# Cracked or missing grout: how to fix it

Updated: 2026-10-24 · https://pros411.com/en/guides/handyman/cracked-or-missing-grout

## Short answer

Rake out the cracked grout with a grout saw, about 1/8 inch deep or down to solid grout, and vacuum the joints. Mix new grout to the bag directions and press it in with a rubber float at an angle. Wipe the haze with a damp sponge, let it cure for the time on the bag, then seal it. Use caulk, not grout, in corners and where tile meets the tub.

## How to fix cracked grout

![Cartoon bathtub scared of cracked, crumbling grout, with a grout saw on the way](https://pros411.com/img/guias/cracked-or-missing-grout.webp)

1. **Cracks and holes in the grout.** Cracked or crumbling grout lets water behind the tile. Press on the tiles nearby: if they move or sound hollow, the problem is bigger.
2. **Rake it out with a grout saw.** Saw along the joint until you reach solid grout, about 1/8 inch deep. Vacuum the dust and wipe the joints with a damp sponge.
3. **Press in new grout at an angle.** Mix a small batch to the bag directions. Hold the rubber float at about 45 degrees and push the grout across the joints until they are full.
4. **Wipe the haze with a damp sponge.** When the grout is firm, wipe across the joints with a damp, not wet, sponge. Rinse it often. Buff off the dry haze later with a soft cloth.
5. **Let it cure, then seal it.** Keep water off for the cure time on the bag. Then brush grout sealer onto the new joints so they shed water and stains.

## Why grout cracks

Grout is stiff. When the house settles, the tub moves or a tile flexes, the grout cracks instead of bending. Corners and the joint above the tub crack first, because two surfaces meet there and move on their own. That is why those joints get caulk. Grout that keeps cracking in the same spot often sits over a loose tile.

## What not to do

- Do not smear new grout over old grout. A thin layer flakes off within weeks.
- Do not grout the corners or the tub joint. Use a matching silicone caulk there.
- Do not soak fresh grout with a wet sponge. Extra water weakens it and leaves it blotchy.

## Sanded or unsanded grout

Joints wider than 1/8 inch take sanded grout. Narrower joints, and soft tile like polished marble, take unsanded grout. Pre-mixed grout in a tub is easy for small repairs. Bring a chip of the old grout to the store to match the color.

## When to call a handyman

- Tiles around the bad grout are loose, hollow or cracked.
- The wall behind the shower feels soft, or there is a stain on the ceiling below.
- The grout keeps cracking in the same place after you fix it.
- Large areas need new grout, or the shower is leaking.

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## Frequently asked questions

### Can I put new grout over old grout?

Not as a thin layer on top. Rake the old grout out at least 1/8 inch deep, or until it is solid, so the new grout has room to bond. A skim coat on top flakes off.

### Why is my grout cracking?

Movement. The house settles, the tub shifts or a tile is loose, and stiff grout cracks. Corners and the tub joint should be caulked, not grouted. If the cracks keep coming back, check whether the tiles move.

### How long does grout need before I can shower?

It depends on the product, so follow the bag. Most cement grout needs at least a day before it gets wet and longer to cure fully. Wait until it has cured before you seal it.

### Do I need to seal grout after repairing it?

Yes for cement grout, once it has cured. Sealer helps it shed water and stains. Epoxy grout and many pre-mixed grouts do not need sealing; the label says so.

### What tool removes old grout?

A grout saw with a carbide blade is enough for small repairs. For a whole shower, an oscillating tool with a grout blade is faster, but go slowly so you do not chip the tile edges.