Page 1 of 113
Certified Tile Installer (CTI) Exam QUESTIONS AND
VERIFIED ANSWERS WITH RATIONALES JUST
RELEASED
Certified Tile Installer (CTI) Exam topics, The questions are based on the TCNA Handbook for Ceramic,
Glass, and Stone Tile Installation, ANSI A108/A118/A136.1 standards, ASTM C373, and CTEF Field
Manual.
SUMMARIZED EXAM TOPIC COVERAGE (Point Form)
Tile & Material Standards
• ANSI A137.1 – Tile dimensional tolerances, water absorption (impervious ≤0.5%, vitreous 0.5–
3%, semi-vitreous 3–7%, non-vitreous >7%), PEI wear ratings, DCOF slip resistance
• ASTM C373 – Water absorption testing
• Tile types: porcelain (through-body, glazed), ceramic, quarry, mosaic, natural stone
(marble/calcite, slate, quartzite, granite, travertine, limestone, terracotta)
• Large-format tile (≥15" any side) – special handling, lippage, minimum 80% coverage
Substrate Preparation
• Concrete: minimum 28-day cure (ASTM F2170 RH ≤75% for cementitious, ≤85% for epoxy)
• Wood: double-layer plywood (min 5/8" each), deflection L/360 for ceramic, L/720 for natural
stone
• Gypsum underlayment: requires acrylic primer
• Mud beds: exterior minimum 1-1/4" thickness with reinforcement
• Flatness: 1/8" in 10 ft for large-format tile; 1/4" in 10 ft for smaller
Underlayments & Membranes
• Cement backer board (CBU): 1/4" for floors, 1/2" for walls – proper fastener schedule
• Uncoupling membranes (e.g., Schluter-DITRA) – accommodate in-plane movement
• Crack isolation membranes – for concrete cracks ≤1/8"
• Waterproofing: liquid-applied (roll-on), sheet membranes, shower pan liners (pre-slope, 1/4"
per ft slope)
• Vapor retarder for showers/steam rooms
Setting Materials
• Thinset mortar: ANSI A118.4 (modified), A118.1 (unmodified), A118.11 (economy)
• Large-format tile requires medium-bed mortar to prevent sinkage
• Epoxy mortar (A118.3) – chemical resistance, steam rooms, commercial kitchens
• Mastic (A136.1) – limited to dry interior walls only
Grout
• Cementitious grout (ANSI A118.6, A118.7)
• Epoxy grout (A118.3) – stain-proof, chemical-resistant, steam rooms, commercial
• Grout joint minimum: 1/16" for rectified tile; 1/8" typical for calibrated tile
• Unsanded (≤1/8" joint), sanded (≥1/8" joint), urethane
Movement & Expansion Joints
• TCNA EJ171 – perimeters, changes of plane, structural joints
• Soft joints (silicone sealant) – interior every 20–25 ft, exterior every 8–12 ft
• Perimeter gap: 1/4" minimum
Shower & Wet Area Construction
• Shower pan liner: slope to drain, curb height 2" above drain, flood test
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• Liquid waterproofing: minimum 2 coats, mil thickness
• Backer board seams: alkaline-resistant mesh tape + thinset
Cutting & Fabrication
• Wet saw: diamond blade, water cooling, straight cuts
• Angle grinder: radius cuts, notches (L-cut), inside corners
• Snap cutter: straight cuts only, scored and snapped
• Hole drilling: diamond core bits
Installation Workmanship
• 80% minimum coverage (interior dry), 95% for wet/shower
• Lippage standards: ANSI A108.02 – varies by tile size and offset
• Mortar coverage inspection: periodic tile removal
• Trowel notch selection: based on tile size (1/4"x1/4" for ≤6", 1/2"x1/2" for large-format)
Natural Stone
• Calcite-based (marble, limestone, travertine) – etch from acids, requires sealer
• Silica-based (granite, quartzite) – acid-resistant
• Slate – fissures, flaking risk, heavy grade only for floors
• Gauged porcelain panels (ANSI A108.19, A137.3) – suction cups, lippage tuning
Special Conditions
• Radiant heat: uncoupling membrane or approved system, expansion allowances
• Freeze-thaw: impervious tile (≤0.5% absorption) only for exterior
• Steam rooms: epoxy grout, waterproofing, vapor barrier, slope to drain
• Commercial kitchens/floors: epoxy terrazzo or full-body porcelain + epoxy grout
Industry Standards & Associations
• TCNA – Handbook (methods, EJ171)
• ANSI – A108, A118, A136.1, A137.1, A137.3
• ASTM – C373, C1028 (COF), F2170 (RH), C627 (Robinson floor test)
• NTCA – Reference manual, field guidelines
1. A tile sample submitted for testing shows water absorption of 0.3% per ASTM C373. How is this tile
classified under ANSI A137.1?
A) Non-vitreous
B) Semi-vitreous
C) Vitreous
D) Impervious
Answer: D – Impervious tile has ≤0.5% absorption; porcelain tile falls in this category.
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2. A homeowner requests saltillo tile in a covered but unheated entryway in a climate with winter
freeze-thaw cycles. What is your best recommendation?
A) Proceed with standard installation as saltillo is frost-proof
B) Reject the job for this location because high-absorption saltillo (≥10%) will spall in freeze-thaw
C) Seal tile with two coats of penetrating sealer and use epoxy grout
D) Install over uncoupling membrane with heated mat below
Answer: B – Terracotta/saltillo has high absorption (≥8–10%) and is not freeze-thaw resistant; spalling
will occur.
3. According to the CTI technical proficiency exam description, which two materials form the primary
study references for the written test?
A) NTCA Reference Manual and Marble Institute Stone Guide
B) TCNA Handbook for Ceramic, Glass, and Stone Tile Installation and CTEF Field Manual
C) ANSI A108 and OSHA construction safety standards
D) TCNA Handbook and Schluter Installation Handbook
Answer: B – CTEF specifies the TCNA Handbook and CTEF Field Manual as the primary study references.
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4. A commercial kitchen floor requires tile that resists lactic acid from dairy spills and heavy washdowns.
Which combination is most appropriate?
A) Glazed ceramic tile with cementitious grout
B) Unglazed full-body porcelain tile with epoxy grout
C) Quarry tile with sanded grout
D) Saltillo tile with penetrating sealer
Answer: B – Epoxy terrazzo or full-body porcelain with epoxy grout resists chemical attack and thermal
shock.
5. When installing large-format tile (24" x 48") on a floor, what minimum flatness is required per ANSI
A108.02?
A) 1/8 inch in 8 feet
B) 1/8 inch in 10 feet
C) 1/4 inch in 10 feet
D) 1/4 inch in 6 feet
Answer: B – ANSI A108.02 requires 1/8 inch in 10 feet for large-format tile; smaller tile allows 1/4 inch in
10 feet.
Certified Tile Installer (CTI) Exam QUESTIONS AND
VERIFIED ANSWERS WITH RATIONALES JUST
RELEASED
Certified Tile Installer (CTI) Exam topics, The questions are based on the TCNA Handbook for Ceramic,
Glass, and Stone Tile Installation, ANSI A108/A118/A136.1 standards, ASTM C373, and CTEF Field
Manual.
SUMMARIZED EXAM TOPIC COVERAGE (Point Form)
Tile & Material Standards
• ANSI A137.1 – Tile dimensional tolerances, water absorption (impervious ≤0.5%, vitreous 0.5–
3%, semi-vitreous 3–7%, non-vitreous >7%), PEI wear ratings, DCOF slip resistance
• ASTM C373 – Water absorption testing
• Tile types: porcelain (through-body, glazed), ceramic, quarry, mosaic, natural stone
(marble/calcite, slate, quartzite, granite, travertine, limestone, terracotta)
• Large-format tile (≥15" any side) – special handling, lippage, minimum 80% coverage
Substrate Preparation
• Concrete: minimum 28-day cure (ASTM F2170 RH ≤75% for cementitious, ≤85% for epoxy)
• Wood: double-layer plywood (min 5/8" each), deflection L/360 for ceramic, L/720 for natural
stone
• Gypsum underlayment: requires acrylic primer
• Mud beds: exterior minimum 1-1/4" thickness with reinforcement
• Flatness: 1/8" in 10 ft for large-format tile; 1/4" in 10 ft for smaller
Underlayments & Membranes
• Cement backer board (CBU): 1/4" for floors, 1/2" for walls – proper fastener schedule
• Uncoupling membranes (e.g., Schluter-DITRA) – accommodate in-plane movement
• Crack isolation membranes – for concrete cracks ≤1/8"
• Waterproofing: liquid-applied (roll-on), sheet membranes, shower pan liners (pre-slope, 1/4"
per ft slope)
• Vapor retarder for showers/steam rooms
Setting Materials
• Thinset mortar: ANSI A118.4 (modified), A118.1 (unmodified), A118.11 (economy)
• Large-format tile requires medium-bed mortar to prevent sinkage
• Epoxy mortar (A118.3) – chemical resistance, steam rooms, commercial kitchens
• Mastic (A136.1) – limited to dry interior walls only
Grout
• Cementitious grout (ANSI A118.6, A118.7)
• Epoxy grout (A118.3) – stain-proof, chemical-resistant, steam rooms, commercial
• Grout joint minimum: 1/16" for rectified tile; 1/8" typical for calibrated tile
• Unsanded (≤1/8" joint), sanded (≥1/8" joint), urethane
Movement & Expansion Joints
• TCNA EJ171 – perimeters, changes of plane, structural joints
• Soft joints (silicone sealant) – interior every 20–25 ft, exterior every 8–12 ft
• Perimeter gap: 1/4" minimum
Shower & Wet Area Construction
• Shower pan liner: slope to drain, curb height 2" above drain, flood test
, Page 2 of 113
• Liquid waterproofing: minimum 2 coats, mil thickness
• Backer board seams: alkaline-resistant mesh tape + thinset
Cutting & Fabrication
• Wet saw: diamond blade, water cooling, straight cuts
• Angle grinder: radius cuts, notches (L-cut), inside corners
• Snap cutter: straight cuts only, scored and snapped
• Hole drilling: diamond core bits
Installation Workmanship
• 80% minimum coverage (interior dry), 95% for wet/shower
• Lippage standards: ANSI A108.02 – varies by tile size and offset
• Mortar coverage inspection: periodic tile removal
• Trowel notch selection: based on tile size (1/4"x1/4" for ≤6", 1/2"x1/2" for large-format)
Natural Stone
• Calcite-based (marble, limestone, travertine) – etch from acids, requires sealer
• Silica-based (granite, quartzite) – acid-resistant
• Slate – fissures, flaking risk, heavy grade only for floors
• Gauged porcelain panels (ANSI A108.19, A137.3) – suction cups, lippage tuning
Special Conditions
• Radiant heat: uncoupling membrane or approved system, expansion allowances
• Freeze-thaw: impervious tile (≤0.5% absorption) only for exterior
• Steam rooms: epoxy grout, waterproofing, vapor barrier, slope to drain
• Commercial kitchens/floors: epoxy terrazzo or full-body porcelain + epoxy grout
Industry Standards & Associations
• TCNA – Handbook (methods, EJ171)
• ANSI – A108, A118, A136.1, A137.1, A137.3
• ASTM – C373, C1028 (COF), F2170 (RH), C627 (Robinson floor test)
• NTCA – Reference manual, field guidelines
1. A tile sample submitted for testing shows water absorption of 0.3% per ASTM C373. How is this tile
classified under ANSI A137.1?
A) Non-vitreous
B) Semi-vitreous
C) Vitreous
D) Impervious
Answer: D – Impervious tile has ≤0.5% absorption; porcelain tile falls in this category.
, Page 3 of 113
2. A homeowner requests saltillo tile in a covered but unheated entryway in a climate with winter
freeze-thaw cycles. What is your best recommendation?
A) Proceed with standard installation as saltillo is frost-proof
B) Reject the job for this location because high-absorption saltillo (≥10%) will spall in freeze-thaw
C) Seal tile with two coats of penetrating sealer and use epoxy grout
D) Install over uncoupling membrane with heated mat below
Answer: B – Terracotta/saltillo has high absorption (≥8–10%) and is not freeze-thaw resistant; spalling
will occur.
3. According to the CTI technical proficiency exam description, which two materials form the primary
study references for the written test?
A) NTCA Reference Manual and Marble Institute Stone Guide
B) TCNA Handbook for Ceramic, Glass, and Stone Tile Installation and CTEF Field Manual
C) ANSI A108 and OSHA construction safety standards
D) TCNA Handbook and Schluter Installation Handbook
Answer: B – CTEF specifies the TCNA Handbook and CTEF Field Manual as the primary study references.
, Page 4 of 113
4. A commercial kitchen floor requires tile that resists lactic acid from dairy spills and heavy washdowns.
Which combination is most appropriate?
A) Glazed ceramic tile with cementitious grout
B) Unglazed full-body porcelain tile with epoxy grout
C) Quarry tile with sanded grout
D) Saltillo tile with penetrating sealer
Answer: B – Epoxy terrazzo or full-body porcelain with epoxy grout resists chemical attack and thermal
shock.
5. When installing large-format tile (24" x 48") on a floor, what minimum flatness is required per ANSI
A108.02?
A) 1/8 inch in 8 feet
B) 1/8 inch in 10 feet
C) 1/4 inch in 10 feet
D) 1/4 inch in 6 feet
Answer: B – ANSI A108.02 requires 1/8 inch in 10 feet for large-format tile; smaller tile allows 1/4 inch in
10 feet.
