If your tiles are firmly stuck to the wall and only the grout and silicone look tired, stained or mouldy, regrouting and resealing will usually make them look close to new and is far less work than retiling. If tiles sound hollow, move when pressed, have water getting behind them, or the wall underneath is soft, the tiles need to come off, because fresh grout on a failing wall only hides the problem for a while.

Why this matters more than looks

Grout and silicone are the waterproofing details of a tiled wall. Tiles themselves shed water well, but water finds its way through cracked grout and failed sealant. Once it is behind the tiles, it soaks into plaster or plasterboard, weakens the adhesive and eventually loosens tiles or rots the timber below a shower tray. Catching tired grout and sealant early is what stops a cosmetic job turning into a strip-out.

We should be clear about what we do. Vantage does not offer a specialist tile restoration service, such as deep-cleaning or recolouring grout, or resurfacing tiles. We repair tiled areas properly, replace damaged tiles, and retile walls and floors through our bathroom tiling service. This guide helps you work out which of those you need.

How to tell whether tiles can be saved

Go through these checks on each tiled area, especially around the shower and bath.

1. Tap test. Gently tap tiles with a knuckle or the handle of a screwdriver. A solid, dull sound is good. A hollow, drummy sound means the tile has lost contact with the adhesive or the wall.
2. Press test. Press firmly on tiles near the shower and bath edge. Any movement means the bond has failed.
3. Look at the grout lines. Crumbling, missing or cracked grout, particularly in a line along the same joint, can mean movement behind.
4. Check the silicone. Peeling, gaps, or black mould growing under the surface rather than on it means the seal has failed.
5. Look below and around. Stains on the ceiling underneath, a musty smell, swollen skirting or flooring next to the bath, or loose flooring near the tray all suggest water is escaping.
6. Check the wall around the edges. Soft plaster, bubbling paint or plasterboard that gives when pressed at the edge of the tiling is a warning sign.

If everything is solid and dry, and the problem is only appearance, regrouting and resealing is the right job. If any of checks 1, 2, 5 or 6 fail, the tiles need to come off in that area.

Regrouting: what it involves and when it works

Regrouting means removing the old grout and replacing it, not adding a thin layer on top. Grout applied over old grout does not bond properly and tends to flake and chip away. Tile manufacturers and retailers advise raking out old grout to a depth of at least 3mm, and deeper is better, so the new grout has enough to grip.

Regrouting works well when:

• the tiles are sound and well fixed
• the grout is stained, discoloured or has surface mould
• the grout has cracked because it was mixed or cured poorly, not because the wall is moving

It is less effective when grout keeps cracking along the same lines. That usually means movement in the wall or floor behind, such as flexing floorboards under floor tiles or a stud wall that was never stiff enough. Regrouting treats the symptom. The fix is to strengthen the base and retile.

Resealing: the part most people miss

Where tiles meet a bath, shower tray, basin or worktop, and in internal corners, the joint should be flexible silicone sealant, not grout. These joints move slightly as the bath fills, as the tray takes weight, and as the building heats and cools. Rigid grout in those joints cracks and lets water in.

Resealing properly means cutting out all the old silicone, cleaning off every trace of residue and mould, making sure the joint is dry, and applying a continuous bead of sanitary-grade silicone. For a bath, filling it with water before sealing means the joint is sealed at its widest, so it is less likely to tear when the bath is used. Our guide on how to seal a bath goes through the steps.

Replacing individual tiles

A single cracked or chipped tile can usually be cut out and replaced without disturbing its neighbours, as long as you can get a match. That is the catch: tile ranges are discontinued often, and a slightly different shade or thickness stands out. If you kept spare tiles when the bathroom was fitted, this is what they are for.

Before replacing a cracked tile, find out why it cracked. Something dropped on it is one thing. A crack running across several tiles, or a cracked floor tile next to a toilet or bath, can point to movement or a leak underneath.

Regrout, replace or retile: compared

Situation	Best option	Why
Sound tiles, stained or mouldy grout	Regrout	Tiles are fine, only the grout has failed
Mould or gaps in silicone around bath or tray	Cut out and reseal	Silicone is a wear item and needs renewing
One or two cracked tiles, matches available	Replace individual tiles	Least disruption if the wall is sound
Grout keeps cracking along the same lines	Investigate, likely retile	Movement behind means the base needs fixing
Hollow or loose tiles in the shower area	Retile that area	The adhesive bond has failed, water is likely behind
Soft or damp wall behind tiles	Strip, repair, retile	The wall itself must be sound and dry first
Leak stains below the bathroom	Find the leak first	Tiling over a leak repeats the damage

When retiling is the better investment

Retiling is more work, but there are times it is plainly the better choice:

• tiles in the shower area are hollow or loose
• the wall behind is damaged by water and needs replacing or waterproofing
• you cannot match damaged tiles and the patch would look obvious
• you are changing the shower or bath anyway, which usually disturbs the tiles
• the tiling was never fixed well in the first place

In a shower, retiling is also the chance to fix what caused the failure: a suitable tile backer board or a tanking system on the wall, correct movement joints and silicone at every junction, and a well-supported tray. If you are thinking about the floor too, our guide to choosing bathroom floor tiles covers slip resistance and suitable materials.

Mistakes to avoid

• Grouting over old grout instead of raking it out.
• Using grout in the joint between the bath and the wall.
• Sealing over old silicone or mould instead of removing it.
• Using the shower before the grout and silicone have fully cured. Follow the product’s instructions.
• Regrouting a wall where tiles already sound hollow.
• Throwing away spare tiles after a bathroom is fitted.

What it costs with Vantage

Small tiling repairs, such as replacing a few tiles or resealing around a bath or tray, are charged like our other repair work. In normal working hours there is no call-out fee. After the first hour, time is charged in half-hour steps, and materials are quoted before we use them. Evening, weekend and overnight visits are charged at the out-of-hours rates. Retiling and larger bathroom work is quoted as a fixed price after a free survey, so the price you agree is the price you pay. Every rate is published on our prices page. Our work carries a 12 month labour guarantee, and bathroom installations a 12 month guarantee.

Frequently asked questions

Can you put new grout over old grout?

Not successfully. New grout will not bond well to old grout and will flake away. The old grout needs raking out to a depth of at least 3mm before regrouting.

Is regrouting worth it?

Yes, if the tiles are well fixed and the problem is only stained, cracked or mouldy grout. It can transform the look of a bathroom. It is not worth doing on tiles that are hollow or loose.

How do I know if water has got behind my tiles?

Hollow-sounding or loose tiles, grout that keeps cracking, a musty smell, soft wall edges, and stains on the ceiling below are all signs. A tray or bath that flexes when you stand in it is another warning.

Should grout or silicone go in bathroom corners?

Flexible silicone should go in internal corners and wherever tiles meet a bath, shower tray, basin or worktop. Grout is for the joints between tiles on a flat surface.

Can one cracked tile be replaced?

Usually, if you have a matching spare and the wall behind is sound. Find out why it cracked first, especially on a floor or in a shower.

Help with tiling in Hertfordshire, Bedfordshire and Cambridgeshire

If you are not sure whether your tiles can be saved or need replacing, we can take a look, fix the cause and retile properly where it is needed. See our bathroom tiling service or call 01462 506374.