Practice Examination Questions And

Certified Ceramic Tile Installer (CTI) Practice Examination Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

American National Tile Contractors Association (NTCA) & Ceramic Tile Education Foundation (CTEF)

• What is the minimum recommended grout joint width for tiles with

facial dimensions greater than 15 inches?

• 1/16 inch
• 1/8 inch
• 3/16 inch
• 1/4 inch

Rationale: Larger tiles require wider joints to compensate for

potential warpage and dimensional variation. 1 / 4

• What is the main purpose of a crack isolation membrane?

a) To reduce moisture transmission

b) To prevent substrate cracks from transferring to the tile surface

c) To increase tile bond strength

d) To act as a waterproof barrier

Rationale: Crack isolation membranes are designed to absorb

movement and prevent existing substrate cracks from telegraphing through tiles.

• Which mortar type is best suited for setting large-format porcelain

tiles on concrete?

a) Mastic

b) Dry-set mortar

c) Modified thinset mortar

d) Epoxy mortar

Rationale: Modified thinset mortar provides better adhesion and

flexibility for large-format tiles.

• Which ANSI standard applies to thin-set mortars for ceramic tile

installation?

a) ANSI A118.3

b) ANSI A108.5

c) ANSI A118.1 and A118.4

d) ANSI A118.10 2 / 4

Rationale: ANSI A118.1 covers unmodified thin-set mortars and

A118.4 covers modified thin-set mortars.

• What is the recommended minimum slope for a shower floor to the

drain?

• 1/8 inch per foot
• 1/4 inch per foot
• 3/8 inch per foot
• 1/2 inch per foot

Rationale: A 1/4-inch per foot slope ensures proper drainage without

water pooling.

• When cutting ceramic tile, which tool is best for achieving precise

curved cuts?

a) Tile snap cutter

b) Wet saw

c) Tile nipper

d) Scoring wheel

Rationale: Tile nippers are ideal for small curved or irregular cuts

that cannot be made with a straight saw.

• What is the primary function of grout in a tile installation?

a) To bond tile to the substrate

b) To fill joints and prevent dirt accumulation

c) To act as a waterproofing material

d) To level uneven surfaces 3 / 4

Rationale: Grout fills joints to prevent debris buildup and improve

appearance, not to bond tiles.

• Which tile type is least suitable for exterior freeze-thaw

environments?

a) Porcelain tile

b) Non-vitreous ceramic tile

c) Quarry tile

d) Fully vitrified porcelain

Rationale: Non-vitreous tiles absorb too much water, causing

cracking in freezing conditions.

• What should be done before tiling over an existing tile floor?

a) Apply sealer over old tiles

b) Ensure existing tiles are clean, sound, and properly bonded

c) Sand the surface lightly

d) Add a thick layer of mastic

Rationale: Proper substrate inspection ensures no loose or damaged

tiles that could compromise adhesion.

• Which of the following best describes “lippage”?

a) Uneven grout color

b) Variation in tile height between adjacent tiles

c) Tile spacing too wide

d) Bond failure at corners

• / 4