Greater London · England
New Build Mastic in West Dulwich
New-build sealant joints in West Dulwich need attention? We cut out the old, prepare the joints and apply the right sealant, with a 12-month guarantee.
- Cracked sealant around new window and door frames
- Messy sealant that spoils new finishes
- Kitchen sealant that has pulled off the wall
How we handle new build mastic in West Dulwich
We work in new homes and on new-build sites across West Dulwich. Whether it’s one en suite or a run of plots, the method is the same: remove, clean, prime where needed, then a neat new bead. Typical jobs include gaps opening as the house dries out and settles and internal frame sealant that has split, across kitchens, bathrooms & en suites and skirting & floors.
Much of London’s new housing is flats in larger developments. In a new development, snags are often reported through the developer or the managing agent, and failed shower seals, open skirting joints and gaps at thresholds are typical.
All of our work is guaranteed for twelve months, in West Dulwich and everywhere else we cover.
- Place
- West Dulwich (SE21, SE27, SE19)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before work begins
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
New build mastic in West Dulwich: local notes
London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. Many of London’s new homes are flats in bigger developments, where snags may need reporting through the developer or the managing agent.
For new homes near Sydenham Hill station, it’s worth checking the sealant early, while snags are still fresh.
West Dulwich is about 1 mile north-east of West Norwood, in Greater London. Our applicators cover new build mastic for homeowners, landlords and businesses in West Dulwich. Across Greater London, we cover 764 places, West Dulwich among them.
Here we cover the SE21, SE27 and SE19 postcode area for new build mastic. Streets in the area include Berry Lane, Clive Road and Myton Road, all of which we cover. West Dulwich sits on or near the A2199. We also cover the places around West Dulwich: Sydenham Hill (1 mile east), West Norwood (1 mile south-west), Gipsy Hill (1 mile south), Dulwich (1 mile north) and Upper Norwood (1 mile south). Further out, we also cover London (5 miles north), City of Westminster (6 miles north-west), Marylebone (6 miles north-west), Kensington (7 miles north-west), St Pancras (7 miles north) and Shoreditch (6 miles north).
What’s near West Dulwich
In West Dulwich, that means homes and buildings near The Wood House, Dulwich Prep & Senior and Kingsdale Foundation School and the streets around them. There’s a railway station in West Dulwich itself: Sydenham Hill station. A little further out are British Vintage Wireless And Television Museum (under half a mile west) and St Christopher's Hospice (1.3 miles south-east). Not far away are Battersea Park Lake and Dulwich Upper Wood.
How the visit works
We keep the work tidy and contained to the joints we’re treating, so you can carry on as normal. Expect the work to take a few hours in a single home, and we tell you how long to leave it before we go. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in West Dulwich. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by going through the snagging items or plot schedule with you.
- Every bit of the old builder’s sealant is cut out.
- We clean out the dust and grit left from the build.
- We prime where needed and apply a sealant suited to each joint.
- We tool every joint neatly and tell you when each area can be used.
Before we arrive
- Keep children and pets away from the work area
- Move anything stored near the joints
- Mention any leaks or damp you’ve noticed
Getting a quote
To get a quote, call 0345 464 0079 or send us an email with the location and a short description of the problem. We will give you a clear quote before any work starts.
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Should I try it myself first?
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
A DIY attempt doesn’t rule out a professional job. We cut it out and start again, so just mention it when you contact us.
Why it’s worth doing now in West Dulwich
The builder is normally the first port of call while the snagging or warranty period runs. If it keeps failing or is not dealt with, we can reseal it properly. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler for homes in West Dulwich.
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs. Ask us for a quote and we’ll go through it with you.
Why choose Mr Mastic in West Dulwich
- Arbo and Everbuild products
- Homes, businesses and hotels
- ARBOMaster approved applicator
- Full insurance on every job
Take a look at how sealant jobs are priced or what customers say.
Also near West Dulwich
Also in West Dulwich
West Dulwich questions
Is parking a problem for a job in West Dulwich?
Parking in West Dulwich, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Is West Dulwich in your area for new build mastic?
Yes, West Dulwich is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or send us an email with a few details of the job.
What colour sealant will you use?
It depends on the joint: white or clear for most sanitary joints, colours for worktops, floors and frames. We agree the colour before we start.
How long should I leave it?
Many sealants skin over quickly but take longer to cure fully. We will tell you how long to leave the joint before we leave.
How long does new build mastic take?
Typically it takes a few hours for most snagging lists, longer for a run of plots. Bigger jobs take longer, and we’ll tell you how long to expect.
Are you an approved applicator?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
Can you work from my snagging list?
Yes. Send the list and a few photos of the sealant items. We will tell you if anything on it is not a sealant job.
Will the old sealant be removed?
Yes, always, and completely. New silicone does not stick to old silicone, so any old material comes out before anything new goes in.
Landlords, agents and businesses in West Dulwich
If you manage several properties in or around West Dulwich, several properties can be quoted together. Send us the addresses and the work at each, and pictures by email help.
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
When it isn’t the sealant
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Cracking that points to a structural problem
- Leaks from pipes, valves or wastes, which need a plumber
- Deciding who is responsible under a builder’s warranty
If in doubt, call 0345 464 0079 or send us an email and we will say what we think.
Surfaces we seal
- Windows & doors
- Kitchens
- Skirting & floors
- Plot handovers
- Bathrooms & en suites
- Show homes
Aftercare tips
A little care helps the new joints last. Our advice:
- Don’t seal over failed sealant yourself
- Watch for new gaps as the house dries out
- Raise failed sealant with the developer while you are covered
- Wait for the cure time before using a resealed shower
Keep an eye on the joints over the first couple of years. Small gaps can appear as the house dries and can be resealed later.
Leave a failed new-build seal and water can reach the floor and the ceiling below. Early resealing keeps the job small.
Common problems we fix in West Dulwich
Fresh sealant can be knocked or cut by trades finishing off. If it’s disturbed before curing, the joint can be left weak.
Common reasons people contact us include:
- Gaps between new skirting and floors
- Cracked sealant around new window and door frames
- Sealant that never bonded to the surface
- Plot mastic for developers ahead of handover
As a London address, West Dulwich can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
What to look for in a quote
- Which colour the sealant will be
- Whether the sealant suits the joint
- Who does the work, and how experienced they are
- What the cure time is