Regrouting
Regrouting or resealing: which does your wet area need?
5 min read
Short answer
Regrouting replaces the cement-based grout between tiles. Resealing replaces the flexible silicone in the junctions where two surfaces meet, such as wall to floor and internal corners. Sealing grout is different again: it applies a penetrating sealer to existing grout to slow water absorption. Most wet areas that are failing need the first two, and they are usually done together.
These three terms get used interchangeably, including by people selling the work, and the confusion causes real problems. Each one addresses a different failure, and paying for the wrong one is a common reason a wet area is back in the same condition a year later.
Regrouting
Regrouting means removing the existing grout from between the tiles and installing new grout in its place. The removal is the part that matters. Grout laid on top of old grout has almost nothing to bond to and a very shallow depth, so it cracks and washes out quickly.
It is the right answer when grout is cracked, crumbling, powdery, missing in patches, stained beyond cleaning, or when the joints are letting through more water than the assembly can cope with.
What it does not do is repair a waterproof membrane. Grout is not waterproofing, and it was never intended to be. It is a filler that keeps water moving across the surface toward the drain rather than sitting in the joints.
Resealing
Resealing means cutting out the old flexible sealant and installing new sealant in the junctions: wall to floor, internal corners, around the waste, at the shower screen, and where the tiles meet a bath or basin.
Those junctions are the parts of a wet area that move. Buildings settle, materials expand and contract with temperature, and a shower base flexes slightly under load. A rigid cement grout in a moving joint will crack, which is why those junctions take a flexible sealant instead.
Grout in a junction that should have been sealed is one of the most common defects we find, and it is often what caused the leak in the first place.
Sealing the grout
This is a penetrating sealer applied to existing grout to reduce how much water it absorbs and to make it easier to clean. It is maintenance, not repair.
It is worth doing on sound grout in good condition. It is not worth doing on grout that is cracked, crumbling or debonded, because a sealer applied over a failed joint just seals a failed joint. If someone offers to seal grout that is visibly breaking down, that is the wrong product for the problem.
Why they are usually done together
A wet area is a system. If the grout has reached the end of its life, the silicone installed at the same time generally has too, because both have been exposed to the same water, heat and cleaning products for the same number of years.
Doing the grout and leaving perished silicone in the junctions means the most likely entry point for water is still there. The area looks renewed and behaves exactly as it did before.
What good preparation looks like
- Old grout ground out of the joints to a proper depth, not skimmed over.
- Old sealant cut out completely, not covered with a new bead.
- Joints cleaned of dust and debris so the new material can bond.
- Mould-affected areas treated during preparation rather than sealed in.
- Flexible sealant in the junctions, cement grout in the field.
- A stated curing time before the area is used again.
In short
- Regrouting replaces grout. Resealing replaces silicone. Sealing treats grout that is still sound.
- Grout is not waterproofing, and neither is silicone. The membrane under the tiles is.
- Joints that move take flexible sealant. Grout in a moving joint will crack.
- New grout over old grout fails, because it has nothing to bond to.
Common questions
- How often does a shower need regrouting?
- There is no set interval. It depends on how heavily the shower is used, how well it ventilates, what cleaning products are used on it, and how well the original work was done. Condition is a better guide than age: cracked, crumbling or missing grout needs replacing regardless of how recently it was done.
- Can I regrout over the top of existing grout?
- It is possible to apply grout over old grout, but it does not last. The new material has very little depth and nothing sound to bond to, so it tends to crack and wash out. The old grout has to be ground out for the repair to be durable.
- Does regrouting stop a leak?
- It stops leaks that are caused by water passing through failed joints at the surface. It does not stop leaks caused by a failed waterproof membrane, a plumbing fault or an incorrect floor fall, because none of those are at the surface.
Related service: Regrouting