Greater London · England
New-build mastic & snagging in New Charlton, Greater London
Professional new build mastic in and around New Charlton, with every bit of old sealant taken out first.
- Smeared, uneven beads picked up at snagging
- Beads laid onto grit and dust from the build
- Plot mastic for developers ahead of handover
New build mastic in New Charlton, done properly
We never seal over a failed new-build bead. Fresh silicone cannot bond to the old layer, so the joint is cut out, cleaned, dried and resealed. If you have messy sealant that spoils new finishes and gaps opening as the house dries out and settles, we can put it right, on kitchens, bathrooms & en suites and skirting & floors alike.
New flats are going up across London, many of them in larger developments. In a new development, snags are often reported through the developer or the managing agent, and shower seals that fail early, skirting joints that open up and gaps at thresholds are all common snags.
All our work comes with our 12-month guarantee.
- Location
- New Charlton (SE7, SE18, E16)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Why it’s worth doing now in New Charlton
A quick bead over the top of the old sealant can look fine at first, but it can’t bond to what’s underneath. Taking it all out and starting again is the only way to get a lasting seal. In London conversions, one flat’s bathroom is often above another flat’s ceiling, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Dealing with it early is far simpler.
Rather than a set price list, we price the job in front of us: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
What you get with us
- Anti-fungal sanitary silicone in wet areas
- We leave the area clean and tidy
- Old sealant always removed completely
- An ARBOMaster approved applicator
Take a look at what affects the cost and what customers say.
How we quote for new build mastic
Call for a quick quote. What matters most is:
- Any mould that needs treating
- Which sealant suits the joint
- The size of the job
- Any working-time requirements on site
No two jobs are quite the same, so each one gets its own quote. Size, access and the product the joint needs all make a difference.
Asking for a quote
What to tell us when you ask for a quote:
- A few photos by email, if you can
- If someone has resealed it before
- Whether it’s a home or a business
- Access, such as stairs, a lift or height
If you’re in New Charlton and need new build mastic, call 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and you’ll get a clear quote before work begins.
How to look after the new joints
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Watch for new gaps as the house dries out
- Use the extractor fan every time you shower
- Resist patching a failed seal with a tube from the DIY shop
- Report sealant problems to your builder during the snagging period
Wipe the sealant with warm soapy water. Keep scourers and harsh chemicals off it, which can damage the surface.
Lifting sealant traps moisture and mould behind it. Dealing with it before it goes black keeps the job straightforward.
How the job changes by surface
Windows and doors
A draught at a new window can be a missed or failed joint. We look at the joints and reseal where needed.
Show homes
Bathrooms, kitchens and frames in show homes are sealed or resealed to a neat finish. Tell us when the home is open so we can plan around it.
Also near New Charlton
Also in New Charlton
What happens on the day
The work is kept neat and contained to the area we’re working on, so you can get on with your day. Expect the work to take a few hours for most snagging lists, longer for a run of plots. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in New Charlton. A visitor permit or a nearby bay makes the visit run more smoothly.
- We go through the snagging list or plot schedule and agree the joints to do.
- We cut out every bit of the failed or messy sealant.
- Surfaces are cleaned of building dust and primed where needed.
- A sealant chosen for each area goes in and is tooled smooth.
- Each area is checked and left with its cure time.
Preparing for the visit
- Keep children and pets away from the work area
- Where the joints are inside, avoid wetting them before we arrive
- Mention if the joints have been sealed before
How to get a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and add photos by email if you can.
Read more
Work for landlords, hotels and businesses
For anyone letting property in or around New Charlton, several properties can go on one quote. Send us the addresses and the work at each.
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
Your questions about new build mastic in New Charlton
Is parking a problem for a job in New Charlton?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
Do you work for landlords with property near Charlton station?
Yes, we work for landlords and letting agents. Just phone 0345 464 0079 or email us and tell us about the property, and we will send you a clear quote.
Why has my new-build shower seal failed already?
Cracking in the first couple of years is common. Rushed application on dusty surfaces makes it worse.
Can I send you my snagging list?
Yes. Photos of each sealant item help us quote. If something is not sealant, we will say so.
Can you quote for more than one area?
Yes. Just list everything you need and we will quote it together.
Where are you based?
Mr Mastic is based in Crawley. We cover New Charlton and the rest of Greater London.
How do I get a quote for new build mastic in New Charlton?
We don’t publish prices, because the cost depends on the job: its size, the old material, access and the product needed. We agree the price before any work begins.
Should I wait before resealing?
It depends on whether water is getting through. Failed seals in wet areas need doing now, but cosmetic gaps can wait for movement to slow.
New homes and floors in New Charlton
Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Much of London’s new housing is flats in larger developments, where snags may need reporting through the developer or the managing agent.
As a London address, New Charlton can be tricky for parking: let us know about parking bays, permits or a driveway. For new homes near Charlton station, it’s worth checking the sealant early, while snags are still fresh.
New Charlton is about 2 miles north-east of Greenwich, in Greater London. Anywhere in SE7, our applicators can take on new build mastic. New Charlton is one of 764 towns and villages in Greater London we cover. We also work in London, about 6 miles from New Charlton.
All of SE7, SE18 and E16 is covered for new build mastic. If you need new build mastic at a property on Floyd Road, Priolo Road and Hasted Road or a nearby road, we can help. If you are just outside New Charlton, we cover Charlton (1 mile south-east), Westcombe Park (1 mile south-west), Woolwich (1 mile east), Vanbrugh Park Estate (1 mile south-west) and Maze Hill (2 miles south-west). Within a short drive, we also cover London (6 miles west), City of Westminster (8 miles west), Marylebone (8 miles west), Kensington (10 miles west), St Pancras (7 miles west) and Shoreditch (5 miles north-west).
Near you in New Charlton
In New Charlton, that means homes and buildings near Thames Barrier Park, Thorntree Primary School and The Victoria pub and the streets around them. There’s a railway station in New Charlton itself: Charlton station. Other landmarks nearby include Charlton Athletic Museum (within half a mile south) and Greenwich Castle (1.9 miles south-west). For a walk, there’s Gilbert's Pit.
Can I do it myself?
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.