C-54 Ceramic and Mosaic Tile exam questions, with answers
10 practice questions for the CSLB Ceramic and Mosaic Tile trade exam, each with the answer, a plain explanation and the source it rests on.
These are not real exam questions. CSLB does not release its test questions or answer keys, and nobody else has them. We write our own questions from the C-54 outline and the codes, standards and references CSLB lists for the exam. Each answer names its source so you can check it.
The C-54 exam has 5 sections. The questions below are grouped by section, with the share of the exam each one carries. Read the question, pick an answer, then open “Show the answer”. The other questions of the free test, scored section by section, are in the free 25-question C-54 test.
Planning and Estimating · 18% of the exam
Review plans and specifications; select materials; estimate material quantities and costs.
1. A general contractor asks your C-54 company to bid several items on a commercial building. Under the CSLB classification text for ceramic and mosaic tile contractors, which item falls outside the C-54 classification?
- Thin tile that resembles full brick on a lobby wall
- Natural stone slabs for bathtub and shower walls
- Glass mosaic tile set on a lobby feature wall
- Hollow structural partition tile for interior walls
Show the answer
Answer: D. The C-54 classification covers glazed wall, ceramic, mosaic, quarry, paver, faience, glass mosaic and stone tile, thin brick-look tile, and stone slabs for tubs, showers and horizontal surfaces inside buildings. It expressly excludes hollow or structural partition tile, so that item belongs to another classification.
2. You are reviewing a federal project manual that follows the VA master specification for ceramic tiling (Section 09 30 13). The tile section does not list tile sizes, patterns or grout colors. Under that specification, where are these choices specified?
- Section 07 95 13, Expansion Joint Cover Assemblies
- Section 07 92 00, Joint Sealants
- Section 01 33 23, Shop Drawings and Samples
- Section 09 06 00, Schedule for Finishes
Show the answer
Answer: D. The VA ceramic tiling section points to Section 09 06 00, Schedule for Finishes, for the color, texture, pattern and size of field tile and trim shapes and the grout color. Section 01 33 23 only sets how submittals and samples are sent, 07 92 00 covers joint sealants, and 07 95 13 covers preformed expansion joints in tile floors.
Source: VA 09 30 13, Part 1 Related Work, VA Master Specification 09 30 13 Ceramic/Porcelain Tiling
Preparation for Tile and Stone Installation · 16% of the exam
Demolition, disposal and job site preparation; substrate preparation; membranes and barriers.
3. Before setting new tile, your crew must take up old vinyl sheet flooring glued down with black asphaltic cutback adhesive. Under the Resilient Floor Covering Institute's recommended work practices, which removal method is prohibited?
- Leaving the adhesive in place and covering it over
- Keeping the flooring wet while it is pried up
- Dry-sweeping and sanding off the leftover adhesive
- Cutting the sheet into strips with a utility knife
Show the answer
Answer: C. The RFCI warning says not to sand, dry sweep, dry scrape, drill, saw, beadblast or mechanically chip or pulverize old resilient flooring, backing, felt or cutback adhesive, because they may contain asbestos fibers or crystalline silica. Wet methods, hand cutting and leaving the adhesive in place avoid making dust.
4. A new concrete slab was treated with a silicate densifier. You put water droplets on the slab and they bead up instead of soaking in. Per Custom Building Products' bulletin on curing compounds, what should be done before thin-set or underlayment is applied?
- Prime the slab with a latex bonding primer only
- Wet the slab well and set tile while it is damp
- Shot blast or grind the slab to open up the surface
- Wipe the slab with a solvent and let it fully dry
Show the answer
Answer: C. The bulletin says that if water droplets do not penetrate a silicate-treated slab, the surface should be shot blasted or ground to open it up for cement mortar or underlayment. Wiping, priming or wetting the surface leaves the sealed layer in place, so the mortar still cannot key into the concrete.
Source: Custom TB92, silicate-treated slabs, Custom Building Products TB92 Concrete Curing Compounds
Installation and Repairs · 33% of the exam
Install tile and stone; joint treatment for tile and stone installations; repairs and restoration; showers and steam rooms.
5. Your crew is setting natural stone tile in an interior hallway that stays dry. Per the Ceramic Tile Education Foundation, what minimum mortar coverage is required under this stone tile?
- 80%
- 85%
- 90%
- 95%
Show the answer
Answer: D. CTEF states that ceramic tile needs 80% coverage in dry areas and 95% in wet and exterior areas, but natural stone tile needs 95% whether it is inside, outside, wet or dry. Using the 80% dry-area figure is the trap for stone.
Source: CTEF, mortar coverage (restating ANSI A108), CTEF blog: mortar coverage, trowel selection and mixing
6. A customer calls about an outdoor tiled patio where a white powder keeps coming back on the cement grout after each cleaning. Per the Ceramic Tile Education Foundation, what is this white deposit?
- Dissolved salts left behind when water evaporates
- Sealer residue that has turned white in the sunlight
- Grout haze left from cleaning too little after grouting
- Mildew growing on grout that stays wet in the shade
Show the answer
Answer: A. CTEF describes efflorescence as dissolved salts deposited on the surface of a porous material after the water that carried them evaporates. Water must keep reaching the salts for it to come back, so the lasting repair is to stop the moisture source, not just to keep scrubbing.
Source: CTEF, Understanding Efflorescence, CTEF blog: Understanding Efflorescence
Specialty Installations · 15% of the exam
Specialty tile installation; stone slab and countertop installation; accessories.
7. You are setting translucent glass mosaic tile on a shower wall. What kind of setting mortar do the Jeffrey Court / Oceanside glass tile installation instructions recommend?
- A gray mortar bed mixed with sand and lime
- A white thin-set mortar listed for glass tile
- A premixed organic adhesive (tile mastic)
- A gray thin-set mortar mixed with plain water
Show the answer
Answer: B. The glass tile instructions recommend white thin-sets for installing glass tile and list acceptable white products from several makers. Gray mortar shows through translucent glass, a sand-and-lime mortar bed is not a listed thin-set, and the instructions list organic adhesive (mastic) as unacceptable because of its low bond strength.
8. A client chose a polished marble kitchen countertop and asks what to watch for. According to the Natural Stone Institute's care article, what happens when marble contacts lemon juice or vinegar?
- It can etch, leaving a dull spot like a burn mark
- It can yellow, leaving a stain that bleach removes
- It can spall, with flakes coming off the slab edge
- It can craze, leaving fine cracks across the polish
Show the answer
Answer: A. NSI explains that marble is a calcium-based stone, and anything acidic can etch it, which looks like a dull spot or burn mark. Kitchen acids such as citrus, juices and vinegar are the usual cause; crazing, spalling and yellowing are not what the article describes.
Source: NSI, marble countertop care, Natural Stone Institute (usenaturalstone.org): Marble Countertop Care
Safety · 18% of the exam
Personnel safety; job site safety.
9. Your crew is cutting and setting pavers on an outdoor patio in summer. Under Cal/OSHA's heat illness standard (Title 8 §3395), above what outdoor temperature must shade be present at all times while employees are there?
- 75 degrees Fahrenheit
- 80 degrees Fahrenheit
- 85 degrees Fahrenheit
- 95 degrees Fahrenheit
Show the answer
Answer: B. Section 3395(d)(1) requires shade to be present when the outdoor temperature in the work area exceeds 80 degrees Fahrenheit. At or below 80 degrees the employer may instead provide timely access to shade on request; 95 degrees is the trigger for the high-heat procedures, not for shade.
10. Your wet saw is plugged into a temporary 120-volt, 20-ampere receptacle on a construction site; the receptacle is not part of the building's permanent wiring. Under Title 8 §2405.4, how must employees on the site be protected?
- By GFCI protection or an assured equipment grounding program
- By a two-wire cord that is kept off the wet floor
- By a 30-ampere breaker on the temporary power panel
- By a heavy-duty extension cord with a three-prong plug
Show the answer
Answer: A. Section 2405.4 requires construction employers to use ground-fault circuit interrupters, an assured equipment grounding conductor program, or both; all 120-volt, single-phase 15- and 20-ampere temporary receptacles in use by employees need approved GFCIs. A heavier cord, a larger breaker or keeping the cord dry does not meet the rule.
Where to go from here
How the license works, from experience to fees: how to get a C-54 license. Everything about the course: the C-54 exam page.
Questions from our free C-54 test, written from CSLB License Examination Study Guide, Ceramic and Mosaic Tile (C-54), form 13E-54 (03-2026). CSLB notes that the percentages are approximate. Reviewed 14 October 2026. Study guidance only; we are not affiliated with CSLB or PSI.