Why acrylic baths crack
An acrylic bath is a thin acrylic sheet reinforced underneath. It relies on its cradle, feet and the wall battens to stay rigid. If the support is poor, or the feet weren’t adjusted properly, the bath flexes when it’s full and the acrylic eventually cracks. Dropped heavy items and over-tightened taps cause cracks too.
Hairline crack or structural crack?
- Surface (hairline) cracks only affect the top layer. They look like a fine line and don’t let water through.
- Structural cracks go right through. You may feel movement, hear a creak, or see water marks on the ceiling below.
If water is getting through, stop using the bath until it’s fixed.
How a proper repair is done
A lasting repair needs support from behind. We remove the bath panel, reinforce the back of the crack, then fill and refinish the front and colour-match it to the bath. Filling only from the top doesn’t stop the bath flexing, so top-only repairs usually reopen.
Check access first
Take the bath panel off and see if you can reach the back of the cracked area by hand. Cracks on the sides and near the taps are usually reachable. Cracks in the base can be harder if there’s a board underneath. Send us photos of both sides and we’ll tell you if it’s repairable.
Fix the cause too
If the bath moves when you stand in it, the feet or cradle need adjusting or packing out, otherwise a repair can crack again. We’ll point out anything we see.
How acrylic baths are built
Most acrylic baths are made from a sheet of acrylic heated and vacuum-formed into shape, then strengthened underneath with layers of resin and glass fibre, and sometimes a board in the base. The acrylic gives the smooth, warm surface, and the reinforcement gives it stiffness. The bath sits on a cradle or adjustable legs and is fixed to the walls along the rim.
Because the sheet itself is fairly thin, the bath only stays rigid if all of that support is doing its job. When it isn’t, the bath flexes every time it is filled or stood in, and the acrylic eventually cracks.
Where cracks usually appear
- The base, where people stand to shower, especially on baths with a shower over them.
- Around the waste and overflow, where fittings are tightened against the acrylic.
- Near the taps, if they were overtightened or the deck flexes.
- Corners and edges, after something heavy has been dropped.
What to do as soon as you notice a crack
- Stop using the bath, or at least stop showering in it, until you know whether the crack goes through.
- Check below. Look for damp, stains or bubbling paint on the ceiling underneath, or water under the bath if you can lift the panel.
- Keep it dry. If water may be getting in, a strip of waterproof tape over the crack can help for a few days, but remove it before a repair.
- Take photos of the crack, the whole bath, and the area under the bath with the panel off. These are what we need to tell you whether it can be repaired.
Why sealant and filler alone don’t work
Running silicone or filler into a crack from the top can stop a drip for a while, but it doesn’t stop the bath flexing. Every time the bath moves, the crack opens and closes, the filler breaks away and water gets back in. Filling also makes a later repair harder, because it all has to be removed. A lasting repair stiffens the back of the crack first, then fills and refinishes the front.
Making sure it doesn’t crack again
A repaired crack will only last if the reason the bath was flexing is dealt with. Common fixes include adjusting the legs so they all carry weight, packing out the base so it is properly supported, and making sure the rim is fixed to the walls. On a bath used as a shower, a well-supported base matters most. We’ll point out anything we see when we repair the crack, and we can tell you whether it needs a plumber or fitter.
Hairline crazing versus cracks
Fine spider-web lines in the surface, called crazing, are different from a crack. They are usually caused by harsh chemicals or age and don’t go through the acrylic. Crazing is a surface problem that can usually be polished or resurfaced, whereas a crack that you can feel with a fingernail or that weeps water is a structural problem.
Cracks in other acrylic and plastic items
Acrylic and plastic-capped shower trays, basins and whirlpool baths crack for the same reasons as acrylic baths: flexing, poor support and impact. The repair method is similar, with reinforcement behind and a refinish on top. Whirlpool and spa baths have pipework and jets behind the shell, so access can take more planning. See shower tray repair.
Repair or replace?
A standard-size acrylic bath that comes out easily may be cheaper to replace than repair. If replacing means re-tiling or moving plumbing, a repair is usually the better choice.
Quick answers
How long does a crack repair take?
Usually a couple of hours, plus curing time before the bath is used. We’ll tell you when you can use it.
What does it cost?
Our repairs start from £95. A crack that needs reinforcing behind costs more than a simple chip, and we confirm the price from your photos.
Is the repair guaranteed?
Yes, every repair comes with our one-year guarantee, as long as the bath’s support is sound.
Can you repair a hole as well as a crack?
Yes. See hole in an acrylic bath.
Every job is different. Send us a photo and we’ll tell you what we’d recommend for your bath, sink or surface.
