Silicone and mastic removal

Why removal is most of the job

New silicone doesn’t bond to old silicone. If a fresh bead goes over the top of a failed one, it sits on a surface it can’t grip, and it lifts, often within weeks. Any mould left underneath carries on growing and shows through. That’s why the most common problem we’re called out to fix is a joint someone has resealed over the old sealant.

Getting every trace of the old sealant out is the slow, careful part of resealing, and it decides how long the new joint lasts.

How we remove old sealant

1. We cut along both edges of the old bead, where it meets the tile and where it meets the bath, tray, basin or worktop, and lift it out.
2. Any layers underneath come out too. Older joints sometimes have two or three beads stacked on top of each other.
3. Residue left on the surfaces is cleaned off, so nothing stops the new sealant bonding.
4. The joint is treated for mould, cleaned and left to dry.
5. A new bead of the right sealant is laid and tooled neatly.

We use tools and methods suited to the surface, so acrylic baths, enamel, glass and stone aren’t scratched.

A real example: Crossways, Three Bridges

In a 1950s terrace on Crossways in Three Bridges, Crawley, black mould kept coming back around the bath however often it was cleaned. Someone had sealed straight over the old, failed sealant, so the mould was trapped underneath from the start. We took both layers out, cleaned and dried the joint and resealed with Everbuild anti-fungal white silicone. The job was done in under three hours.

Where we remove sealant

• Baths, shower trays, enclosures and screens
• Basins, sinks, kitchen worktops and upstands
• Window and door frames, inside and out
• Movement and expansion joints
• Glazing and conservatory joints

Removal is part of every reseal we do, and we reseal in the same visit so the joint isn’t left open to water.

Doing it yourself?

If you’d like to try it yourself, our guide on how to remove old silicone takes you through it step by step, and can you seal over old silicone? explains why it all has to come out. If the old sealant is very old mastic on a building from before 2000, read our note on asbestos in old mastic before you start.

What it costs

We don’t publish set prices. The time it takes depends on how much old sealant there is, how many layers, and what it’s stuck to. Call or email with a few details (photos help) and we’ll give you a clear quote for removing and resealing before any work starts.