Almost nobody wants to retile a bathroom. It is disruptive, it costs more, and in a flat it drags in consent, access and a household without a shower. So when the grout goes dark, cracks along an edge, or starts falling out around the bath, the hope is always that a regrout will do.
Sometimes it will, and it is genuinely good value when it is the right answer. But grout is the surface a problem shows on, not usually the problem itself. Regrouting a bathroom whose real fault is elsewhere buys you a good-looking room for a few months and no more. So the honest first job is diagnosis, and that is what this page is about.
What grout is actually for
Worth clearing up, because it drives everything else. Grout fills the joints between tiles, keeps dirt out, and helps the tiles work together as a surface. It is not the waterproofing. Grout is porous to some degree, and it is not what stops water reaching the structure behind. That job belongs to the tanking or membrane behind the tile, or in an older bathroom, to whatever was there instead, which is often nothing at all.
Once you accept that, the diagnosis gets easier. Failing grout does not, by itself, mean the bathroom is leaking. And perfect grout does not mean it is not.
When regrouting is the right call
Regrouting is appropriate when the tiles and the installation behind them are sound and the grout has simply reached the end of its life as a surface. The signs are reassuringly boring.
The tiles are firmly fixed. Tapped across the wall or floor, they sound consistent — no hollow patches. The grout is discoloured, stained, or worn but not moving, and the failure is broadly even across the room rather than concentrated in one line. There is no sign of movement: no cracks running through tiles, no cracked grout tracking in a straight line across a floor. Nothing is soft. The ceiling below is dry and has always been dry.
That is a cosmetic problem with a cosmetic answer, and a proper regrout — raking out to a decent depth rather than smearing new grout over old, cleaning the joints, and re-grouting with an appropriate product — will give you a room that looks new for a fraction of a retile. Mould in the joints of an otherwise sound bathroom often sits here too, though mould that keeps coming back is frequently a ventilation problem rather than a grout problem, and regrouting will not fix a room that cannot dry out.
When grout is a symptom, not the fault
These are the signals that say stop, because a regrout would be papering over something.
Hollow tiles are the clearest. If tiles sound drummy when tapped, the adhesive bond has failed, and grout is not holding anything together. Regrouting around a debonded tile is decoration.
Cracks that run in a line matter more than cracks that are scattered. Grout cracking along a consistent line across a floor generally means the floor is moving, which in a Central London flat usually means a timber deck flexing under a rigid finish. Grout is simply the weakest thing in the assembly, so it goes first. Regrout it and the same line will reopen, because nothing about the movement has changed. The fix is under the tile, not in the joint, which is the same argument set out in our guide to large-format tiles in London flats.
Cracks through tiles rather than joints say the same thing, louder.
Grout failing in one concentrated area, particularly in a shower or around a bath, is a water signal. It often means water has been getting behind and the background is softening. If the plaster or board behind is wet, no grout will save it.
And the decisive one: any sign of water reaching the flat below. A stain on their ceiling, or a mark on yours from the flat above, moves this out of the cosmetic category entirely. In a flat, a leaking shower is not your problem — it is your neighbour's ceiling and, quickly, an insurance and managing-agent conversation. That deserves investigation before anything is made to look nice, and it may need a plumber as much as a tiler.
The perimeter is not a grout question
One specific failure is worth separating out, because it is extremely common and constantly misdiagnosed.
Where tiling meets the bath, the shower tray, the worktop, or the floor at a wall, that junction moves. A bath full of water and a person in it deflects; empty, it comes back. That junction needs a flexible sealant, not rigid grout. Fill it with grout and it will crack, every time, and no amount of regrouting will change the physics. If your only failure is a hairline crack along the top of the bath, the answer is usually to rake it out properly and seal it correctly, which is a small job rather than a bathroom.
The related point is that silicone has a life. It discolours, it harbours mould, and it eventually lets go. Replacing it periodically is maintenance, not failure, and it is the sort of thing our maintenance work handles quickly.
What regrouting will not do
Be clear-eyed about the limits before you spend.
It will not make an untanked shower waterproof. It will not stop a floor moving. It will not re-bond a hollow tile. It will not fix a bathroom that has no adequate extraction and therefore never dries — that is a ventilation issue, and bathrooms engage Part F of the Building Regulations for ventilation, alongside Part G for sanitation and hot water and Part P for electrics. It will not correct bad setting out or lipping. And it will not change the colour of your tiles, though it can change the character of the room more than people expect, because grout colour is a large part of what you actually see.
How the two jobs compare in practice
We do not publish a price range for either, because the honest number depends on the room. What we can be clear about is the shape of the difference.
A regrout is a surface operation. It is dust and mess for a short period, the room is usable again quickly, nothing structural is touched, and it is very unlikely to need anyone's consent. It is contained.
A retile is a different animal. It is a strip-out, and in a period flat the old tiles frequently take the plaster with them, which means the background has to be made good before anything new goes on — often the biggest single item, and not visible in the finished room. It may reveal that there was never any tanking. It means waste out through communal parts, materials in, days of noise, and a bathroom out of use. Our tiling starts from £55/m², published, and both jobs are confirmed by a fixed quote once we have seen the room; what drives that figure is set out in our guide to tiling cost per square metre.
The trap is the middle case: regrouting a bathroom that needed retiling. You pay for the regrout, you get six months, and then you pay for the retile anyway. That is the most expensive route available, and it is chosen with good intentions every day.
If it is a retile: the Central London part
Once you are retiling, the building gets involved.
Most leases require the freeholder's or managing agent's consent for alterations, and bathrooms are one of the areas leases treat most carefully, particularly anything touching waste or soil pipes or changing the floor build-up. A straight like-for-like retile is generally less contentious than a reconfiguration, but you should check your lease and confirm with your managing agent rather than assume — our guide to freeholder consent for a bathroom refurbishment covers what to ask, and where more substantial alterations are involved a formal licence to alter may be required.
Then the practicalities. Waste and materials cross communal parts, the lift needs booking and protecting with the porter, and there is nowhere to park. Noisy work, and stripping tile is noisy, is commonly restricted to set hours in Westminster and under individual block rules, as covered in our guide to working hours restrictions. If the bathroom is the only one in the flat, the programme has to account for a household without it.
And if you are stripping back anyway, it is worth asking whether a retile is the right scope at all. Once the tiles are off and the background is being rebuilt, a fair share of the cost of a full bathroom refurbishment — from £2,800 — is already being spent. Retiling around a suite you dislike, which you then replace in three years, is a false economy worth naming out loud.
How to work out which you need
Tap the tiles and listen for hollows. Look at whether the failure is even or concentrated. Look for lines rather than scatter. Press the grout and the background in the shower and see if anything gives. Check the ceiling below, and ask the flat below whether they have ever seen a mark. Establish whether there is any tanking, which in an older bathroom usually means finding out when it was last done and by whom. If the answers are all reassuring, regrout. If any of them is not, find out why before you spend.
What you get from us
We would rather tell you a regrout will do than sell you a bathroom you do not need — and rather tell you it will not than take your money twice. We look at the room, tap the tiles, check for movement and water, and tell you which job you are actually buying. Whichever it is, you get a fixed quote before we start, protection of the communal parts, and the flat left clean. If you want a first view, send a photograph through the quote form or on WhatsApp.