Mouldy, crumbling or discoloured silicone sealant around the bath, shower and basin is one of the most common bathroom problems in UK homes. It looks unhygienic, is impossible to fully clean once mould has penetrated the sealant core, and can allow water ingress that leads to damage behind walls and under floors. Professional sealant replacement is a straightforward service that transforms the appearance of a bathroom in a single visit.
Why Bathroom Silicone Sealant Goes Mouldy
Silicone sealant in bathrooms serves as a flexible waterproof joint in movement zones — around the bath rim, at the base of the shower enclosure, around the basin and at tile-to-floor junctions. It needs to flex with the natural movement of bathroom surfaces (baths flex when filled with water; shower trays flex under body weight).
The conditions that make bathrooms wet also promote mould growth — and silicone’s slightly textured surface, once colonised by mould spores, is almost impossible to fully clean. Surface mould can be bleached back temporarily, but once mould has grown into the silicone body, only full replacement removes it. This typically takes 2–3 years in a regularly used bathroom with normal ventilation.
Signs It’s Time to Replace Your Sealant
- Black or dark grey mould visible in or on the sealant
- Sealant peeling away from the bath, tile or tray
- Visible gaps between the sealant and the adjacent surface
- Sealant has hardened and cracked (particularly at flex points)
- Persistent smell from the sealant area despite cleaning
- Sealant discoloured yellow, brown or green despite cleaning
Why DIY Sealant Replacement Often Goes Wrong
DIY sealant replacement is one of those jobs that looks simple but is frequently botched. The most common problems include: old sealant not fully removed (the new sealant won’t adhere properly over old sealant), application not smoothed correctly (visible ridges and bumps), air pockets creating weakness points, and mismatch between the bath/tile colour and the sealant colour. Professional sealant replacement uses the correct primers where needed, achieves a smooth professional finish, and ensures the sealant is fully bonded for long-term waterproofing.
What Professional Sealant Replacement Involves
The existing sealant is removed completely using specialist removal tools — mechanical and chemical removal ensures no residue is left. The joint surface is cleaned and dried. New silicone sealant is applied using a gun and immediately tooled to a smooth, concave bead profile. The tape masking is removed before the sealant skins. The result is a clean, smooth, hygienic sealant bead that will last 3–5 years or more in normal use.
Sealant Colour and Finish
We match sealant colour to your bathroom — bright white, cool white, grey, cream, anthracite and other colours available. Anti-mould formulations extend the clean life of the sealant.
Get a Sealant Replacement Quote
Send photos of the sealant areas to be replaced for a free assessment and quote. Sealant replacement is often carried out alongside other surface repairs in the same bathroom visit.
