How to Remove Old Grout and Regrout Tile Lines

Grout fails. It cracks, stains, holds water, and eventually lets moisture creep behind your tile where it causes real damage. The good news: regrouting is entirely doable without removing tile, and it'll make your bathroom or kitchen backsplash look new again. The key is committing to getting the old grout completely out—half-measures leave voids that trap water and fail again in months. This is methodical work, not complicated work. Give yourself a full day or weekend depending on your tile area, work methodically in sections, and you'll have grout lines that'll last another decade.

1. Know Your Battlefield. Walk the entire tiled area and identify where grout is cracked, discolored, or soft. Press it with a thumbnail—if it crumbles easily, it's ready to go. Lay out your grout saw or oscillating multi-tool with grout blade, shop vacuum, old towels, and a bucket of warm water. If you're doing a large area (shower walls, entire backsplash), break the job into sections so you're not working on wet grout and dried-out sections simultaneously.
2. Cut Out the Old. Start at a corner or inconspicuous spot. Hold the grout saw at a shallow angle and work it back and forth along one grout line, letting the blade do the work—don't force it. The goal is to cut out the top 50–75 percent of the grout depth. You don't need to get every last bit, but you want to remove enough that new grout can lock in. Work in 2–3 foot sections. If you hit a spot that's particularly hard, switch directions or angle slightly; some old grout was mixed to last and will require patience.
3. Eliminate Every Speck. Once a section of grout lines is cut, switch to your shop vacuum immediately. Use the hose with a crevice attachment and go over every grout line multiple times. You're looking for a clean, dry line with no powder or dust sitting in it. Wipe your fingers along the grout lines—if they come away white or gray, vacuum again. This step determines whether your new grout bonds properly. Don't skip it or rush it.
4. Bone-Dry Wins. Use a damp sponge or cloth to wipe out all the grout lines again, then inspect with a flashlight. Any remaining dust or debris will cause bonding problems. Let the tile dry for at least 2–4 hours depending on humidity and tile type. Porous tile like natural stone may need longer. If you're working in a bathroom, crack a window or run a fan to speed drying. You should be able to touch the grout line and feel no moisture.
5. Get The Consistency Right. Pour unsanded grout (for lines under 1/8 inch wide) or sanded grout (for wider lines) into a bucket. Add water gradually while mixing with a margin trowel or grout paddle. The goal is a consistency like peanut butter—thick enough to hold a ridge, wet enough to work into lines without tearing. Mix only as much as you can use in 20–30 minutes; grout starts to set and becomes unusable. If it starts to stiffen, add a little water and remix rather than starting over.
6. Pack It Deep. Load grout onto a grout float (a trowel with a rubber or foam face). Press the loaded float into the grout lines at a 45-degree angle, using firm pressure to pack grout deep into the line. Work diagonally across the tile—not parallel or perpendicular to the lines. This angle helps the float cut into multiple grout lines at once rather than dragging out grout you just packed in. Fill lines completely, overfilling slightly so they're crowned.
7. Smooth Like Butter. Wait 10–20 minutes for the grout to firm up enough that it doesn't pull out of the lines when you touch it. The timing depends on humidity and grout type—test a line gently with your finger. Once it's set enough, use a damp sponge or grout sponge and wipe diagonally across the tiles, rinsing the sponge frequently in clean water. Use light pressure and change direction (work from different angles) so you don't drag grout out of the lines. The goal is flat, smooth lines flush with the tile surface.
8. Check Your Work. After 24 hours, grout will be fully cured. A thin haze of grout dust may remain on the tile surface. Use a dry cloth or an old t-shirt to buff the tiles and remove this haze. Check for any voids or thin spots in the grout lines and mark them. Small voids can be touched up with a grout pen or by mixing a small batch of the same grout and carefully pressing it into the gap.
9. Lock In The Win. Wait at least 72 hours for grout to fully cure before sealing. Porous grout in kitchens or bathrooms benefits from sealing to prevent staining and water absorption. Apply grout sealer with a small brush, following the product instructions. Most sealers dry clear and require no maintenance. Sealing is optional for non-porous tile like glazed ceramic but recommended for natural stone, matte tile, or any grout in wet areas.
10. Stay Ahead Forever. Keep grout clean by wiping spills immediately and using a pH-neutral cleaner for routine maintenance. Avoid harsh bleach-based products that can break down grout over time. Reseal every 1–2 years in wet areas. If you notice new cracks appearing after a month or two, they may indicate movement in the substrate or poor adhesion—photograph them and consider whether the original tile was properly set before assuming it's a grout problem.