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NCCER Tile practice questions

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Question 1Tile Craft Fundamentals and Safety

On a tile jobsite, which practice best protects workers from silica dust produced when cutting cement backer board?

  1. Wearing a cloth face covering while dry cutting
  2. Cutting outdoors only on windy days
  3. Wet cutting or using a dust-collecting vacuum at the point of cut Correct answer.
  4. Cutting faster to reduce total exposure time

Explanation

Crystalline silica dust from cement backer board is a serious respiratory hazard, and effective control means stopping dust at the source. Wet cutting or attaching a dust-collecting vacuum to the tool at the point of cut is the recognized engineering control. Respirators are the last line of defense, not a substitute for source control.

Question 2Tile Craft Fundamentals and Safety

A tile setter is mixing thin-set mortar and the bag calls for a specific water ratio. Why should the mixer avoid adding extra water beyond the stated amount?

  1. Extra water weakens the bond and increases shrinkage and bond failure Correct answer.
  2. Extra water makes the mortar cure faster and harder
  3. Extra water has no effect once the mortar is mixed
  4. Extra water improves adhesion on dense porcelain tile

Explanation

Thin-set is a cementitious product engineered around a specific water-to-powder ratio. Adding water beyond the manufacturer's ratio dilutes the cement and polymer content, reducing bond strength and increasing shrinkage and cracking. The correct amount is measured, not judged by eye.

Question 3Tile Craft Fundamentals and Safety

Which personal protective equipment is most important when mixing dry mortar powder by hand?

  1. Hearing protection only
  2. A NIOSH-approved respirator and safety glasses Correct answer.
  3. Steel-toed boots only
  4. A hard hat only

Explanation

Dry mortar powder contains silica and alkaline cement dust that can damage lungs and eyes during mixing. A properly fitted respirator and eye protection address the primary inhalation and eye hazards. The other items protect against different hazards and do not cover dust exposure.

Question 4Tile Craft Fundamentals and Safety

What is the primary purpose of applying a waterproofing membrane in a shower installation before tile is set?

  1. To make the tile adhere more strongly to the wall
  2. To prevent moisture from reaching framing and substrates behind the tile Correct answer.
  3. To level uneven wall surfaces before tiling
  4. To reduce the weight of the installed assembly

Explanation

Tile and grout are not waterproof, so moisture that passes through them must be stopped before it reaches framing or sheathing. A waterproofing membrane creates that continuous barrier. Adhesion, leveling, and weight are separate concerns handled by other materials and methods.

Question 5Tile Craft Fundamentals and Safety

Why must tile be installed over a structurally sound, deflection-compliant substrate?

  1. Excess deflection causes cracks in tile and grout and can debond the assembly Correct answer.
  2. Deflection is only a concern for exterior installations
  3. Deflection improves the color consistency of grout
  4. Tile adhesive will not cure on any wood substrate

Explanation

Tile is rigid and brittle, so it cannot tolerate movement in the substrate beneath it. If the floor or wall deflects beyond the allowable limit for the installation, the tile and grout crack and the bond can fail. Deflection limits apply to interior and exterior work alike.

Question 6Tile Craft Fundamentals and Safety

A helper is instructed to keep mortar from drying out on the trowel. Which action best follows that instruction?

  1. Remix the mortar periodically and use it within its stated open time Correct answer.
  2. Spread mortar far ahead so it has time to set
  3. Add water to the mortar whenever it starts to stiffen
  4. Cover the trowel with a wet rag and continue working

Explanation

Mortar has a limited open time once mixed and spread, and it should be used within it. Remixing within the allowed pot life keeps the consistency workable without changing the mix design. Adding water after mixing or spreading ahead of the work causes weak, poorly bonded installations.

Question 7Tile Craft Fundamentals and Safety

During a layout, a setter finds the last row at a wall would be only 3/4 inch wide. What is the best practice?

  1. Shift the layout so equal cut tiles of at least half a tile appear at both opposing walls Correct answer.
  2. Increase the grout joint width to absorb the difference
  3. Start the layout from the opposite wall without adjusting
  4. Install the narrow cut as-is to save material

Explanation

Narrow slivers are difficult to cut, prone to breaking, and visually poor. Shifting the layout to split the difference produces balanced cuts on both sides that are each at least half a tile wide. Grout joints cannot absorb a difference of that size.

Question 8Tile Craft Fundamentals and Safety

Which trowel notch size should generally be selected for a given tile installation?

  1. Any notch, since notch depth does not affect coverage
  2. One matched to the tile size and substrate flatness per the mortar manufacturer Correct answer.
  3. The largest notch available to guarantee coverage
  4. The smallest notch to conserve mortar

Explanation

Mortar coverage depends on notch size, tile size, and how flat the substrate is. Manufacturers publish recommendations that pair notch size with tile dimensions and substrate condition. Choosing arbitrarily risks either poor coverage or excess mortar squeeze-out.

Question 9Tile Craft Fundamentals and Safety

What is the correct method for checking mortar coverage on a freshly set tile?

  1. Lift the tile and inspect the back for transferred mortar coverage Correct answer.
  2. Press down firmly and assume full coverage
  3. Tap the tile surface with a hammer
  4. Check the grout joints for excess mortar

Explanation

Coverage is verified by lifting a tile shortly after setting and observing how much of its back is coated with transferred mortar. Industry standards specify minimum coverage percentages for interior and exterior work. Tapping and visual inspection of joints do not reveal voids beneath the tile.

Question 10Tile Craft Fundamentals and Safety

A tile setter needs to cut a curved hole in a porcelain tile for a plumbing pipe. Which tool is most appropriate?

  1. A tile nipper
  2. A wet saw with a straight fence only
  3. A carbide scoring tool
  4. A diamond hole saw or angle grinder with a diamond blade Correct answer.

Explanation

Porcelain is very hard and requires diamond abrasives to cut cleanly. A diamond hole saw or an angle grinder fitted with a diamond blade can follow a curved or circular cut. Scoring tools, nippers, and straight fences are for straight cuts or soft tile.

Question 11Tile Craft Fundamentals and Safety

Why is back-buttering sometimes required when installing large-format tile?

  1. To eliminate the need for grout joints
  2. To achieve the required mortar coverage and avoid voids under the tile Correct answer.
  3. To speed up the curing of the mortar
  4. To make the tile lighter to handle

Explanation

Large-format tile is difficult to embed fully, and flat troweling mortar onto the tile back (back-buttering) helps fill voids and reach the required coverage. Voids lead to hollow spots, cracking, and bond failure. It does not change weight, cure speed, or joint requirements.

Question 12Tile Craft Fundamentals and Safety

What is the main reason for leaving a movement joint at the perimeter of a tile floor?

  1. To hide layout mistakes at the edges
  2. To allow grout to drain out during installation
  3. To allow the tile field to expand and contract independently of the walls Correct answer.
  4. To provide a place to anchor the tile to the wall

Explanation

Tile assemblies move with temperature and moisture changes, and perimeter movement joints let the field move without bearing against walls or restraining structures. Without them, tenting and cracking can occur. They are not for hiding errors or anchoring tile.

Question 13Tile Craft Fundamentals and Safety

When mixing thin-set, what does the term "slake" refer to?

  1. Letting the mixed mortar rest before a final remix Correct answer.
  2. Removing excess water from the surface
  3. Heating the water to speed curing
  4. Adding sand to stiffen the mix

Explanation

Slaking is the short rest period after initial mixing that allows the mortar's chemistry and moisture to equalize. A brief remix after slaking restores workability without adding water. Skipping it can leave lumps and inconsistent consistency.

Question 14Tile Craft Fundamentals and Safety

A worker must carry a stack of tile across a site. Which practice reduces the risk of musculoskeletal injury?

  1. Use a cart or carry smaller loads close to the body with proper lifting technique Correct answer.
  2. Twist at the waist while lifting to change direction
  3. Hold the load at arm's length for balance
  4. Carry the entire stack at once to reduce trips

Explanation

Tile is dense and awkward, so mechanical aids or smaller loads kept close to the body reduce strain on the back. Twisting while lifting and holding loads away from the body increase injury risk. Fewer trips do not justify overloading.

Question 15Tile Craft Fundamentals and Safety

Which condition most commonly causes efflorescence on grout in a shower?

  1. Moisture migrating through the assembly and depositing salts on the surface Correct answer.
  2. Grout that was mixed with too little water
  3. Use of a latex-modified grout
  4. Tile installed with too wide a grout joint

Explanation

Efflorescence is a white salt deposit left when water moves through cementitious material and evaporates at the surface. The underlying cause is moisture movement, often from a missing or failed waterproofing layer. Correcting the water source is the real fix.

Question 16Tile Craft Fundamentals and Safety

A setter is installing tile over a concrete slab with a visible crack. What is the appropriate first step?

  1. Increase the mortar thickness to bridge the crack
  2. Evaluate the crack and use an appropriate crack-isolation membrane or treatment Correct answer.
  3. Ignore the crack because concrete is rigid
  4. Fill the crack with grout and tile directly over it

Explanation

Cracks in a slab can transfer through a directly bonded tile assembly and crack the tile. The crack must be evaluated and an appropriate isolation or treatment method used per the manufacturer and standards. Simply covering it does not prevent transfer.

Question 17Tile Craft Fundamentals and Safety

Which statement correctly describes the difference between thin-set and mastic (organic adhesive)?

  1. Mastic is stronger than thin-set in all applications
  2. Thin-set requires no mixing and comes ready to use
  3. Thin-set is cement-based and suitable for wet areas; mastic is organic and limited in wet locations Correct answer.
  4. Mastic is cement-based and preferred in showers

Explanation

Thin-set is a cementitious mortar that performs well in wet and exterior conditions when properly specified. Mastic is an organic adhesive with limited tolerance for prolonged moisture and is generally restricted in showers and exteriors. The two are not interchangeable.

Question 18Tile Craft Fundamentals and Safety

A crew is setting tile on a wall and needs temporary support while the mortar cures. What is the best approach?

  1. Use spacers, wedges, or a ledger board to hold tile in position until the mortar sets Correct answer.
  2. Press the tile hard and release immediately
  3. Rely on the mortar's initial tack to hold the tile
  4. Set the wall tile from the top down without support

Explanation

Wall tile can slide under its own weight before the mortar develops enough strength to hold it. Spacers, wedges, or a ledger board keep courses aligned and in place during curing. Relying on tack alone leads to sagging and misalignment.

Question 19Tile Craft Fundamentals and Safety

Which factor most directly determines the required grout joint width for a tile installation?

  1. The number of workers on the crew
  2. Tile dimensional tolerances and the manufacturer's recommendations Correct answer.
  3. The color of the grout selected
  4. The brand of thin-set used

Explanation

Tile varies in size and squareness within a production run, and joint width must accommodate that variation to keep lines straight. Manufacturers publish minimum joint widths based on tile type and tolerance. Grout color, mortar brand, and crew size do not drive joint width.

Question 20Tile Craft Fundamentals and Safety

A setter notices hollow-sounding spots after installing tile on a floor. What is the most likely cause?

  1. Grout applied too soon after setting
  2. Use of a notched trowel
  3. Insufficient mortar coverage or voids beneath the tile Correct answer.
  4. Tile that was cut with a wet saw

Explanation

Hollow sounds indicate voids where mortar did not transfer to the tile back or substrate. This usually results from insufficient coverage, mortar that skinned over, or inadequate embedding. Cutting method and grout timing do not create hollow spots.

Question 21Tile Craft Fundamentals and Safety

Why do industry standards require a minimum mortar coverage percentage that is higher for exterior than for interior installations?

  1. Interior installations do not require any coverage
  2. Exterior tile faces greater moisture and freeze-thaw stress, so more complete bonding is needed Correct answer.
  3. Exterior mortar cures more slowly and needs more material
  4. Exterior tile is always larger than interior tile

Explanation

Exterior assemblies are exposed to water, temperature swings, and freeze-thaw cycling that stress the bond. Higher required coverage reduces voids where water can collect and freeze. Coverage requirements are not based on tile size or cure speed.

Question 22Tile Craft Fundamentals and Safety

A tile installation over a wood-framed floor shows tenting along a grout line several months after completion. Which cause is most consistent with this failure?

  1. Missing or inadequate movement joints allowed the tile field to expand against a restraint Correct answer.
  2. Grout was mixed with too much latex additive
  3. Tile was installed with a 1/4-inch notch trowel
  4. The tile was back-buttered during installation

Explanation

Tenting occurs when a tile field expands and has nowhere to go, so tiles lift and separate along grout lines. The usual cause is absent or inadequate movement joints at perimeters, transitions, or large field areas. Additives, notch size, and back-buttering do not produce tenting.

Question 23Tile Craft Fundamentals and Safety

When installing tile in a shower pan, why must the waterproofing be sloped and integrated with the drain assembly?

  1. So water reaching the membrane drains to the weep holes rather than pooling Correct answer.
  2. So the tile adheres directly to the drain flange
  3. So grout can bond to the membrane
  4. So the pan can be installed without a preslope

Explanation

Water inevitably reaches the waterproofing layer, so the membrane must slope toward the drain and connect to it so that water exits through the weep holes. Pooling water at the membrane leads to deterioration and efflorescence. Tile and grout are not part of the drainage path.

Question 24Tile Craft Fundamentals and Safety

A contractor is choosing between a cementitious backer board and a coated gypsum board for a tub surround. Which consideration is decisive?

  1. Cement board cannot be waterproofed
  2. Gypsum-based board is not suitable where it will be exposed to sustained moisture Correct answer.
  3. Cement board is lighter and easier to cut
  4. Gypsum board costs more per sheet

Explanation

Gypsum core board deteriorates when repeatedly wetted, so it is restricted to dry or limited-moisture areas depending on the product. Cementitious backer board tolerates moisture and is appropriate for wet areas when detailed correctly. Cost, weight, and waterproofing capability do not favor gypsum here.

Question 25Tile Craft Fundamentals and Safety

What is the primary safety concern when using a wet saw on an indoor jobsite?

  1. Dust generation from dry cutting
  2. Vibration transfer to the operator's hands
  3. Electrical shock risk from water near the motor and cord Correct answer.
  4. Excessive noise exposure

Explanation

Wet saws combine water and electricity, so ground-fault protection, intact cords, and proper plugging are essential. Water near the motor or a damaged cord can create a shock hazard. Noise, dust, and vibration are concerns with other tools or dry cutting.

Question 26Tile Craft Fundamentals and Safety

Which personal protective equipment is most important when mixing dry thin-set powder by hand with a hoe?

  1. Steel-toe boots
  2. A face shield
  3. Cut-resistant gloves
  4. A dust respirator Correct answer.

Explanation

Dry cementitious thin-set contains silica and other fine particles that become airborne during mixing. A NIOSH-rated dust respirator protects the lungs from inhalation of these particles. Other PPE is useful on site but does not address the primary hazard of mixing powder.

Question 27Tile Craft Fundamentals and Safety

Which substrate condition must be corrected before any tile is bonded to a concrete slab?

  1. A slab with a vapor retarder beneath it
  2. A fully cured slab older than 28 days
  3. A broom-finish surface texture
  4. Dust, curing compounds, and laitance Correct answer.

Explanation

Bonding requires a clean, sound, absorbent surface. Dust, curing compounds, and laitance form a weak layer that prevents the thin-set from gripping the slab. A broom finish and a properly cured slab are acceptable conditions, not defects.

Question 28Tile Craft Fundamentals and Safety

On a jobsite, what is the safest way to store boxes of tile before installation?

  1. Stacked flat and low, away from traffic paths Correct answer.
  2. Piled near the edge of an open floor opening
  3. Leaned upright against a wall in a walkway
  4. Stacked vertically in a doorway

Explanation

Tile boxes should be stored flat and low so the stack is stable and does not topple. Keeping them out of traffic paths prevents trips and collisions. Leaning or vertical stacking creates instability and blocking a doorway creates an egress hazard.

Question 29Tile Craft Fundamentals and Safety

Which tool is used to score and snap a glazed ceramic wall tile for a straight cut?

  1. A hole saw
  2. A manual tile cutter Correct answer.
  3. A grout float
  4. A wet saw

Explanation

A manual tile cutter scores the glaze with a carbide wheel and snaps the tile along the score line. It is the standard tool for straight cuts on ceramic wall tile. A wet saw is also used for cutting but is not the score-and-snap tool described.

Question 30Tile Craft Fundamentals and Safety

What does the term "pot life" mean for a mixed thin-set mortar?

  1. The time the mortar can sit on the substrate before setting tile
  2. The time allowed before grouting the tile
  3. The time the mixed mortar remains usable in the bucket Correct answer.
  4. The time the mortar needs to cure fully

Explanation

Pot life is the working time during which a mixed thin-set stays spreadable and effective in the bucket. Once it stiffens beyond its pot life it must be discarded, not revived with water. Cure time, grout timing, and open time are separate concepts.

Question 31Tile Craft Fundamentals and Safety

Which practice best protects workers from silica dust when dry-cutting tile with a grinder?

  1. Working in the same room with doors closed
  2. Wearing only safety glasses
  3. Cutting faster to reduce exposure time
  4. Using water suppression or a dust shroud with HEPA vacuum Correct answer.

Explanation

Silica dust from dry cutting is a serious respiratory hazard. Water suppression or a shroud connected to a HEPA vacuum controls the dust at the source. Cutting faster or closing the room increases exposure, and eye protection alone does nothing for the lungs.

Question 32Tile Craft Fundamentals and Safety

What is the purpose of a notched trowel in tile installation?

  1. To score tile before snapping
  2. To remove excess grout from joints
  3. To level the substrate before tiling
  4. To spread thin-set in uniform ridges of controlled depth Correct answer.

Explanation

A notched trowel spreads adhesive in ridges of a depth set by the notch size. When tile is pressed into the ridges, the mortar collapses to fill the coverage area. Grout removal, substrate leveling, and scoring are done with other tools.

Question 33Tile Craft Fundamentals and Safety

Why should a tile setter keep the work area clear of standing water and slurry?

  1. To keep the tile from absorbing water
  2. To reduce the amount of grout needed
  3. To speed up the curing of thin-set
  4. To prevent slips and falls on the jobsite Correct answer.

Explanation

Wet saws and mixing produce water and slurry that make floors slippery. Cleaning as you go and keeping walkways dry prevents slip-and-fall injuries, which are a leading cause of jobsite accidents. The other options do not describe a safety reason for housekeeping.

Question 34Tile Craft Fundamentals and Safety

A setter is about to spread thin-set on a concrete floor that has a dusty film. What is the correct action?

  1. Vacuum and damp-wipe the slab, then let it dry before spreading Correct answer.
  2. Spread the thin-set directly over the dust
  3. Seal the dust into the slab with a coat of grout
  4. Prime the dust with water and tile immediately

Explanation

Dust and loose material prevent the thin-set from bonding to the concrete. Vacuuming and damp-wiping removes the film, and letting the surface dry avoids diluting the mortar. Bonding over dust leads to debonding and hollow spots.

Question 35Tile Craft Fundamentals and Safety

A worker is mixing thin-set and adds extra water after the mortar begins to stiffen. What is the likely result?

  1. The open time of the mortar is reduced
  2. The mortar loses strength and may fail to bond Correct answer.
  3. The mortar gains strength and cures faster
  4. The pot life of the mortar is extended

Explanation

Adding water to mortar that has already begun to set disrupts the chemical reaction and weakens the cured material. Mortar past its pot life should be discarded. Extra water does not extend pot life or improve performance.

Question 36Tile Craft Fundamentals and Safety

A setter must install tile on a wall over a cementitious backer board. Which fastener schedule is appropriate?

  1. Nails driven only at the corners of each board
  2. Fasteners spaced at every 24 inches on center
  3. Corrosion-resistant screws into framing at the manufacturer's specified spacing Correct answer.
  4. Adhesive alone without mechanical fasteners

Explanation

Backer board must be fastened with corrosion-resistant screws into the framing at the spacing the manufacturer specifies, often 6 to 8 inches on center. Fastening only at corners or at wide spacing leaves the board loose. Adhesive alone is not an approved attachment method.

Question 37Tile Craft Fundamentals and Safety

A setter is installing tile over a wood-framed floor and wants to reduce deflection. Which action is most appropriate?

  1. Verify the floor meets the required deflection limit and add blocking or stiffening as needed Correct answer.
  2. Increase the grout joint width to hide movement
  3. Install tile directly over the subfloor with mastic
  4. Use a thinner layer of thin-set to reduce weight

Explanation

Wood floors must meet a deflection limit, commonly L/360 for ceramic tile, before tile is installed. Adding blocking or stiffening the joists corrects excessive deflection. Mastic over bare subfloor, wider joints, or thinner mortar do not solve structural movement.

Question 38Tile Craft Fundamentals and Safety

What is the correct way to handle a wet saw blade that is worn or chipped?

  1. Replace it before continuing the cut Correct answer.
  2. Increase the water flow to compensate
  3. Continue cutting until the blade fails
  4. Turn the blade around and keep cutting

Explanation

A worn or chipped diamond blade cuts poorly and can shatter or grab the tile, creating a kickback hazard. The blade should be replaced before work continues. Reversing it or adding water does not restore a damaged blade.

Question 39Tile Craft Fundamentals and Safety

A setter is choosing between a latex-portland cement mortar and an epoxy mortar for a commercial kitchen floor. Which factor most strongly favors epoxy mortar?

  1. Resistance to chemicals and harsh cleaning Correct answer.
  2. Easier cleanup with water
  3. Lower material cost
  4. Longer open time for large areas

Explanation

Epoxy mortar provides high chemical resistance and withstands harsh cleaning, which suits commercial kitchens. It costs more, requires careful mixing, and is cleaned with special solvents rather than water. Open time is generally shorter, not longer.

Question 40Tile Craft Fundamentals and Safety

A helper is told to "key in" the thin-set before combing it. What does this mean?

  1. Pressing mortar firmly into the substrate with the flat side of the trowel Correct answer.
  2. Removing excess mortar from the trowel
  3. Mixing mortar with a key-shaped paddle
  4. Adding a second layer of mortar over the first

Explanation

Keying in means using the flat side of the trowel to force mortar into the pores and texture of the substrate. This improves mechanical bond before the notched side is used to comb ridges. It is not a second layer, a removal step, or a mixing method.

Question 41Tile Craft Fundamentals and Safety

Which practice best prevents grout from drying too quickly in a hot, dry room?

  1. Applying grout in very thin sections
  2. Grouting in direct sunlight with fans running
  3. Dampening the tile and controlling airflow during grouting Correct answer.
  4. Adding more water to the grout mix

Explanation

Grout that dries too fast can crack and powder. Dampening the tile and limiting airflow or direct sun slows evaporation so the grout cures properly. Adding extra water weakens grout, and fans or sun accelerate the problem.

Question 42Tile Craft Fundamentals and Safety

A setter is installing large-format tile on a wall and needs to prevent sagging. Which approach is best?

  1. Apply a thinner coat to reduce weight
  2. Install from the top down without spacers
  3. Use extra water in the mix to make it flow
  4. Use a non-sag thin-set rated for large-format wall tile Correct answer.

Explanation

Non-sag mortars are formulated to hold heavy tile in place on vertical surfaces. Adding water or thinning the coat reduces bond and does not stop sag. Working top-down without spacers gives no control over alignment.

Question 43Tile Craft Fundamentals and Safety

Why must a tile setter wait for thin-set to cure before grouting?

  1. Grouting too soon can dislodge tile and weaken the bond Correct answer.
  2. Thin-set needs water from the grout to cure
  3. Grout joints will be too wide if grouted early
  4. Grout will not stick to cured thin-set

Explanation

Walking on and grouting tile before the thin-set cures can break the bond and move the tile. The mortar needs time to develop strength. Grout does not supply curing water, and joint width is set by spacers, not grout timing.

Question 44Tile Craft Fundamentals and Safety

A crew is working in a confined bathroom with a propane heater in winter. Which concern is most serious?

  1. Increased grout color variation
  2. Carbon monoxide buildup and oxygen depletion Correct answer.
  3. Excess humidity damaging the tile
  4. Faster curing of the thin-set

Explanation

Fuel-burning heaters in a confined space produce carbon monoxide and consume oxygen. Ventilation and CO monitoring are required to protect workers. Humidity, curing speed, and grout color are not the primary safety issue.

Question 45Tile Craft Fundamentals and Safety

Which statement best describes the purpose of a movement joint in a large tile field?

  1. It replaces the need for a substrate
  2. It accommodates expansion and contraction of the tile assembly Correct answer.
  3. It allows grout to be applied faster
  4. It hides cutting errors in the field

Explanation

Movement joints divide large tile fields so expansion and contraction do not cause tenting or cracking. They are placed at intervals specified by standards and design. They are not a way to hide errors or speed grouting.

Question 46Tile Craft Fundamentals and Safety

A setter is installing tile in a wet area and must choose a waterproofing method. Which approach is correct?

  1. Apply a bonded waterproof membrane over the substrate before tiling Correct answer.
  2. Rely on grout and tile alone to keep water out
  3. Seal only the grout lines after installation
  4. Use mastic as the waterproofing layer

Explanation

Tile and grout are not waterproof. A bonded waterproof membrane applied over the substrate protects the assembly from moisture. Relying on grout, sealer, or mastic does not provide reliable waterproofing.

Question 47Tile Craft Fundamentals and Safety

A tile floor shows lippage at several joints after installation. Which cause is most likely?

  1. Variation in tile thickness or an uneven substrate Correct answer.
  2. Grout mixed with too much water
  3. Missing movement joints at the perimeter
  4. Use of a notched trowel

Explanation

Lippage is an unevenness between adjacent tile edges. It usually results from tile thickness variation, an uneven substrate, or improper mortar thickness. Grout mix, movement joints, and normal trowel use do not directly cause lippage.

Question 48Tile Craft Fundamentals and Safety

Why does industry guidance limit the use of organic adhesive (mastic) in wet areas?

  1. Mastic cannot be applied with a notched trowel
  2. Mastic cures too slowly for wall tile
  3. Mastic is too strong for backer board
  4. Mastic can re-emulsify and lose bond when exposed to moisture Correct answer.

Explanation

Organic adhesive can soften and lose bond when repeatedly exposed to moisture, so it is restricted in showers and other wet areas. It cures reasonably fast on walls and is applied with a notched trowel. Strength on backer board is not the concern.

Question 49Tile Craft Fundamentals and Safety

A setter is installing tile over a newly poured concrete slab that has not fully cured. What is the best course of action?

  1. Wait for the slab to cure as required and test for moisture before tiling Correct answer.
  2. Use mastic to isolate the tile from moisture
  3. Apply a sealer and tile the same day
  4. Tile immediately to save time

Explanation

Green concrete releases moisture that can debond tile and damage the assembly. The slab must cure for the required period, and moisture testing should confirm it is ready. Tiling immediately, sealing, or using mastic does not solve the moisture problem.

Question 50Tile Craft Fundamentals and Safety

A crew must cut tile in an occupied building. Which control best reduces dust and noise impact on occupants?

  1. Use a wet saw or dust-collecting cutter in a contained area Correct answer.
  2. Cut tile in the main hallway for convenience
  3. Run dry grinders without collection to save time
  4. Open windows and cut anywhere in the building

Explanation

Wet cutting or dust collection at the source controls silica dust, and containing the work area limits noise and dust spread. Cutting in hallways or running dry grinders without collection exposes occupants and workers. Opening windows alone does not control the hazard.