Repair cracked tile grout
Remove failed grout from stable tile joints and replace it without damaging the tile edges.
Home · 2–3 hr + cure · Medium
Before you start
Wear eye protection against chips, gloves against cement irritation, and suitable respiratory protection while controlling dust. Do not dry-grind grout or use household vacuum exhaust to spread fine dust. Resolve suspect asbestos-containing legacy material before disturbing it. Stop for moving tiles, ongoing cracking, damp backing or a removal path that risks buried heating or waterproofing.
Tools and materials
- Hand grout saw sized narrower than the joint; HEPA vacuum and brush
- Compatible cement grout, clean mixing pail, measuring container and margin trowel
- Rubber grout float, grout sponge, clean water and soft cloths
- Eye protection, gloves, suitable dust protection and knee pad
Check the problem
Check whether the tiles are stable
Press gently around the affected joints and look for tile movement or cracks that continue across several tiles. Regrouting cannot stabilize a flexing floor or loose tile. If the grout is sound but discolored, try compatible cleaning instead of removing it.
Identify the joint and matching grout
Repair ordinary field joints with grout rated for the tile and joint width. Wall-to-floor corners and perimeter movement joints need the appropriate flexible joint treatment, not rigid grout. Confirm the old grout is cement-based and make a cured color sample; new grout may not match aged grout exactly.
Steps
Protect the edges and set up dust control
Clear the work area and clean the tile. Protect delicate nearby finishes and keep grit off the surrounding floor. Choose a hand grout saw narrower than the joint so it cannot scrape both tile edges at once. Have the vacuum nozzle ready beside the work.
Cut out the failed grout evenly
Work the hand saw along the joint with short controlled strokes, keeping the blade off the tile edges. Remove the damaged material to sound ends and to the replacement grout’s required depth—commonly at least two-thirds of the tile thickness. Do not cut through into the setting bed or waterproofing.
Vacuum and check the empty joints
Vacuum out loose particles and brush remaining dust free. Check for consistently open depth, firm tile edges and no loose old grout. Prepare moisture conditions as the grout label directs; leave no puddles or cleaner residue.
Measure and mix a small batch
Measure powder and clean water in the exact ratio on the bag. Mix as directed, including any required rest and remix. Make only what you can apply within working time. Never add extra water to revive stiffening grout or combine leftover partly set material with a fresh batch.
Press grout fully into the joints
Use the rubber float to press grout firmly into the cleaned joints from more than one direction. Work a small area and leave no voids. Turn the float more upright and sweep diagonally across the tiles to remove excess without scooping out the joints.
Shape the joints and remove haze
At the label’s cleanup stage, wipe lightly with a well-wrung grout sponge, rinsing often. Avoid flooding or repeatedly scrubbing the joints. After the stated interval, remove the remaining haze with a clean cloth or approved method. Do not use acid or abrasive cleaners on fresh grout.
Protect the repair and verify it cured
Keep traffic, cleaning and water off the repair for the specified cure times. Apply sealer only if the chosen grout requires it, after its stated wait. Inspect for firm, evenly filled joints without pinholes or cracks. If cracking returns or a tile moves, investigate the tile assembly rather than repeating the grout repair.
Cured joints are firm and continuous, tiles remain stable, and no cracks reopen after normal use.
Tips
Do not skim over failed grout
A shallow cosmetic layer has little to hold onto. The replacement needs the specified clean joint depth.
Measure water rather than guessing
Extra water can weaken grout and change its color. Use the same measured ratio for each batch.
Keep movement joints flexible
Do not bridge an existing movement gap with grout just because it matches the nearby joints.