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

A kitchen floor measures 7 ft 6 in. by 10 ft. What is its area?

• a.76 ft²
• b.75 ft²✓
• c.86 ft²
• d.70 ft²

7 ft 6 in. is 7.5 ft, and 7.5 × 10 = 75 ft². Reading 7 ft 6 in. as 7.6 ft gives 76 ft², the common error of treating inches as tenths of a foot.NIST Handbook 44, App. C (units)

How many 2 × 8 inch tiles cover one square foot, ignoring joints?

• a.16
• b.12
• c.8
• d.9✓

A 2 × 8 tile covers 16 square inches; 144 ÷ 16 = 9 tiles per square foot. 16 is the tile's area, not a tile count.NIST Handbook 44, App. C (144 in² = 1 ft²)

On a plan drawn at 1/2 inch = 1 foot, a wall measures 2-1/2 inches long. How long is the wall?

• a.10 ft
• b.2.5 ft
• c.1.25 ft
• d.5 ft✓

At 1/2 inch = 1 foot, each inch of paper is 2 feet, so 2-1/2 inches is 5 feet. 1.25 ft comes from dividing by 2 instead of multiplying.Plan scale arithmetic

A 320 ft² floor gets 12 × 24 inch tile with a 10 percent waste allowance. How many tiles are needed?

• a.160
• b.176✓
• c.352
• d.320

Each 12 × 24 tile covers 2 ft². 320 × 1.10 = 352 ft², and 352 ÷ 2 = 176 tiles. 352 is the square footage with waste, not the tile count.NIST Handbook 44, App. C

A job needs 188 ft² of tile including waste, and each carton holds 11.6 ft². How many cartons must be ordered?

• a.18
• b.17✓
• c.16
• d.11

188 ÷ 11.6 = 16.2, and partial cartons cannot be bought, so order 17. Rounding down to 16 leaves the job short.Estimating arithmetic

A 10 × 12 ft room gets cove base on all walls except a 3 ft door opening. How many linear feet of base are needed?

• a.44 lin ft
• b.120 lin ft
• c.38 lin ft
• d.41 lin ft✓

The perimeter is 2 × (10 + 12) = 44 ft; subtract the 3 ft opening for 41 linear feet. 120 is the room's area, not a linear measure.Estimating arithmetic

An installer lays 40 ft² per hour. How many hours does a 500 ft² floor take?

• a.12 hours
• b.12.5 hours✓
• c.8 hours
• d.20 hours

Hours equal area divided by production rate: 500 ÷ 40 = 12.5. Rounding to 12 drops half an hour of paid labor.Estimating arithmetic

A shower drain sits 30 inches from the farthest corner. At 1/4 inch per foot, how much must the pre-slope rise to that corner?

• a.1/4 inch
• b.1-1/4 inches
• c.7-1/2 inches
• d.5/8 inch✓

30 inches is 2.5 feet; 2.5 × 1/4 inch = 5/8 inch. 7-1/2 inches comes from multiplying 30 by 1/4 without converting inches to feet.Plumbing code slope as described by CTEF

A 4 × 6 ft shower floor gets a 1-1/2 inch mortar bed. What volume of mortar is that?

• a.36 ft³
• b.1.5 ft³
• c.3 ft³✓
• d.6 ft³

Area 24 ft² × 0.125 ft (1.5 in ÷ 12) = 3 ft³. 36 comes from multiplying by 1.5 without converting the thickness to feet.NIST Handbook 44, App. C

Which submittal shows the proposed tile pattern at inside and outside corners and around items mounted on the tile?

• a.Product data sheets
• b.Shop (detail) drawings✓
• c.Material certificates
• d.Warranty letter

Federal tile specifications ask for detail drawings showing the pattern at corners, terminations and mounted equipment. Product data describe materials, not how they are laid out.UFGS 09 30 10, submittals

Glazed ceramic wall tile made for interior walls typically falls in which water-absorption class?

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

Glazed wall tile is typically non-vitreous, absorbing 7 percent or more, and is recommended for walls only. Impervious describes porcelain.ANSI A137.1 via UFGS 09 30 10

A tile tested at 0.3 percent water absorption belongs to which class?

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

Impervious tile absorbs less than 0.5 percent; porcelain is typically impervious. Vitreous is 0.5 to 3.0 percent.ANSI A137.1 via UFGS 09 30 10

Under the federal tile specification's note, where should a tile with a wet DCOF below 0.42 be installed?

• a.Commercial kitchens
• b.Any level interior floor
• c.Floors kept dry in use✓
• d.Exterior walkways and ramps

The note says tiles under 0.42 wet DCOF should only be installed where the surface will be kept dry when walked upon, with safe cleaning procedures. A commercial kitchen is a floor expected to be walked on wet, where 0.42 is the threshold minimum.UFGS 09 30 10; ANSI A137.1

Where may 6 mm (1/4 inch) gauged porcelain tile be used, according to the federal tile specification's note?

• a.Floors, walls, counters✓
• b.Walls only
• c.Countertops only
• d.Exterior walls only

The note says 6 mm gauged porcelain is suitable for floors, walls and counter tops, while 3 mm is for walls only.UFGS 09 30 10 (ANSI A137.3/A108.19)

Tile arrives with opened cartons and torn labels. What does the federal specification require of delivered materials?

• a.Any cartons, if the tile is uncracked
• b.Resealed cartons with new labels
• c.Unopened containers with labels intact✓
• d.Loose tile on pallets

Materials are to be delivered in the manufacturer's original unopened containers with seals unbroken and labels intact. Resealing does not restore the identification.UFGS 09 30 10, delivery

Which ANSI standard covers an EGP (exterior glue plywood) modified dry-set mortar?

• a.A118.11✓
• b.A136.1
• c.A118.6
• d.A118.1

A118.11 is the EGP latex-portland cement mortar for plywood. A118.1 is unmodified dry-set mortar and A118.6 is standard cement grout.ANSI A118.11

A floor has 3/16 inch grout joints. Which grout type fits the joint width?

• a.Latex caulk
• b.Sanded grout✓
• c.Unsanded grout
• d.Organic adhesive

Sanded grout is used for joints 1/8 inch or wider; unsanded grout is for joints 1/8 inch or narrower.VA 09 63 40 spec note

Before bidding, a contractor finds the drawings show no movement joints in a large tile floor. What is the correct action?

• a.Omit them to match the drawings
• b.Send the designer an RFI✓
• c.Add grout joints at 40 feet
• d.Wait and ask the inspector

Movement joint locations are the design professional's call, so the gap goes to the architect in writing. Omitting them is the tempting reading of the drawings, but EJ171 treats movement joints as required.TCNA EJ171 via CTEF

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)