If water is getting past the seal around your bath or shower, the sealant has usually failed and needs replacing. The good news is that a leak rarely means the bath or shower itself has to come out.
We’re The Mastic Guys, and fixing leaking baths and showers across Chelmsford and the rest of Essex is what we do every day. Below are the signs we look for on a job, why an extra layer of silicone almost never works, and how to tell when a leak needs more than a reseal.
Signs your bath or shower sealant needs replacing
Sealant doesn’t last forever. Water, cleaning products, changes in temperature and everyday movement all wear it down over time. These are the signs to look for.
Cracked, split or brittle sealant
Cracks and splits are the clearest sign a seal has stopped doing its job. Even a hairline crack lets water through, and around a shower, that happens every time it’s used.
If the sealant feels hard and brittle or is crumbling away, it’s time to replace it.
Sealant peeling away from the wall or tray
Good sealant forms one continuous bond between the bath or shower tray and the wall. If you can see it lifting at the edges or pulling away from either side, water can get in behind it.
We see this most often where the bath or tray moves slightly when someone stands in it.
Black mould that keeps coming back
Some surface mould comes down to poor ventilation and steam. But if the sealant has turned black and stays black after a good clean, the mould is usually inside the silicone itself.
At that point, no amount of scrubbing will fix it. The old sealant needs to come out, and we replace it with an anti-fungal silicone to help stop the mould returning.
Gaps and pinholes
Run your eye along the whole length of the seal. Gaps, pinholes and sections where the sealant has disappeared give water an easy way in.
Check the corners and joints closely. They take the most movement, so they’re usually the first to go.
Water escaping while you use the bath or shower
If you can see water getting past the seal while the shower is running, don’t leave it. Water behind a failed seal reaches timber, plasterboard and ceilings that were never meant to get wet.
The longer it goes on, the bigger the repair bill is likely to be.
Damp, staining or damage nearby
Loose tiles, crumbling grout, staining, damp patches or bubbling paint near the bath or shower all suggest water has been getting behind the seal. If your bathroom is upstairs, check the ceiling underneath it too.
It doesn’t always mean there’s a big underlying problem. It is a reason to have the area looked at properly rather than adding another layer of silicone.
Why you shouldn’t put new sealant over the old seal
It’s tempting to run a fresh bead of silicone over tired, mouldy sealant. It might look better for a few weeks, but it won’t last.
New silicone needs a clean, dry, properly prepared surface to bond to. Old sealant stops it from gripping, and any mould, dirt and moisture underneath stays trapped there.
That’s why every job we do starts the same way. We remove all of the old mastic, clean and prepare the surfaces, and only then apply the new sealant. The prep often takes longer than the sealing itself, but it’s the difference between a seal that lasts and one you’re redoing next year.
Could movement be causing your seal to fail?
Not every failed seal comes down to poor sealant. Movement is one of the most common causes we see.
A bath can drop slightly when it’s filled or when someone gets in, especially if it isn’t properly supported underneath. Shower trays can flex under weight too. Each time, the sealant is stretched, and eventually it splits or pulls away.
When we reseal a bath, we fill it with water first so it sits at its lowest point while the new sealant cures. If a bath or tray is moving more than it should, that needs sorting before resealing, or the new seal will fail in exactly the same way.
Is resealing enough, or is there a bigger problem?
In most of the leaks we are called out to, a failed seal is the cause and a proper reseal fixes it. But if a bath or shower has been correctly resealed and water still escapes, the leak is coming from somewhere else. Common culprits include:
- a leaking waste or trap under the bath or tray
- blocked drain channels on a shower tray, so water pools and finds another way out
- a bath or shower tray that moves too much
- cracked tiles or failed grout
- a shower screen or enclosure that has been fitted badly
Applying more sealant won’t fix any of these, which is why a persistent leak needs investigating. It also doesn’t mean you need a new bath or shower. Where a gap is too wide for silicone alone, for example, we can fit a sealant trim instead.
Mastic repair in Chelmsford from The Mastic Guys
We remove failed sealant, prepare the area properly and reseal using premium sealants, colour-matched to your bathroom at no extra cost. Every mastic job comes with our 2-year guarantee against leaks.
We work across Chelmsford and the surrounding area 7 days a week, with weekends at no extra cost. If you need mastic repair in Chelmsford, we’ll tell you honestly whether a reseal will solve the problem or whether something else needs attention first.
Get your bath or shower resealed
Cracked or peeling sealant, mould that won’t shift, and water escaping around your bath or shower won’t get better on their own. The sooner it’s sorted, the less chance water has to reach the floor, walls or ceiling below.
Call The Mastic Guys on 01245 379300 for advice and a free quote, or find out more about our mastic repair service.