Mr Mastic · South East, London and Scotland
Remedial sealant and repairs
Failed, botched, mouldy and leaking sealant taken out properly, the cause found and the joint resealed so it lasts.
- Sealant applied over old sealant that has lifted
- Leaks that keep coming back after resealing
- Black mould underneath the bead
What remedial sealant & repairs involves
Remedial work is what we do when sealant has failed or been done badly: new silicone laid over old, the wrong product in a moving joint, smears across the tiles, mould trapped underneath or a leak that keeps returning. We strip it all out, find out why it failed and reseal the joint the right way.
We work across the South East, London and all of Scotland from our base in Crawley. Every job comes with our one-year guarantee, and we’re fully insured and an ARBOMaster approved applicator.
Problems we put right
- Sealant applied over old sealant that has lifted
- Leaks that keep coming back after resealing
- Black mould underneath the bead
- Thick, messy sealant smeared over tiles
- Movement joints that have split or pulled away
Where we work
- Mouldy bath & shower sealant
- Botched or over-sealed joints
- Leaking tray & enclosure joints
- Failed movement joints
- Shrunken worktop sealant
- Expansion joints
How it works
- We look at how and where the sealant has failed and check for movement or a leak path.
- All the old sealant is cut and cleaned out, including any layers underneath.
- The joint is cleaned, treated for mould and left to dry.
- Where a joint moves, we use the right backing and a flexible sealant suited to that movement.
- The new joint is tooled neatly and we explain anything else we found that needs attention.
Finding the cause
If a joint keeps failing, there’s usually a reason: a tray or bath that moves, a worktop that isn’t fixed, the wrong sealant, or water getting in somewhere else. We look for the cause before we reseal.
When it isn’t the sealant
Sometimes a leak is a cracked tray, a failed shower valve or a waste. If so, we’ll tell you rather than reseal something that won’t fix it.
A real job
On Harper Drive in Maidenbower, Crawley, water was getting behind a kitchen worktop. The sealant was around 30 years old and had shrunk away from the wall. We stripped it out from the worktop joint, the upstand and around the sink, used a colour-matched sanitary silicone and a food-safe product by the sink, and finished the same day.
Why it’s worth doing now
A joint that keeps failing is telling you something: the wrong product, sealant laid over old sealant, a bath or tray that moves, or water getting in elsewhere. Resealing over the top again just repeats the problem. Remedial work fixes the cause as well as the joint.
What affects the quote
We don’t publish set prices, because every job is different. Call or email us with a few details and we’ll give you a clear quote before we start. The main things that affect it are:
- How many joints, rooms, windows or metres of joint there are
- How much old sealant or grout has to come out, and how many layers
- Mould, damage or movement that needs dealing with first
- Access: stairs, height, ladders or work outside
- The product the joint needs (sanitary, exterior, fire-rated, glazing or sand mastic)
- For commercial sites, working hours and phasing
What a good quote includes
- All the old sealant removed, not sealed over
- The product named for each joint
- How long the guarantee is and what it covers
- How long before the area can be used
- How your home or building will be protected
- Who is doing the work, and that they’re insured
Aftercare
Give the new joint its full cure time before use. If a joint moves, avoid anything that loads it while it cures, such as standing in a newly sealed tray, and tell us straight away if you see the same failure returning.
What customers say
Rated 4.9 on Google from 180+ five-star reviews. Read the reviews on Google.
“Called for a bathroom reseal and the mastic man showed up on time with all the right equipment. Brilliant attention to detail. The sealant looks perfect and they kept everything tidy.”
“We had old mastic that needed replacing throughout our kitchen and bathrooms. The mastic man professional was knowledgeable, quoted fairly, and delivered excellent quality work. Highly recommend!”
“Professional mastic man service from start to finish. They assessed the work properly, gave a clear quote, and executed the job perfectly. Very satisfied with the results.”
Remedial sealant and repairs: common questions
Someone resealed my shower and it’s leaking again. Can you help?
Yes. We’ll take all of the sealant out, look for why it failed and reseal it properly.
Can you remove sealant that’s been put over old sealant?
Yes. Both layers come out; new silicone doesn’t bond to old silicone, which is why over-sealing fails.
Do you fix expansion and movement joints?
Yes. Failed movement joints are cut out and resealed with backing and a flexible sealant suited to the movement.
Is the work guaranteed?
Yes. Every job comes with our one-year guarantee.
Do you give a price before you start?
Yes. Call or email us with a few details and we’ll give you a clear quote, so you know the price before any work starts.
Are you insured?
Yes. Mr Mastic is fully insured, and we’re an ARBOMaster approved applicator.
Page updated 26 October 2026
Near you
We cover the South East, London and Scotland. Find remedial sealant & repairs in your town:
- London
- Crawley
- Brighton
- Guildford
- Chelmsford
- Colchester
- Southampton
- Reading
- Oxford
- Edinburgh
- Glasgow
- Aberdeen
- Dundee