CSLB C-54 Ceramic and Mosaic Tile (Trade Exam) — All Questions

A customer approves a physical mockup of a tile range that has strong shade variation. What step best protects the contractor afterward?

• a.Taking the approval by phone at the supplier counter
• b.Keeping a photo of the mockup on the installer's phone
• c.Having the sales rep initial the carton labels
• d.A signed, dated approval on the sample✓

A signed and dated mockup is written proof that the customer accepted the whole range of shades. A phone approval leaves nothing on paper, a private photo does not show the customer agreed, and a rep's initials on cartons only identify product.CTEF, shade variation (mockup approval)

On arrival, a tile setter finds a slab well outside ANSI flatness tolerance. What puts the architect and general contractor on notice in writing?

• a.A remark to the site foreman during the walk-through
• b.A punch-list item written after the tile is set
• c.A product data sheet for the tile
• d.A request for information (RFI) stating the problem✓

An RFI records in writing that work will not start until the surface is within tolerance. A spoken remark can be denied later, a punch-list entry after setting is too late to protect the installer, and product data say nothing about the substrate.CTEF, lippage hazards (RFI)

Repairs to a damaged substrate are needed that the contract did not include. What should the contractor have in hand before starting that extra work?

• a.The owner's spoken go-ahead
• b.A note in the daily log
• c.A signed change order✓
• d.A revised delivery ticket for the tile

A signed change order authorizes and prices the added work. A spoken go-ahead and a log entry are not signed agreements, and a delivery ticket concerns materials, not scope or price.CTEF, substrate preparation (change orders)

Under the federal tile specification, when does tile work begin relative to mechanical and electrical rough-in?

• a.Before rough-in, so pipes can be fitted around the tile
• b.While rough-in is still under way, to save time
• c.After all fixtures have been set and trimmed out
• d.After rough-in is completed and tested✓

The specification says not to start tile work until rough-in for mechanical and electrical work is completed and tested. Tiling first or in parallel would force cutting finished work, and waiting for fixtures to be set delays the tile longer than the specification requires.UFGS 09 30 10, sequencing

An installer arrives and finds the substrate conditions unsatisfactory. What does the ANSI installation standard say about proceeding?

• a.Work does not proceed until satisfactory conditions are provided✓
• b.Work starts and the defects are noted for later repair
• c.Work starts if the owner accepts the risk verbally
• d.Work starts on the finish tile and the base is fixed after

The standard says installation work shall not proceed until satisfactory conditions are provided. Starting and recording the defects, taking a verbal acceptance, or tiling first and fixing the base later each put tile on a surface that has already been judged unfit.ANSI A108.02 via CTEF

A job needs forty cartons of a single tile color, and a supplier offers two lots from different sources. What does the federal tile specification require?

• a.Each type and color of tile from one source✓
• b.Any source, so long as the nominal size matches
• c.Two sources, if the lots are stored apart
• d.A second source, but only for cut pieces

The specification asks that each type and color of tile come from a single source, with mortar, adhesive and grout also matched to one source. Matching size alone does not control color or blend, separate storage does not change the source, and cut pieces are not exempt.UFGS 09 30 10, quality assurance

According to CSLB's C-54 study guide resource list, which organization publishes the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation?

• a.National Tile Contractors Association
• b.Tile Council of North America, Inc.✓
• c.Natural Stone Institute
• d.International Code Council

The resource list names Tile Council of North America, Inc. as the publisher of the TCNA Handbook. The National Tile Contractors Association publishes the NTCA Reference Manual, the Natural Stone Institute publishes the Dimension Stone Design Manual, and the International Code Council publishes the California Building Code.CSLB C-54 study guide 13E-54 (resources)

Which air-quality rule does the federal tile specification name for the VOC content of adhesives and sealants?

• a.ASTM C648 breaking-strength testing
• b.ANSI A137.1 water-absorption classes
• c.SCAQMD Rule 1168, one of two accepted paths✓
• d.40 CFR 745 lead renovation requirements

The specification accepts either CDPH Section 01350 emission limits or the VOC content limits of SCAQMD Rule 1168. ASTM C648 tests tile breaking strength, ANSI A137.1 sets tile water-absorption classes, and 40 CFR 745 is the lead renovation rule.UFGS 09 30 10

Plans show a shower receptor. Which California code listed in CSLB's C-54 study guide covers the drain and trap for it?

• a.The California Electrical Code
• b.The California Energy Code
• c.The California Fire Code
• d.The California Plumbing Code✓

The study guide lists the 2025 California Plumbing Code, and plumbing code governs shower drains and traps. An electrical code covers wiring, an energy code covers efficiency, and a fire code covers fire safety, none of them drain sizing.CSLB C-54 study guide 13E-54; CPC

Under the federal tile specification, what is the lowest substrate and ambient temperature at which ceramic tile work may be performed, and rising?

• a.40 degrees F
• b.32 degrees F
• c.50 degrees F✓
• d.65 degrees F

The specification bars ceramic tile work unless substrate and ambient temperature are at least 50 degrees F and rising, and keeps that temperature for 7 days after. 40 and 32 degrees F are too cold for mortar to cure, and 65 degrees F is stricter than the stated minimum.UFGS 09 30 10, environmental conditions

Before tile is installed, which condition do industry guidance and the standards require so lippage can be judged fairly?

• a.Permanent lighting installed✓
• b.Temporary work lights on stands
• c.A flashlight held low across the floor
• d.Daylight from the open windows

Finished installations are evaluated under the permanent intended lighting, so that lighting must be in place before setting. Work lights, a raking flashlight and window light alone each exaggerate or hide the surface differently.CTEF, lippage hazards

Which publication from the Natural Stone Institute does CSLB's C-54 study guide list?

• a.NTCA Reference Manual for tile contractors
• b.TCNA Handbook for tile installation
• c.2025 California Building Code
• d.Dimension Stone Design Manual✓

The resource list names the Natural Stone Institute's Dimension Stone Design Manual for stone work. The NTCA Reference Manual and TCNA Handbook are the tile-installation references, and the Building Code is a separate code book.CSLB C-54 study guide 13E-54 (resources)

Which edge type has the tightest warpage allowance in the industry warpage table?

• a.Natural
• b.Rectified✓
• c.Calibrated
• d.The three edge types share one limit

Rectified tile is allowed about 0.05 inch of warp each way, calibrated about 0.08 inch and natural about 0.12 inch. Natural has the loosest range, calibrated sits in the middle, and the limits do differ by edge type.CTEF, warped tile

A tile range rated V4 for shade variation will look like which of these?

• a.A very uniform appearance from tile to tile
• b.Slight variation that fits one narrow shade range
• c.Identical shade within one production lot
• d.Random color or texture that varies widely✓

V4 means substantial variation, where one tile can look completely different from another. V0 is the very uniform rating, and slight or lot-matched shade is a lower rating, so a V4 range should be viewed before it is chosen.CTEF, shade variation (V0-V4)

What minimum breaking strength does the federal tile specification set for floor tile, tested under ASTM C648?

• a.125 pounds
• b.57 pounds
• c.500 pounds
• d.250 pounds✓

The specification gives 250 pounds (113 kg) for floor tile. 125 pounds is the wall-tile figure, 57 is the wall-tile figure written in kilograms, and 500 pounds is not a value in the specification.UFGS 09 30 10; ASTM C648

A tile tests at 2 percent water absorption. Into which class does it fall?

• a.Impervious
• b.Semi-vitreous
• c.Non-vitreous
• d.Vitreous✓

Vitreous tile absorbs 0.5 to 3.0 percent. Impervious is below 0.5 percent, semi-vitreous is 3.0 to 7.0 percent, and non-vitreous is 7.0 percent or more.UFGS 09 30 10; ANSI A137.1

Where does industry guidance allow organic adhesive (mastic) to be used?

• a.On walls only✓
• b.On floors and curbs
• c.Over a waterproof membrane
• d.Inside steam rooms

Guidance restricts organic adhesive to walls and warns against using it on floors or curbs, over membranes or other impervious substrates, or in areas above 140 degrees F, which rules out steam rooms.CTEF, wet areas; ANSI A136.1

The federal tile specification's note describes which wear class for airport and mall walkways?

• a.Class 0
• b.Class V✓
• c.Class III
• d.Class I

Class V is heavy commercial traffic, with airports and malls as examples. Class 0 is generally for walls, and Class III is heavy residential or light commercial such as kitchens and hallways with limited outside traffic. Class I is a lighter class than the one named for such traffic.UFGS 09 30 10, PEI classes

For VA stone flooring, what minimum abrasion resistance value is set for slate compared with all other stone?

• a.10 for slate and 8 for every other stone
• b.8 for every stone including slate
• c.12 for slate and 10 for every other stone
• d.8 for slate and 10 for every other stone✓

The note says to use an abrasion resistance value of 8 for slate and 10 for all other stone materials. Reversing the values, using one value for every stone, or raising slate to 12 each misstate the note.VA 09 63 40

A kitchen backsplash is 14 ft long and 18 inches high, with a 2 ft wide window opening running the full height that will not be tiled. What is the tiled area?

• a.18 ft²✓
• b.21 ft²
• c.12 ft²
• d.252 ft²

The tiled length is 14 − 2 = 12 ft, and 12 × 1.5 ft = 18 ft². 21 ft² forgets the window, 12 ft² is the tiled length with no height applied, and 252 multiplies feet by inches.NIST Handbook 44, App. C (units)

How many 4 x 16 inch tiles should be ordered for a 10 ft by 8 ft wall if 12 percent is added for waste?

• a.180
• b.202✓
• c.90
• d.224

A 4 x 16 tile is 64 in², or about 0.444 ft². The wall is 80 ft², and with waste 80 × 1.12 = 89.6 ft², which needs 89.6 ÷ 0.444 = 202 tiles. 180 leaves out the waste, 90 is the area with waste rounded and never converted to tiles, and 224 divides by a rounded 0.4 ft² tile.NIST Handbook 44, App. C (144 in² = 1 ft²)

A floor needs 300 ft² of tile, and 330 ft² is ordered. What waste percentage does the order include?

• a.30 percent
• b.9.1 percent
• c.10 percent✓
• d.1.1 percent

The extra is 330 − 300 = 30 ft², and 30 ÷ 300 = 10 percent of the needed area. 30 percent reads the extra square feet as a percent, 9.1 percent divides by the ordered amount instead of the needed amount, and 1.1 is the multiplier, not a percentage.Estimating arithmetic

Labor is priced at $6.50 per ft² and materials at $4.25 per ft². What is the total for 320 ft²?

• a.$3,440✓
• b.$1,360
• c.$2,080
• d.$10.75

The combined rate is $10.75 per ft², and 320 × $10.75 = $3,440. $1,360 counts materials only, $2,080 counts labor only, and $10.75 is the unit rate, not the job total.Estimating arithmetic

A room is 8 ft by 10 ft with a 3 ft door opening. Cove base comes in 12 inch pieces, and a 10 percent waste allowance applies. How many pieces are needed?

• a.37✓
• b.33
• c.36
• d.40

The perimeter is 36 ft, less the 3 ft opening is 33 ft, and 33 × 1.10 = 36.3, which rounds up to 37 pieces. 33 skips the waste, 36 ignores both the door and the waste, and 40 adds waste but forgets the door deduction.Estimating arithmetic

A manufacturer states that one bag of mortar covers 80 ft² with the chosen trowel. How many bags does a 590 ft² floor need?

• a.7
• b.8✓
• c.9
• d.6

590 ÷ 80 = 7.4, and partial bags cannot be bought, so 8 are needed. 7 rounds down and runs short, 9 adds an unneeded bag, and 6 comes from dividing by a rounded 100 ft² per bag.Estimating arithmetic

Two installers each set 35 ft² per hour. How many hours does a 770 ft² floor take if they work together?

• a.22 hours
• b.5.5 hours
• c.44 hours
• d.11 hours✓

Together they set 70 ft² per hour, and 770 ÷ 70 = 11 hours. 22 hours is one installer's time, 5.5 halves the correct time again, and 44 divides by half of a single installer's rate.Estimating arithmetic

A floor mortar bed covers 360 ft² at 1-1/4 inch thick. About how many cubic yards of mortar is that, to the nearest tenth?

• a.37.5 yd³
• b.4.2 yd³
• c.0.7 yd³
• d.1.4 yd³✓

1-1/4 inch is about 0.104 ft, so 360 × 0.104 = 37.5 ft³, and 37.5 ÷ 27 = 1.4 yd³. 37.5 forgets to convert cubic feet to yards, 4.2 divides by 9 (the square-yard factor), and 0.7 uses half the thickness.NIST Handbook 44, App. C (27 ft³ = 1 yd³)

Who can remove the presumption that old resilient flooring and its mastic contain asbestos?

• a.The tile contractor, by visual inspection of the material
• b.The flooring dealer who sold the material
• c.An industrial hygienist, by recognized analysis✓
• d.The building owner, by written statement that it is safe

Section 1529 treats resilient flooring, mastic and backing as asbestos-containing unless an industrial hygienist determines otherwise by recognized analysis. Visual judgement, a dealer's word and an owner's statement are not analytical determinations.8 CCR 1529

After removing presumed asbestos-containing vinyl tile, which cleanup method is prohibited?

• a.Dry sweeping✓
• b.Wet wiping of the floor
• c.HEPA vacuuming with a metal floor tool
• d.Wetting the area during scraping of adhesive

Section 1529 prohibits dry sweeping for this work. Wet methods, a HEPA-filtered vacuum with a metal floor tool and no brush, and wet scraping of adhesive are the permitted practices.8 CCR 1529

Who must supervise Class II asbestos work, such as removing asbestos-containing floor tile?

• a.A competent person✓
• b.A certified lead renovator
• c.A C-22 contractor's apprentice
• d.A building inspector present for the day

Section 1529 requires all Class II work to be supervised by a competent person as defined in the section. A lead renovator is certified under a different federal rule, an apprentice has no defined supervisory qualification, and a building inspector does not run the work.8 CCR 1529

Under the Contractors State License Law, what amount of asbestos-containing material in asbestos-related work calls for a C-22 license or a qualifier who passed the asbestos certification exam?

• a.100 square feet or more✓
• b.10 square feet or more
• c.50 square feet or more
• d.1,000 square feet or more

The law bars a contractor from asbestos-related work involving 100 square feet or more of asbestos-containing surface area without that license or certification. The statute excepts vinyl asbestos floor materials from the certification-exam requirement, but Cal/OSHA work rules still apply to them. The smaller and larger figures are not the statutory line.Contractors License Law, B&P Code 7058 series (2026 Law Book)

Under the federal lead renovation rule, how much painted interior surface per room can be disturbed and still count as minor repair and maintenance?

• a.1 square foot or less
• b.20 square feet or less
• c.100 square feet or less
• d.6 square feet or less✓

The rule's minor-repair definition is 6 square feet or less per room indoors. 20 square feet is the exterior figure, while 1 and 100 square feet are not the rule's thresholds.40 CFR 745.83

A crew wants to toss broken tile from an upper window into a ground-level bin. Under Cal/OSHA's construction orders, when is that allowed?

• a.When the crew shouts a warning first and watches the drop zone for people
• b.After normal working hours when the site is empty
• c.When the bin is covered with plywood
• d.Only when the landing area is guarded by barricades or similar means✓

Section 1513 bars throwing waste, materials or tools from buildings to areas where employees may be unless the fall area is guarded. A shout, the hour of day or a covered bin does not keep people out of the drop zone.8 CCR 1513

Where should a crew place waste solvents and other flammable job-site wastes?

• a.In the regular debris pile until the end of the working shift
• b.In open buckets kept beside the saw
• c.In covered containers kept separate from normal debris✓
• d.In the dumpster along with the broken tile and other debris

Section 1513 calls for flammable or hazardous wastes to go in covered containers separate from normal debris. Mixing them in a debris pile, leaving them open, or putting them in the general dumpster defeats that separation.8 CCR 1513

Before saw cutting or breaking a slab-on-grade for a plumbing change, what should be verified?

• a.Whether it is a post-tension slab✓
• b.Whether the slab is more than 4 inches thick
• c.Whether the slab has a curing compound
• d.Whether the slab has radiant tubing

A city bathroom-remodel handout warns that cutting a tendon in a post-tension slab can be dangerous to life and costly to repair. Thickness, curing compound and tubing matter for other reasons but are not the hazard that handout flags.City of Milpitas bathroom-remodel handout (2025 codes)

In a bathroom tile remodel, the tub shows small chips before work starts. What does industry guidance advise?

• a.Photograph the defects and tell the owner in writing✓
• b.Say nothing, since the tub will be covered by a drop cloth
• c.Mention it to the owner in passing
• d.Repair the chips first with leftover thin-set mortar from the job

Guidance says to inspect the tub, take photos and report defects in writing, because an installer who starts without notice may end up paying to repair or replace the tub. Silence and a casual mention leave no record, and mortar is not a tub repair material.CTEF, tub protection

Before its employees arrive at a construction site, what must the employer do about site conditions?

• a.Order a safety inspection from the city building department
• b.Wait for the first injury report to show what the hazards are
• c.Make a thorough survey of the site for predictable hazards✓
• d.Hand out the Code of Safe Practices at the gate

Section 1511 requires a thorough survey of the site before employees are present to determine predictable hazards and the safeguards needed. No city inspection is required for this, waiting for an injury is the opposite of prevention, and handing out the Code does not identify site hazards.8 CCR 1511

The federal tile specification lists a floor tolerance for dry-set mortar installations. What is it?

• a.1/4 inch in 10 feet
• b.1/16 inch in 3 feet
• c.1/8 inch in 10 feet✓
• d.1/8 inch in 8 feet

For dry-set mortar floors the specification gives 1/8 inch in 10 feet. 1/4 inch in 10 feet is the VA allowance for a portland cement mortar bed, 1/16 inch in 3 feet is the organic adhesive floor figure, and 1/8 inch in 8 feet is the wall figure.UFGS 09 30 10

A floor slopes evenly 1 inch over 12 feet but has no high or low spots. In tile terms, it is:

• a.Level but not flat
• b.Flat but not level✓
• c.Both flat and level
• d.Neither flat nor level

In tile work, flat means no significant high or low spots, and level means parallel to a true horizontal plane. An even slope is flat and not level, so tile can sit on it without lippage.CTEF, flat vs level

What must grinding equipment be fitted with when preparing a substrate for tile?

• a.A water nozzle that wets the slab down with slurry
• b.A bonnet that sends dust to an approved HEPA vacuum✓
• c.A dry broom attachment that sweeps dust aside
• d.A cloth sleeve that holds the dust loosely

Industry guidance says grinders must have the appropriate bonnet to capture dust and send it to an attached, approved HEPA vacuum. A water nozzle only makes slurry, a broom attachment moves dust around, and a cloth sleeve does not filter fine dust.CTEF, substrate patching

A new slab has curing compound on it. Which preparation method does industry guidance say properly removes it?

• a.Mopping with a citrus-based cleaner and rinsing
• b.Mechanical abrasion such as shot blasting✓
• c.Wiping with paint remover
• d.Brushing on a bonding sealer

Guidance names mechanical abrasion, such as shot or bead blasting, as the proper way to take off a thin layer along with the compound. Citrus cleaners and paint removers should never be permitted, and a sealer would simply add another bond breaker.CTEF, bond breakers

How should water be measured when mixing a self-leveling underlayment?

• a.By eye against the bucket line
• b.By adding it until the mix looks pourable
• c.In a measuring container✓
• d.By the same count as the last bag mixed

Guidance says accurately measuring the water in a measuring container is a must for self-leveling underlayment. Judging by eye, by pourability or by the previous bag's count gives an inconsistent mix.CTEF, self-leveling underlayment

Before any tile installation begins, what must be determined about the structure?

• a.That the finished floor is the same color as the walls
• b.That the mortar supplier has a local warehouse
• c.That the tile carton count matches the order
• d.That it can carry the added weight of the tile assembly✓

Guidance says the ability of the structure to carry the added weight of the tile assembly must be determined first. Color matching, warehouse location and carton counts do not address what the framing can support.CTEF, underlayment guide

Which ASTM standard does the VA specification cite for polyethylene sheet used as a cleavage membrane?

• a.ASTM D4397✓
• b.ASTM C648
• c.ASTM C847
• d.ASTM C1026

The specification cites polyethylene sheet conforming to ASTM D4397. C648 is breaking strength of tile, C847 is metal lath, and C1026 is the freeze-thaw test for exterior tile.VA 09 30 13

Which of these is a requirement listed for a waterproof membrane under tile?

• a.It must absorb water into its fabric
• b.It must stay loose-laid under the mortar bed
• c.It must bond tenaciously to the protected surface✓
• d.It must add texture to the finished tile surface

Guidance lists bonding tenaciously to the protected surface, supporting the weight of the tile and preventing water from entering the substrate. Absorbing water defeats the purpose, a loose-laid layer cannot support tile, and texture is not a membrane requirement.CTEF, wet areas

What shear bond strength must an uncoupling membrane reach in seven days under the test cited for these products?

• a.50 psi or greater✓
• b.25 psi or greater
• c.100 psi or greater
• d.400 psi or greater

Uncoupling membranes are not covered by ANSI or ISO standards but must reach 50 psi or greater per the A118.12 test method. 25 psi is too low, and 100 and 400 psi are not the stated threshold (400 psi appears in guidance about glass tile bond).CTEF, underlayment guide

What tool helps an installer confirm the thickness of a liquid-applied waterproof membrane while it is still wet?

• a.A straightedge laid across the floor
• b.A wet film thickness gauge✓
• c.A moisture meter used on the slab
• d.A notched trowel

A wet film gauge reads the applied thickness before the coat cures. A straightedge checks flatness, a moisture meter checks substrate moisture, and a trowel does not measure film thickness.CTEF, wet areas

After the second coat, what total thickness does the VA specification give for a liquid-applied elastomeric membrane?

• a.5 to 8 mils
• b.10 to 20 mils
• c.100 to 150 mils
• d.50 to 75 mils✓

The first coat is 30 to 50 mils and the recoat brings the total to 50 to 75 mils (1.3 to 1.9 mm). The smaller ranges are far too thin, and 100 to 150 mils is double the stated total.VA 09 30 13

After a liquid-applied membrane cures, how does the VA specification test it for leaks?

• a.1/2 inch of water for 1 hour
• b.2 inches of water for 72 hours
• c.4 inches of water for 8 hours
• d.1 inch of water held for 24 hours✓

The VA test is 1 inch (25 mm) of water for 24 hours. The other depth and time pairs are not what that specification states.VA 09 30 13

Under the VA stone specification, how far must cleavage membrane be lapped at joints?

• a.At least 1 inch
• b.At least 2 inches
• c.At least 4 inches✓
• d.At least 12 inches

Cleavage membrane is placed over the substrate and lapped at least 100 mm (4 inches) at joints. 1 and 2 inches are too short to keep the bed separated, and 12 inches is more than the stated minimum.VA 09 63 40