How do I replace a cracked tile?

To replace a cracked tile, cut out the grout around it, break the tile out, scrape the old mortar flat, set a matching spare in fresh thin-set and grout it once the mortar has cured. Daltile calls replacing a broken tile rather simple, and stresses protective gear, especially goggles.^[1] Its three-part method is to remove the grout around the broken tile, carefully remove the tile with a hammer and chisel, then remove the hard mortar or adhesive that was underneath.^[1] The steps above fill in the details.

First, look at why it cracked

A single tile with a chip or a starburst crack where something heavy was dropped is usually just a broken tile. Replace it and you are done.

A crack that runs in a line across two or more tiles, a tile that sounds hollow when you tap it, or a floor that flexes when you walk on it is a different problem. Floors and walls shift over time, causing cracks beneath the finished tile.^[5] A new tile laid over the same movement will usually crack again. See why floor tiles crack before you start, and how to keep tile from cracking for what fixes the cause.

Get a matching tile before you break anything

The new tile is the hardest part to find, so find it first. Daltile recommends buying about 10% more tile than a job needs and keeping it as "attic stock"^[1] so a repair can use tile from the same dye lot and printing process, which can change slightly over the years.^[1] Check the garage, basement and attic for a leftover box. If there is none, take a broken piece to a tile shop and compare size, thickness, colour and surface finish side by side.

What you need

• A grout saw, or an oscillating multi-tool with a grout-removal blade
• A hammer, a cold chisel or a stiff putty knife, and a shop vacuum
• Thin-set mortar suited to your tile, a small notched trowel and a mixing bucket
• Grout in the matching colour, a rubber grout float, a sponge and a bucket of clean water
• Safety glasses or goggles, gloves and a particulate respirator

Choosing the grout. Match the type to the joint width. Polyblend Plus Sanded Grout is made for joints 1/8 to 1/2 inch wide, and the maker says its non-sanded version may suit joints up to 1/8 inch.^[3] Its data sheet also warns that some ceramic, glass, metal, marble or stone tiles can be scratched by the sand in sanded grout,^[3] so test a corner first on polished or glass tile.

Matching the colour. Daltile notes that grout colour can vary slightly from batch to batch and can darken over time,^[1] so new grout beside old often looks lighter at first. It also says a grout stain can correct a colour that does not come out as expected.^[1] If the old grout is badly stained, cleaning the whole floor first makes the match easier to judge.

Work safely with dust and cement

Cutting tile can produce silica dust, which can be hazardous if inhaled.^[1] Daltile does not recommend dry cutting, recommends wet cutting, and recommends a properly fitted NIOSH/MSHA approved particulate respirator when cutting tile or removing installed tile.^[1] OSHA explains that respirable crystalline silica is created by cutting, sawing, grinding and drilling materials such as stone, concrete and mortar,^[6] and that workers who breathe it are at increased risk of silicosis, an incurable lung disease.^[6] For one tile, keep the dust down with a vacuum held at the work and a damp sponge, and wear the respirator anyway.

Cement grout is caustic too. For its grout, the data sheet calls for impervious gloves such as nitrile, safety glasses and a NIOSH N95 respirator,^[3] and warns that cement grout can cause severe skin burns and serious eye damage.^[3]

This guide is for ceramic, porcelain and stone tile. Old resilient flooring is another matter: vinyl floor tiles and the backing and adhesives of vinyl sheet flooring are among the building materials that have contained asbestos.^[7] EPA says you can't tell whether a material contains asbestos simply by looking at it, unless it is labeled.^[8] "If in doubt, treat the material as if it contains asbestos and leave it alone."^[8]

Tips that make the repair disappear

• Protect the neighbours. Put painter's tape on the edges of the surrounding tiles before you cut the grout. Most chipped edges happen when a grout saw jumps out of the joint.
• Break from the middle. Starting in the centre of the cracked tile and working outward takes pressure off the tiles around it.
• Get the height right. Scrape the old bed lower than you think you need. A tile that sits proud of its neighbours is a trip edge and catches light.
• Mix grout to the bag's ratio. Custom's data sheet says do not add water as it stiffens, because extra water can weaken the grout and cause colour variation, shrinkage, cracks and pinholes.^[3]
• Use a fast-setting mortar to finish in a day. Ordinary thin-set wants about a day before grouting, but a fast-setting repair mortar such as Custom's Tile Repair Professional Thin-Set can be grouted in 2 hours and walked on in 4.^[4]
• Respect the cure. Custom's data sheet for Polyblend Plus says not to open it to foot traffic before it has cured for 16 hours.^[3] Put a box or a chair over the tile so nobody steps on it.

Wall tile and showers

The same method works on a backsplash or a dry wall. In a shower or tub surround, go gently with the chisel: the backer board or membrane behind the tile is what keeps water out of the wall. If what you find behind a broken shower tile is soft, dark or wet, stop there. Caulked joints, such as the one where tile meets the tub, are a separate job; see how to recaulk a bathtub.

Stop and call a pro if

• Cracks run across several tiles in a line, or the floor bounces, dips or creaks where the tiles crack. That is a subfloor or structure question.
• More tiles sound hollow when tapped than the one you meant to replace.
• The board behind a wall or shower tile is soft, crumbling or wet, or there is a stain on the ceiling below.
• The tile is natural stone, a large-format porcelain plank, or part of a pattern you cannot match.
• The floor is old vinyl or sits on old black adhesive, and you do not know what it is made of.

If it is more than you want to take on, compare hiring a handyman or a tile installer and what a few tiles cost to replace in Virginia. You can also browse small tile jobs, find handyman businesses around Blacksburg, or read the other handyman answers.

When you are ready, describe the tile repair once and local businesses quote it.