How to regrout tile
Cracked, crumbling or missing grout won't come back with cleaning; the tile needs to be regrouted. That means cutting out the old grout, packing in new grout and cleaning the tile before it hardens. It's slow, careful work but needs only basic tools. Do it before water gets behind the tile, because loose tiles and rotted backing are much bigger repairs. Regrouting is slow, but it's not hard. Most of the work is getting the old grout out.
What grout does
Grout fills the joints between tiles to lock them in place and keep dirt and most water out. Regular cement grout is porous, so it holds moisture and stains unless it's sealed. Over time, movement, harsh cleaners and water wear it down until it cracks or falls out in pieces.
There are three main types. Sanded cement grout has fine sand added for strength and is used for joints wider than 1/8 inch. Unsanded grout is smoother and used for narrow joints of 1/8 inch or less, and on polished stone that sand could scratch. Premixed grouts, often urethane or acrylic based, come ready to use and usually don't need sealing, but they can be less forgiving to work with.
Why grout fails
Grout cracks as the house shifts and settles.
Moisture and acidic or abrasive cleaners erode grout.
Unsanded grout in wide joints shrinks and cracks.
Change-of-plane joints move and crack grout.
| You notice | Likely cause | Start at |
|---|---|---|
| Grout cracked or crumbling | Worn grout | Step 1 |
| New grout won't stick | Dust or residue in joints | Step 2 |
| Not sure which grout to buy | Joint width decides | Step 3 |
| Grout lumpy or runny | Mixing ratio | Step 4 |
| Pinholes or gaps in new grout | Joints not packed fully | Step 5 |
| Cloudy film on tile | Grout haze | Step 7 |
| Grout cracks in corners | Should be caulk | Step 8 |
Let's fix it
- Remove the old groutPut on a dust mask and safety glasses. Run a grout saw back and forth along each joint, or use an oscillating tool with a grout blade at low speed, keeping the blade centered so it doesn't chip the tile edges. Remove at least two-thirds of the grout's depth, and never less than about 1/8 inch, so the new grout has room to bond. Work slowly near corners and fixtures, and switch to a hand saw where the power tool is hard to control.
- Clean out the jointsVacuum all the dust and loose bits out of the joints with a shop vacuum. Wipe the tile and joints with a damp sponge and let them dry. Old grout dust or soap scum left in the joints will keep the new grout from sticking.
- Choose the right groutMeasure the joint width. Use sanded grout for joints wider than 1/8 inch and unsanded grout for narrower joints or polished stone and glass tile that sand could scratch. A premixed urethane or acrylic grout is an option if you want something that resists stains without sealing. Buy a color to match the existing grout, or plan to regrout the whole area so it all matches.
- Mix the groutFor powdered grout, add the powder to the amount of water on the bag, a little at a time, and mix to a smooth, peanut-butter consistency. Let it rest for the time listed on the bag, often about 10 minutes, then remix briefly without adding more water. Mix only what you can use in about 20–30 minutes.
- Pack the jointsScoop grout onto the tile and hold the rubber float at about a 45-degree angle. Push the grout diagonally across the joints, pressing firmly so it fills them completely. Then hold the float nearly upright and scrape off the extra, again working diagonally so you don't drag grout out of the joints. Work in small sections of a few square feet.
- Wipe the tileWait until the grout firms up a bit, usually 15–30 minutes depending on the product. Wring out a grout sponge so it's barely damp and wipe diagonally across the tile in light passes, rinsing the sponge often. Shape the joints so they're smooth and slightly below the tile edge. Too much water weakens the grout and washes it out of the joints.
- Buff off the haze and let it cureAfter the grout has set for the time on the package, a light film called haze will appear on the tile. Buff it off with a dry microfiber cloth. Keep the area dry for the cure time listed, often 24–72 hours before showering.
- Seal and caulkOnce cement grout has cured as directed, often 2–3 days, brush on a penetrating grout sealer and wipe off any that gets on the tile. Where walls meet each other or the tub, use flexible caulk rather than grout, since those change-of-plane joints move and grout there cracks.
Watch it done
- Joints are full and smooth
- No haze on the tile
- No cracks after a few weeks
If it's not a grout problem
If the grout is solid but just stained or dingy, cleaning may be all it needs. See the guide for cleaning grout.
If the joint around the tub or shower pan is the problem, check our guide for recaulking a tub.
What a pro typically charges (a rough estimate; prices vary by area): A tile pro typically charges $5–$15 per square foot to regrout, or about $400–$1,200 for a typical tub surround and $300–$800 for a small bathroom floor. Expect more if tiles need replacing.
Find a plumber near youSomething else going on?
Regrouting questions
Can you regrout over old grout?
Not well. Remove at least part of the old grout so the new grout has room to bond.
Should I use sanded or unsanded grout?
Sanded for joints wider than 1/8 inch, unsanded for narrower joints or polished stone and glass tile that sand could scratch.
How long before I can shower after regrouting?
Often 24–72 hours, depending on the grout. Check the package.
Should I grout or caulk shower corners?
Caulk. Corners and tub joints move, and grout there cracks.
Can I replace grout myself?
Yes. It's slow, careful work but needs only basic tools: cut out the old grout, pack in new grout and clean the tile before it hardens.