How to Regrout Tile: Remove Old Grout and Apply Fresh Grout in a Weekend

Frequently Asked Questions

How do I know if my grout needs to be replaced versus just cleaned?

Grout that is discolored, yellowed, or stained can often be restored with a grout cleaner or grout whitener — you don't necessarily need to remove and replace it. Grout that is crumbling, cracking, missing in sections, or has visible gaps is structurally compromised and should be removed and replaced. Grout with black mold that doesn't respond to bleach cleaning should also be removed, as the mold may have penetrated the grout body. Hazing or chalky surface appearance is usually surface-level and responds to cleaning.

Do I need to remove all the old grout or just the surface?

New grout bonds poorly to old grout. For a durable result, remove the old grout to a depth of at least 1/8 inch — ideally 2/3 of the grout joint depth. Shallower removal leads to thin new grout that cracks and flakes within a year. You don't need to remove every trace of the old grout down to the substrate, but you need enough depth for the new grout to bond and cure without cracking.

What is the difference between sanded and unsanded grout?

Sanded grout contains fine sand aggregate and is used for joints wider than 1/8 inch. The sand gives it body and prevents shrinkage cracking in wider joints. Unsanded grout (also called non-sanded or wall grout) is smooth and is used for joints 1/8 inch or narrower — it's also preferred for polished stone tile where sand particles could scratch the surface. Using the wrong type causes problems: sanded grout in narrow joints won't fit; unsanded grout in wide joints will crack as it dries and shrinks.

How do I match new grout to my existing grout color?

Grout color always shifts slightly after curing — fresh grout is lighter when wet and darkens as it cures. Colors also shift with age, exposure to cleaning products, and mineral staining. To match: chip a small piece of old grout from a hidden area and bring it to the tile store to compare against color cards. Get a small sample and let it dry completely before committing to a bag — wet grout color is not reliable. If an exact match isn't possible, replace the grout throughout the entire visible surface so everything looks consistent.

Can I grout over existing grout without removing it?

For very thin joints with intact (not crumbling) grout where you just want a color refresh, a grout colorant or grout paint is a better approach than grouting over. True grouting over existing grout works only if the old grout is at least 1/4 inch below the tile surface (very deep joint). In most cases — standard 1/16 to 3/16-inch joints — grouting over adds a layer too thin to be durable. Remove the old grout for any lasting result.

How long does regrouted tile need to cure before getting wet?

Standard cement-based grout needs 24–72 hours before light water exposure and 7 days before full curing. Avoid wet cleaning the grout surface for 24 hours after application, and avoid soaking or heavy water exposure (shower use) for at least 72 hours. Epoxy grout cures faster — typically 24 hours to full use — but is much harder to apply and costs significantly more. After full cure (7 days for cement grout), apply grout sealer to protect the surface.

Regrouting tile: (1) Remove all old grout — use an oscillating tool with grout blade or a manual grout saw to remove at least 1/8 inch deep. (2) Clean the joints with a vacuum and damp cloth; let dry completely.

Crumbling, discolored, or cracked grout is one of the most common bathroom problems — and one of the most satisfying DIY fixes. Regrouting doesn’t require tile experience, and the result looks as good as new tile. The hardest part is the grout removal, which is tedious but straightforward. Plan on a full weekend: one day for removal and prep, one day for grouting and cleanup.

What You Need

The total material cost for a typical bathroom floor or shower stall is $30–$80 depending on the size and the grout type you choose.

• Oscillating tool with grout removal blade ($30–$80 for a basic oscillating tool; $10–$20 for a replacement grout blade)
• Manual grout saw ($8–$15 for corners and edges where the oscillating tool can’t reach)
• Sanded or unsanded tile grout ($10–$25 per 10-lb bag — enough for a standard bathroom floor or shower)
• Grout float ($8–$15 for a rubber-faced grout float)
• Grout sealer ($10–$20 for a spray-on penetrating sealer)
• Shop vacuum with fine dust filter ($40–$80 if you don’t own one — essential for cleanup after grout removal)
• Bucket, margin trowel, large sponge, and clean water

Knee pads if you’re working on a floor — grout removal on hands and knees for several hours without them is painful.

Understanding Grout Types and When to Use Each

Before buying grout, confirm the joint width and tile type. This determines which grout you need.

Sanded grout: Use for joints 1/8 inch and wider. Most floor tile, standard wall tile with typical spacing, and most shower tile uses sanded grout. It’s the most common type and comes in the widest color range.

Unsanded grout: Use for joints narrower than 1/8 inch. Also use for polished natural stone tile (marble, travertine, limestone) where the sand in sanded grout would scratch the tile surface during application.

Epoxy grout: A two-part system that is extremely stain and chemical resistant. Used in commercial kitchens and high-traffic wet areas. Expensive ($50–$80 for a small kit), difficult to work with (must be applied quickly before it sets), and overkill for most residential applications. Not recommended for first-time regrouters.

Color: Take a sample of old grout to the store. Most manufacturers (Mapei, Custom Building Products, TEC, Laticrete) offer 30–50 colors. The sample card colors are photographed wet — actual cured color is lighter. Ask the store for a dry swatch if possible.

Step 1: Prepare the Work Area

Remove everything from the tiled surface — rugs, bath mats, toiletries, soap dishes. For a shower regroup, tape plastic sheeting over the drain to keep grout particles out of the drain line.

Clean the tile surface thoroughly with a tile cleaner or bathroom spray cleaner. Grout removal generates a lot of fine dust — a clean starting surface means you can see the joint lines clearly.

Put on safety glasses and a dust mask (N95 minimum). Grout removal with an oscillating tool generates very fine silica dust, which is a respiratory hazard. Ventilate the room by opening windows and running the bathroom exhaust fan.

Step 2: Remove the Old Grout

Grout removal is the most time-consuming step. Budget 2–4 hours for a standard shower stall, 1–2 hours for a bathroom floor.

With an oscillating tool: Fit the grout removal blade (a thin, U-shaped or narrow carbide blade) into the oscillating tool. Hold the tool at a low angle to the tile surface and run it along the grout joint. The blade vibrates rapidly to cut through the grout without (in theory) chipping the tile. Apply light, consistent pressure — the tool does the work. Pressing hard into a single spot can chip the tile edge.

Work in straight passes from one side of the joint to the other. Make 2–3 passes down each joint until you’ve reached a depth of at least 1/8 inch. You can check depth by dragging a grout saw manually along the joint — you’ll feel the resistance decrease when you’ve removed enough.

With a manual grout saw: Use this for the corner joints, the joint between the tile and tub/shower, and any area where the oscillating tool can’t safely operate without hitting adjacent tile. A manual grout saw requires more elbow grease but gives better control.

Technique tip: Work horizontal joints first, then vertical joints. In corners, make a single careful pass with the manual saw to clean out the corner without scratching the adjacent tile.

After removal: Vacuum all dust and debris from the joints using the shop vac with the fine dust filter. Blow out corners with compressed air if available. The joints must be completely free of loose debris before grouting — any loose material under the new grout creates a weak spot.

Wipe the tile surface clean with a damp sponge. Inspect every joint: they should be clean, uniform depth, with no loose chips of old grout. Tap along the tile edges — any loose tiles should be re-adhered with fresh thinset before grouting.

Step 3: Mix the Grout

Pour approximately 6–8 ounces of clean water into a clean bucket. Add grout powder to the water (not water to powder) while stirring with a margin trowel or mixing paddle. The consistency you’re aiming for is peanut butter — thick enough that it holds a shape when you pull the trowel through it, but pliable enough to pack into joints.

Let the mixed grout slake (rest) for 5–10 minutes after initial mixing. Then stir again. This hydration step activates the cement binders and produces a smoother, more workable grout. Don’t add more water after slaking — this weakens the grout.

Mix only as much grout as you can apply in 20–30 minutes. Most grout has a working time of 20–45 minutes before it stiffens enough to be difficult to work with. For a full shower, mix in batches.

Cost note: A 10-lb bag of grout is enough for approximately 50 square feet of 4x4 tile with 3/16-inch joints, or approximately 100 square feet of 12x12 tile with 1/8-inch joints. Calculate your area before buying.

Step 4: Apply the Grout

Work in sections of 10–15 square feet at a time. Scoop grout onto the tile surface and spread it with the grout float held at a 45-degree angle to the tile surface. Push the grout firmly into the joints — press the float diagonally across the joint lines, not parallel to them. Diagonal motion packs grout fully into the joint without pulling it back out.

After packing the joints in a section, use the float edge to sweep excess grout off the tile surface. Hold the float nearly vertical (almost perpendicular to the tile) and use it like a squeegee to remove surface grout. Work diagonally to the joint lines to avoid pulling grout out of the fresh joints.

Don’t try to get the tile perfectly clean at this stage — you’re just removing the bulk of the excess. Some grout haze will remain and you’ll clean it later.

Inspect each joint after floating. Any joint that’s low (not filled flush with the tile surface) or has a void: reapply grout and re-float. Grout shrinks slightly as it cures, but an obviously low joint during application will be noticeably below the tile surface when dry.

Step 5: Clean the Tile Surface

Wait 15–20 minutes after applying grout to a section before beginning the sponge cleanup — this allows the grout in the joints to firm up slightly so sponge cleaning doesn’t pull it back out.

Wring a large sponge in clean water until barely damp. Wipe the tile surface with the sponge in a circular motion, then a diagonal pass to avoid disturbing the joints. Rinse the sponge frequently in clean water — a dirty sponge smears grout rather than removing it.

Change the water in your bucket frequently. Cloudy water has suspended grout particles that deposit back onto the tile as you clean. Fresh, clean water for each rinse makes a significant difference in how clean the tile looks after drying.

The goal is to clean the tile surface while leaving the joint grout level with — or very slightly below — the tile surface. The grout joint does not need to be perfectly smooth at this stage; minor ridges from the float will harden and can be buffed off later.

Grout haze: After the grout dries fully (24–48 hours), a white haze often remains on the tile surface. This is normal. Buff it off with a dry terry cloth rag in a circular motion. For heavier haze, a commercial grout haze remover ($10–$15) dissolves dried grout residue without damaging the tile. Do not use acid-based haze removers on natural stone — use pH-neutral cleaners.

Step 6: Caulk the Corners and Transitions

Grout is not the right material for the joint between tile and a dissimilar surface (tub edge, shower floor, countertop edge, wall corner joints). These areas are transition points where different materials move at different rates when temperature changes. Grout in these joints will crack and separate within a few months.

After grouting, these joints should be filled with flexible silicone or sanded acrylic caulk that matches the grout color. Apply caulk to:

• The joint between the tile and the tub or shower pan edge
• Inside corner joints (vertical corners in showers)
• The joint between tile and any countertop or window sill
• Anywhere tile meets the floor

Apply caulk in a continuous bead, then smooth it with a wet fingertip or a caulk finishing tool. Wipe excess with a damp cloth before it skins over.

Step 7: Seal the Grout

After the grout has cured for the manufacturer’s recommended time (usually 48–72 hours minimum, 7 days for full cure), apply grout sealer to all grout joints.

Penetrating grout sealer soaks into the grout body and makes it resistant to staining, moisture penetration, and mold growth. It does not change the appearance of the grout and lasts 1–3 years before reapplication is needed.

Apply sealer with a small brush directly onto the grout joints, or use a spray bottle for large floor areas. Let it penetrate for 10 minutes, then wipe excess off the tile surface with a clean cloth. Apply a second coat for shower grout and any grout in wet areas.

Annual maintenance: Reseal grout joints once per year in showers and every 2–3 years on floors. A 5-minute annual sealer application is all it takes to prevent the discoloration and water damage that leads to full regrouting.

Cost Summary

Task	DIY Cost	Pro Cost
Shower stall regrout (3 walls)	$40–$80	$400–$800
Bathroom floor regrout (50 sq ft)	$30–$60	$300–$600
Grout sealer (annual)	$10–$20	$75–$150

The labor savings on a professional regrouting job make this one of the highest-value DIY projects in a bathroom renovation.

Related Reading

• How to Fix a Cracked Tile
• How to Install a Tile Backsplash
• Bathroom Remodel Cost Breakdown
• How to Fix a Floor Tile That Is Loose — reattach hollow tiles before regrouting so the new grout doesn’t crack