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 tile contractor will cut painted walls in a preschool built in 1972. Which federal rule applies?

• a.The asbestos NESHAP only
• b.No rule; it is not housing
• c.The EPA RRP rule✓
• d.Only the OSHA noise rule

The RRP rule covers renovations for pay in pre-1978 housing and child-occupied facilities such as preschools. It is tempting to think only homes are covered.40 CFR 745 Subpart E

What is the title of the EPA pamphlet renovators must give owners before pre-1978 renovation work?

• a.Renovate Right✓
• b.Lead-Safe Homes
• c.Protect Your Family
• d.Know Your Tile

The rule's pamphlet is Renovate Right: Important Lead Hazard Information for Families, Child Care Providers and Schools, delivered no more than 60 days before work.40 CFR 745.83-.84

When vacuuming floors after removing presumed-asbestos vinyl tile, what floor tool must the HEPA vacuum use?

• a.Any tool with a HEPA bag
• b.A rotating brush head
• c.A metal tool, no brush✓
• d.A carpet beater bar

Cal/OSHA requires HEPA vacuums with a disposable bag and a metal floor tool, no brush. A brush head is the tempting default, but the order specifies a metal floor tool with no brush.8 CCR 1529(g)(8)

On a construction site, what does Cal/OSHA require for combustible debris inside the building?

• a.Storage in an open pile
• b.Removal at project completion
• c.Burning on site daily
• d.Prompt removal✓

Combustible debris accumulated inside the building shall be removed promptly during construction. Waiting until completion is the tempting shortcut.8 CCR 1513(d)

A floor will receive 16 × 16 inch tile. What flatness does ANSI A108.02 require over 10 feet?

• a.3/8 inch
• b.1/4 inch
• c.1/2 inch
• d.1/8 inch✓

Tile with an edge 15 inches or longer requires 1/8 inch in 10 feet and 1/16 inch in 2 feet. 1/4 inch applies only to smaller tile.ANSI A108.02-4.1.4.3.1 via CTEF

Water dropped on a clean slab soaks in immediately. What does that indicate?

• a.A curing compound is present
• b.The slab needs acid etching
• c.The slab is too wet to tile
• d.It is receptive to mortar✓

Water that penetrates immediately indicates the concrete needs minimal preparation. Beading would suggest a sealer or curing compound.CTEF, bond breakers

Before pouring a self-leveling underlayment, what must be applied to the prepared surface?

• a.The SLU maker's primer✓
• b.Thin-set as a bonding layer
• c.A coat of sealer
• d.Water until it stands

SLUs require a properly prepared surface primed with the manufacturer's recommended product and allowed to dry. Standing water is a bond breaker.CTEF, SLU requirements

What thickness range do cement-based self-leveling underlayments cover, according to industry guidance?

• a.1 to 2 inches only
• b.Over 6 inches only
• c.1/16 inch to 6 inches✓
• d.1/4 to 1/2 inch only

Cement-based SLUs can be installed from as thin as 1/16 inch up to 6 inches, depending on the product.CTEF, underlayment guide

Under the TCNA stone method over wood (F250 STONE), what is the minimum plywood subfloor thickness?

• a.15/32 inch
• b.1/4 inch
• c.3/8 inch
• d.19/32 inch✓

F250 STONE calls for a tongue-and-groove plywood subfloor at least 19/32 inch thick, plus a second underlayment layer. 15/32 inch is the residential underlayment layer.TCNA F250 via CTEF

How are the joints between cementitious backer units treated under the VA specification?

• a.Fiberglass tape and mortar✓
• b.Left open for movement
• c.Paper tape and drywall mud
• d.Silicone sealant only

Joints and corners are filled with latex-portland cement mortar and covered with fiberglass tape embedded in the same mortar. Drywall mud is not a tile substrate treatment.VA 09 30 13

What total thickness of scratch and leveling coats does the VA specification allow over solid backing?

• a.1/8 to 1/4 inch
• b.3/8 to 5/8 inch✓
• c.5/8 to 3/4 inch
• d.1 to 1-1/2 inches

Over solid backing the coats total 3/8 to 5/8 inch; over metal lath on studs, 5/8 to 3/4 inch.VA 09 30 13

In which three forms do waterproof membranes for tile come, according to industry guidance?

• a.Wax, oil and resin
• b.Liquid, fabric and sheet✓
• c.Paper, felt and foil
• d.Grout, caulk and paint

Waterproof membranes come as liquid-applied, fabric-reinforced and sheet products, each designed to bond, support tile and stop water.CTEF, wet areas

Under the VA liquid-membrane procedure, how far up the walls is the membrane turned?

• a.At least 1 inch
• b.Only to the cove joint
• c.At least 4 inches✓
• d.At least 12 inches

The membrane is extended over drain flashing rings and turned up vertical surfaces not less than 4 inches above the finish floor.VA 09 30 13

What nominal thickness does the federal specification give for a chlorinated-polyethylene crack isolation sheet?

• a.0.030 inch✓
• b.0.125 inch
• c.0.010 inch
• d.0.040 inch

The federal specification lists 0.030 inch for the CPE crack isolation membrane and 0.040 inch for the CPE shower waterproof membrane.UFGS 09 30 10

Under TCNA's residential exposure classes, which is an example of a Res3 (wet) surface?

• a.A dining room wainscot
• b.A dry hallway floor
• c.A tub-shower wall✓
• d.A fireplace hearth

Res3 includes shower floors and tub and shower walls: surfaces soaked or frequently wet. A hallway floor is not a wet surface.TCNA Handbook via CTEF

Paint overspray is found on a slab that will receive tile. Which removal approach does industry guidance reject?

• a.Photographing and reporting it
• b.Citrus or solvent cleaners✓
• c.A change order for the removal
• d.Mechanical removal after an RFI

Industry guidance says solvents and citrus cleaners should never be used because they drive the residue deeper. Reporting and a change order are the recommended path.CTEF, bond breakers

Which is one of the three jobs thin-set mortar does in a tile assembly?

• a.Levels an uneven slab
• b.Supports the tile✓
• c.Waterproofs the substrate
• d.Colors the grout joint

Mortar bonds to the substrate, supports the tile and bonds to the tile back. It is not a leveling or waterproofing material.CTEF, troweling

What happens during the slaking step of mixing mortar?

• a.The mix rests✓
• b.Latex is poured on top
• c.Extra water is added
• d.It is mixed at high speed

Mixing has three phases: initial mix, slaking (the materials rest) and remixing. Adding water during slaking changes the mix the maker designed.CTEF, mixing

An installer mixes thin-set at high drill speed. What problem does industry guidance warn about?

• a.Better flow into the notches
• b.Air whipped in, weakening it✓
• c.No effect on strength
• d.Faster curing and better bond

Speeds above about 300 rpm can whip or entrain air, making the mortar light and weak. Faster mixing does not improve bond.CTEF, mixing

What minimum mortar thickness must remain between tile and backing after the tile is beaten in?

• a.3/32 inch✓
• b.1/4 inch
• c.1/2 inch
• d.1/32 inch

The ANSI method requires sufficient mortar for a minimum of 3/32 inch after embedding. 1/4 inch is the typical maximum for thin-set.ANSI A108.5 via CTEF

For 8 × 48 inch planks, which way should the trowel ridges run?

• a.In circles
• b.Diagonally
• c.Parallel to the 48-inch side
• d.Parallel to the 8-inch side✓

Ridges run in the same direction as the short side so trapped air has the shortest path to escape.CTEF, troweling

What minimum coverage applies to porcelain tile on an exterior wall?

• a.85 percent
• b.80 percent
• c.70 percent
• d.95 percent✓

ANSI A108.5 raises the 80 percent minimum to 95 percent on exterior and shower installations.ANSI A108.5 via CTEF