PREPIQ ILLINOIS TILE & MARBLE CONTRACTOR
PRACTICE EXAM|QUESTIONS AND ANSWERS WITH
RATIONALE|GRADED A+|2026 UPDATE|100% CORRECT
Technical Installation (1–40)
What is the minimum slope required for a shower pan to drain properly?
A. 1/8" per foot
B. 1/4" per foot
C. 1/2" per foot
D. 1" per foot
Answer: B
Rationale: Code and ANSI standards require a minimum slope of ¼" per foot toward the drain to
prevent standing water.
Which trowel notch size is appropriate for a 12″×12″ porcelain tile on a floor?
A. 1/8″ V-notch
B. 1/4″ square notch
C. 1/2″ × 1/2″ square notch
D. 3/4″ U-notch
Answer: C
Rationale: Larger tiles require more mortar coverage; a ½″×½″ notch ensures proper adhesive
contact.
Before installing tile over a wood subfloor, the minimum recommended underlayment is:
A. 1/4″ plywood
B. 1/2″ cement backer board
C. 1/4″ cement backer board over 5/8″ plywood
D. 3/4″ OSB only
Answer: C
Rationale: ANSI standards call for cement backer board over a structurally adequate plywood
subfloor to prevent movement and cracking.
, Which grout type is recommended for a 1/8″ joint in a bathroom floor?
A. Sanded
B. Unsanded
C. Epoxy
D. Latex-modified
Answer: B
Rationale: Unsanded grout is used for narrow joints (<1/8") to avoid scratching the tile.
Which material is most resistant to moisture and mold for wet areas?
A. Plywood underlayment
B. Cement backer board
C. OSB
D. Vinyl underlayment
Answer: B
Rationale: Cementitious backer boards are water-resistant and ideal for showers, baths, and wet
areas.
For exterior porcelain tile, what is the recommended installation method?
A. Thinset only
B. Thinset over a membrane
C. Mortar bed with lath
D. Adhesive tape method
Answer: B
Rationale: A water-proofing membrane beneath the thinset prevents moisture infiltration in
exterior applications.
When laying natural stone tile, what is crucial to prevent lippage?
A. Using unsanded grout
B. Checking stone thickness and selecting proper trowel size
C. Applying epoxy adhesive
D. Using large joints only
Answer: B
Rationale: Stone varies in thickness; leveling is essential to ensure even surfaces and prevent
lippage.
What is the ANSI standard for mortar coverage under a floor tile?
A. 50%
B. 60%
C. 80%
, D. 100%
Answer: C
Rationale: ANSI A108 recommends at least 80% mortar coverage for floor tiles to prevent hollow
spots.
What is the correct sequence when installing a tile shower wall?
A. Waterproofing, layout, tile, grout
B. Tile, waterproofing, grout
C. Layout, tile, waterproofing, grout
D. Grout, tile, waterproofing
Answer: A
Rationale: Membrane is installed first, then layout, then tile, followed by grouting.
1 Which of the following best describes a ‘mud bed’ installation?
A. A thinset method over backer board
B. A thick mortar bed to level floor
C. Epoxy adhesive method
D. Direct glue down
Answer: B
Rationale: A mud bed provides a solid, level base for tile in traditional installations.
1 What is the purpose of using a decoupling membrane?
A. Increase slip resistance
B. Prevent cracks from transferring from subfloor
C. Make grout waterproof
D. Add aesthetic texture
Answer: B
Rationale: Decoupling membranes absorb movement between subfloor and tile to reduce
cracking.
1 Which adhesive is recommended for large format tiles (>15" on a side)?
A. Standard thinset
B. Modified thinset
C. Epoxy grout
D. Mastic
Answer: B
Rationale: Modified thinset with latex or polymer improves bond and prevents tile slippage.
1 Tile expansion joints are required:
A. Every 8–12 ft in interior floors
PRACTICE EXAM|QUESTIONS AND ANSWERS WITH
RATIONALE|GRADED A+|2026 UPDATE|100% CORRECT
Technical Installation (1–40)
What is the minimum slope required for a shower pan to drain properly?
A. 1/8" per foot
B. 1/4" per foot
C. 1/2" per foot
D. 1" per foot
Answer: B
Rationale: Code and ANSI standards require a minimum slope of ¼" per foot toward the drain to
prevent standing water.
Which trowel notch size is appropriate for a 12″×12″ porcelain tile on a floor?
A. 1/8″ V-notch
B. 1/4″ square notch
C. 1/2″ × 1/2″ square notch
D. 3/4″ U-notch
Answer: C
Rationale: Larger tiles require more mortar coverage; a ½″×½″ notch ensures proper adhesive
contact.
Before installing tile over a wood subfloor, the minimum recommended underlayment is:
A. 1/4″ plywood
B. 1/2″ cement backer board
C. 1/4″ cement backer board over 5/8″ plywood
D. 3/4″ OSB only
Answer: C
Rationale: ANSI standards call for cement backer board over a structurally adequate plywood
subfloor to prevent movement and cracking.
, Which grout type is recommended for a 1/8″ joint in a bathroom floor?
A. Sanded
B. Unsanded
C. Epoxy
D. Latex-modified
Answer: B
Rationale: Unsanded grout is used for narrow joints (<1/8") to avoid scratching the tile.
Which material is most resistant to moisture and mold for wet areas?
A. Plywood underlayment
B. Cement backer board
C. OSB
D. Vinyl underlayment
Answer: B
Rationale: Cementitious backer boards are water-resistant and ideal for showers, baths, and wet
areas.
For exterior porcelain tile, what is the recommended installation method?
A. Thinset only
B. Thinset over a membrane
C. Mortar bed with lath
D. Adhesive tape method
Answer: B
Rationale: A water-proofing membrane beneath the thinset prevents moisture infiltration in
exterior applications.
When laying natural stone tile, what is crucial to prevent lippage?
A. Using unsanded grout
B. Checking stone thickness and selecting proper trowel size
C. Applying epoxy adhesive
D. Using large joints only
Answer: B
Rationale: Stone varies in thickness; leveling is essential to ensure even surfaces and prevent
lippage.
What is the ANSI standard for mortar coverage under a floor tile?
A. 50%
B. 60%
C. 80%
, D. 100%
Answer: C
Rationale: ANSI A108 recommends at least 80% mortar coverage for floor tiles to prevent hollow
spots.
What is the correct sequence when installing a tile shower wall?
A. Waterproofing, layout, tile, grout
B. Tile, waterproofing, grout
C. Layout, tile, waterproofing, grout
D. Grout, tile, waterproofing
Answer: A
Rationale: Membrane is installed first, then layout, then tile, followed by grouting.
1 Which of the following best describes a ‘mud bed’ installation?
A. A thinset method over backer board
B. A thick mortar bed to level floor
C. Epoxy adhesive method
D. Direct glue down
Answer: B
Rationale: A mud bed provides a solid, level base for tile in traditional installations.
1 What is the purpose of using a decoupling membrane?
A. Increase slip resistance
B. Prevent cracks from transferring from subfloor
C. Make grout waterproof
D. Add aesthetic texture
Answer: B
Rationale: Decoupling membranes absorb movement between subfloor and tile to reduce
cracking.
1 Which adhesive is recommended for large format tiles (>15" on a side)?
A. Standard thinset
B. Modified thinset
C. Epoxy grout
D. Mastic
Answer: B
Rationale: Modified thinset with latex or polymer improves bond and prevents tile slippage.
1 Tile expansion joints are required:
A. Every 8–12 ft in interior floors
