Greater London · England
West Dulwich External Mastic
Movement joints in West Dulwich need attention? We remove the old material, prepare the joints and seal them properly, with a 12-month guarantee.
- Old sealant gone brittle and cracked
- Damp patches traced to an open external joint
- Sealant pulling away from one side of the joint
External mastic in West Dulwich, done properly
External mastic is a job where short cuts show quickly. New sealant over old, joints packed with mortar and beads with no backing all tend to fail early. We strip the joint back and start again. If you’re dealing with hard, crazed mastic that has stopped moving and rain getting behind render or cladding at a joint, we can help, on brickwork movement joints, joints between brick and frames and copings & trims alike.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in West Dulwich, tell us how high the joints are and how to reach the back of the building.
Whatever the size of the job, you get the same one-year guarantee in West Dulwich and across Greater London.
- Where
- West Dulwich (SE21, SE27, SE19)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
What happens if it’s left?
Pointing a movement joint with mortar might seem a neat fix, but it locks the joint solid. The wall then cracks somewhere else. A flexible sealant over backing rod is what the joint needs. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in West Dulwich, the repair is bigger than a sealant job.
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether the work is at height. We take all of that into account in your quote.
Why us?
- A 12-month guarantee on all work
- More than 20 years in sealant work
- Experience in homes, commercial sites and hotels
- An ARBOMaster approved applicator
See our cost guide and what customers say.
Nearby places to West Dulwich
Also in West Dulwich
When it isn’t the sealant
It helps to know what we cannot do:
- Rising or penetrating damp from elsewhere in the wall
- Structural movement, which needs a surveyor or engineer
- Cutting new joints into brickwork, which is building work rather than sealant work
If you’re not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
What we seal
- Brickwork movement joints
- Concrete & block
- Render & cladding joints
- Joints between brick and frames
- Copings & trims
- Façade panels
How it works
Most of a good job is in the preparation, so that’s where we spend the time. Joints are cleaned back and dried before anything new goes in. In total, it usually takes a few hours to a few days, depending on the length of joint and the access. For a job in West Dulwich, parking and access are the things to plan: tell us about permits, visitor bays or off-street space, which floor we’re working on and whether there’s a lift.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- Mention any parking rules near the property
- Clear the area around the work
- Mention any sign-in or site rules at work premises
How to get a quote
Every job is quoted individually, so start by telling us what you need. Just call 0345 464 0079 or send us an email with the details, and pictures are welcome.
Advice
What the job involves on each surface
Cladding and façade panels
Where a cladding system has its own specified sealant, we follow it. Tell us what the building has when you get in touch.
Render joints
Water behind render can lead to blown patches. Resealing the joints early keeps water out and helps it last.
Can I do it myself?
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Keeping the joints in good condition
Aftercare is simple:
- Have failed joints looked at early
- Walk round the building once a year and look at the joints
- Check the sealant is paintable before painting near it
- Make sure movement joints are not pointed over
Only paint over the joint if we’ve confirmed the sealant can take paint. Many exterior sealants are not designed to be painted.
Once a joint can’t move, the wall finds another way, usually as cracking in the brickwork or render nearby. Catch it early and you reduce the risk.
What external mastic looks like in West Dulwich
Historic houses like Kingswood House (about 0.2 miles south) are a reminder that the area around West Dulwich has older buildings as well as new. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking.
For landlords with property near Sydenham Hill station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. For an older house near a landmark such as Church of St Stephen, older walls, gutters and the joints where extensions meet them need a flexible sealant. As a London address, West Dulwich can be tricky for parking: let us know about parking bays, permits or a driveway.
West Dulwich is about 1 mile north-east of West Norwood, in Greater London. Whether you’re in the middle of West Dulwich or further out, external mastic is available for homes and businesses alike. 764 places in Greater London are on our list, large and small.
Every address in SE21, SE27 and SE19 is covered for external mastic, from the main roads to the quietest streets. If you need external mastic at a property on Berry Lane, Clive Road and Myton Road or a nearby road, we can help. You’ll find West Dulwich on the A2199, which makes it straightforward to reach. We also cover 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
Locally, jobs take us to homes and businesses close to The Wood House, Dulwich Prep & Senior and Kingsdale Foundation School. West Dulwich has its own railway station: Sydenham Hill station. Well-known places in the area include British Vintage Wireless And Television Museum (less than half a mile west) and St Christopher's Hospice (1.3 miles south-east). Open spaces near West Dulwich include Battersea Park Lake and Dulwich Upper Wood.
FAQs for West Dulwich
Can you do external mastic in West Dulwich?
Yes. Our work covers London and the South East, and West Dulwich is part of that. You can call 0345 464 0079 or email us and let us know what needs doing.
Can you help a landlord with a rental near Sydenham Hill station?
Yes. We work for landlords and agents as well as homeowners. Just phone 0345 464 0079 or send us an email with the address and what needs doing, and we will give you a clear price.
Will the old sealant be removed?
Always. Sealing over the old bead is the commonest cause of early failure, and it’s something we never do.
What sealant do you use?
We choose the sealant for the joint, not the other way round. Movement, water and weather all affect the choice.
How do you reach high-level joints?
That depends on how high the joints are and the ground below. Low-level joints are straightforward; for higher work, tell us about the building and we will confirm what’s needed.
How long before the joint can be used?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used before we leave.
Is the work guaranteed?
Yes. Every job comes with our 12-month guarantee.
Do you have insurance?
Yes. We are fully insured, and we can confirm the details when we quote.
Landlords, agents and businesses in West Dulwich
Landlords and letting agents in West Dulwich can book us as well as householders. Sealant work between tenants keeps a property looking cared for.
We also work for property managers and facilities teams. We can quote a run of properties together.