Regrout a Shower

Grout fails in predictable ways. It cracks along stress lines, crumbles where water sits longest, and turns dark where mildew takes hold. Most shower grout reaches end-of-life around the seven-year mark, though poor ventilation or hard water can cut that in half. When grout lines look more like canals than seams, regrouting stops being optional. A proper regrout job takes a weekend and costs less than a plumber's service call. The work itself is straightforward—remove the old material, pack in the new, wipe clean. The trick is in the removal phase, where patience matters more than strength, and in the curing phase, where discipline beats speed. Done right, new grout transforms a dingy shower into something that looks freshly tiled, and it buys you another decade of reliable service.

1. Cut Out Old Grout Carefully. Use a grout saw to cut out old grout to a depth of at least 1/8 inch, ideally 1/4 inch. Work slowly and deliberately to avoid chipping tile edges. Focus on vertical joints first, then horizontals. Vacuum out debris frequently so you can see your progress and catch any tile damage early.
2. Dry Every Last Crevice. Vacuum all dust from grout channels, then scrub joints with a stiff brush and water. Wipe down tile faces with a damp sponge to remove any remaining dust. Let everything dry for at least two hours—longer if your bathroom runs humid. Run a fan or open windows to speed the process.
3. Hit Toothpaste Consistency. Combine grout powder and water according to package directions, usually about 3 parts powder to 1 part water. Mix thoroughly, let it slake for 10 minutes, then remix. The consistency should match thick toothpaste—stiff enough to pack into joints but workable enough to spread smoothly.
4. Pack Deep, Scrape Clean. Load grout onto a rubber float and press it firmly into joints at a 45-degree angle. Work diagonally across tiles to pack grout deep into channels. Make two passes over each section—first to fill, second to compress. Scrape excess grout off tile faces as you go.
5. Wring Sponge Nearly Dry. Wait 15 to 20 minutes after grouting, then wipe tile faces with a damp sponge in circular motions. Rinse the sponge frequently in clean water and wring it nearly dry. Remove surface grout without digging into joints. Work in small sections and change your water when it gets cloudy.
6. Buff and Shape Joints. After another hour, buff away grout haze with a clean, dry microfiber cloth. Check grout lines and use a fingertip wrapped in damp paper towel to smooth any uneven spots. Shape joints to a slight concave profile if needed. Let cure undisturbed for 24 hours minimum before light water exposure.
7. Seal Every Grout Line. Wait 72 hours for complete curing, then apply grout sealer with a small brush or applicator bottle. Work carefully to coat grout lines without getting sealer on tile faces. Wipe any overspray immediately. Let sealer dry for the time specified on the bottle, usually 2 to 4 hours.
8. Ease Back Into Use. Avoid heavy water exposure for 24 hours after sealing. Use the shower lightly if needed, but skip long hot showers for the first week. Apply a second coat of sealer after 48 hours for high-traffic showers. Resume normal use after the second seal cures.