Greater London · England
Brent Cross External Mastic
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Brent Cross and across Greater London. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Panel joints letting water in
- Gaps where render, brick and frames meet
- Damp patches traced to an open external joint
What we do, step by step
When we get to you, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. Most jobs then take a few hours for a handful of joints, longer for a whole elevation. In Brent Cross, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- 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.
- We gun in low-modulus sealant and tool it neatly.
Getting ready for the visit
- Let us know about earlier repairs to the joints
- Tell us about any water getting in
- Mention any parking rules near the property
How to get a quote
To get a quote, call 0345 464 0079 or email us with the location and a short description of the problem. We’ll send you a clear quote before any work starts.
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External mastic in Brent Cross
External mastic is a job where short cuts show quickly. New sealant over old, joints packed with mortar and beads with no backing rarely last long. We strip the joint back and start again. If you’re dealing with leaking joints around cladding and façade panels and moss and dirt in joints with no sealant left, we can help, whatever the surface.
London’s terraces and conversions often share walls, gutters and downpipes with their neighbours, so a leaking gutter joint or failed wall joint can affect more than one home. For a flat in Brent Cross, check the lease for who looks after the outside.
Our work is backed for twelve months, and the guarantee is the same wherever you are.
- Location
- Brent Cross (NW4, NW11, NW2)
- Region
- Greater London
- Cover
- One year on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
What sealant work can’t fix
To be straight with you, there are a few things sealant will not fix:
- Walls that need new movement joints cut into them
- Damp that isn’t coming from the joint
- Cracks in the bricks or render themselves, away from the joints
If you’re not sure, just phone 0345 464 0079 or drop us an email and we will give you a straight answer.
What we seal
- Copings & trims
- Façade panels
- Joints between brick and frames
- Render & cladding joints
- Brickwork movement joints
- Concrete & block
For landlords and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we will give you a quote.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
Your questions about external mastic in Brent Cross
I let a flat near Brent Cross West station. Can you help?
Yes, landlords and agents are among the people we work for. You can call 0345 464 0079 or email us with the details for a clear quote.
Can parking be tricky for a visit in Brent Cross?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
What do you put in the joint?
Quality sealants from brands including Arbo and Everbuild, picked for each joint. We’ll tell you what we’re using and why.
Why is there a gap in my brick wall?
It’s a deliberate gap that lets the wall expand and contract without cracking. It’s sealed with a flexible sealant, not mortar.
Can you do several jobs on one visit?
Yes. Several rooms, windows or areas can go on one quote.
How long will you be here?
Most jobs take a few hours to a few days, depending on the length of joint and the access, including the preparation. We will confirm how long when we quote.
How do I get a quote for external mastic in Brent Cross?
The cost depends on the size of the job, access and how much old sealant has to come out. Ask us for a quote and we will talk you through it.
Can you seal joints between two different materials?
Yes. Different materials move at different rates, so the joint between them must be flexible. We choose one that suits both surfaces.
Can I do it myself?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it does not work out, we can still put it right.
What we’re called out for in Brent Cross
Many joints fail because they were sealed too deep or with nothing behind them. Sealant bonded to three sides has nowhere to go and rips as the joint opens.
Keep an eye out for these signs:
- Joints pointed up with cement by mistake
- Movement joints with cracked, split or missing sealant
- Cracked joints where brick meets render or frames
- Damp patches traced to an open external joint
If you let a flat or house near Brent Cross West station, outside joints that have cracked can let damp into a rental, so check them between lets.
Comparing quotes
- What happens if the job turns out different
- How much experience the applicator has
- Whether the sealant suits the joint
- Is the old sealant removed completely?
What happens if it’s left?
The longer a joint stays open, the more water the wall takes in. Wet masonry is more easily damaged by frost, so the problem grows beyond the joint itself. In a flat in Brent Cross, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
What it costs depends on the size of the job, how much old material has to come out and access to the work. We give a clear quote before any work starts.
Why book with us
- Full insurance on every job
- Colour agreed with you before we start
- Sealant colour chosen to suit
- Every job guaranteed for a year
Take a look at our cost guide and our reviews.
Walls and rooflines in Brent Cross
The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Heath House (about 1.9 miles south-east) nearby, there’s older building stock in the area around Brent Cross as well as newer homes. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
In the older streets around Christ Church Hendon, older walls, gutters and the joints where extensions meet them need a flexible sealant. Brent Cross is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Brent Cross is about 2 miles north-west of West Hampstead, in Greater London. If you need external mastic in Brent Cross, it’s easy to get a quote: please call 0345 464 0079 or send us an email. We cover Greater London from our Crawley base, Brent Cross included. Our Greater London coverage runs to 764 places, and Brent Cross is one of them. You can also see our page for London, roughly 8 miles from Brent Cross.
We work across the NW4, NW11 and NW2 postcode area for external mastic. Local streets include Park Road, Graham Road and Elliot Road. Being close to the A41, Brent Cross is easy for our applicators to reach for external mastic. Close by, we work in Hendon (1 mile north), Staples Corner (1 mile south-west), The Burroughs (1 mile north-west), Dollis Hill (1 mile south-west) and The Hyde (1 mile west). Within a short drive, we also cover London (8 miles south-east), City of Westminster (5 miles south-east), Marylebone (5 miles south-east), Kensington (5 miles south), St Pancras (6 miles south-east) and Shoreditch (7 miles south-east).
Landmarks near Brent Cross
In Brent Cross, that means homes and buildings near Kisharon College, Hasmonean Primary School and The White Bear pub. Brent Cross’s nearest station is Brent Cross West station, roughly 0.7 miles south-west. Nearby you will also find St Andrew's Hospital (1.2 miles south-west) and Brent Cross Shopping Centre (under half a mile west). For a walk, there’s Darland's Lake and Parliament Hill.
Towns and villages near Brent Cross
Also in Brent Cross
Looking after it afterwards
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Leave the joints unpainted unless we’ve said otherwise
- Keep high-pressure jets off the joints
- Get split or bare joints resealed while the damage is small
- Keep water from gutters off the wall
Avoid pressure-washing straight into the joints. High-pressure water can lift the edges over time.
Leaks behind façade panels and render often go unseen. When it finally shows inside, the joint may have been open for years, so it’s worth resealing at the first signs.