
D) 5/8 inch
Answer: D. 5/8 inch (some sources 3/4 inch)
Explanation: TCNA recommends minimum 5/8 inch; 3/4 inch
preferred to reduce deflection.
8. The required gap between plywood panels for expansion is:
A) No gap
B) 1/16 inch
C) 1/8 inch
D) 1/4 inch
Answer: C. 1/8 inch
Explanation: Allows for expansion; gaps should be filled with
flexible sealant or left open.
9. Which of the following is an acceptable method to test for the
presence of a bond breaker on a concrete substrate?
A) Water droplet test
B) Pull test with adhesive tape
C) Light scratch test
D) Hammer sound test
Answer: A. Water droplet test
Explanation: A water droplet that beads up and does not absorb
indicates a bond breaker (curing compound, sealer) that must be
removed.
10. A latex-modified thin-set mortar can be applied over what
maximum residual moisture content in a concrete slab (using
