Greater London · England
External Mastic in North Sheen
Our applicators work in North Sheen on sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly and a 12-month guarantee.
- Weeds or debris growing in open joints
- Failed seals between different materials
- Hard, crazed mastic that has stopped moving
About our external mastic in North Sheen
Joints between dissimilar materials, like brick against render or concrete against a steel frame, see movement from both sides. A flexible sealant bridges the two where mortar or filler would crack. If you have joints where the bead has come unstuck and rain getting behind render or cladding at a joint, we can help, on concrete & block, joints between brick and frames and façade panels alike.
London’s terraces and conversions often share walls, gutters and downpipes with their neighbours, so one failed joint can cause damp for more than one household. In a converted house in North Sheen, it’s worth checking who is responsible for the outside before booking.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Place
- North Sheen (TW9, SW14, W4)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear price before work begins
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What affects the cost of external mastic
The price is agreed before any work begins. It takes into account:
- The number and length of the joints
- How much old sealant there is and how hard it is to remove
- The type of sealant required
- Access and height
The cost depends on how much there is to do, how hard the old material is to remove and how easy the joints are to reach. We give a clear quote before we start, so you know where you stand.
Helping us quote
To help us quote quickly, please include:
- Where the property is
- If it’s domestic, commercial or a hotel
- Whether it has been sealed before
- How many joints, rooms or windows are involved
For a quote, ring 0345 464 0079 or send us an email with the location and a short description of the problem. We will send you a clear quote before any work starts.
Also near North Sheen
Also in North Sheen
What the job involves on each surface
Copings and trims
A failed coping joint lets water into the top of the wall. Sealing them early saves the wall below.
Render joints
Render is weaker at the surface than brick, so a sealant that stretches easily protects the edges. We prime where the product needs it.
Common questions in North Sheen
Is parking an issue for external mastic in North Sheen?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot.
Do you cover North Sheen for external mastic?
Yes. We work across London and the South East, and North Sheen is part of that. You can phone 0345 464 0079 or email us and let us know what needs doing.
Is it OK to fill a movement joint with cement?
No, not where the gap is a movement joint. Pointing it stops it working and can lead to cracking. A flexible sealant is the right fill.
Where are you based?
We work from Crawley. Our applicators cover North Sheen, along with the rest of our area.
Which products do you use?
Each joint gets the product that suits it. Where it moves, gets wet or faces the weather makes a difference, and we’ll explain our choice.
Can landlords and businesses book you?
Yes. We work for householders, landlords, letting agents, businesses and hotels in North Sheen.
Do you take out the old sealant first?
Yes. Sealing over the old bead is the commonest cause of early failure, and it’s something we never do.
Do the sealants smell?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.
North Sheen buildings and the weather
In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Managing a site like Kew Riverside Primary School? Then movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. If you live in an older home near The Barn Church, an extension built onto an older house moves differently, and the joint between them takes the strain. As a London address, North Sheen can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
North Sheen is about 3 miles south of Acton, in Greater London. Every kind of property in North Sheen is covered for external mastic, old or new, large or small. The work is guaranteed for a year. North Sheen is one of 764 places in Greater London where we work. There’s also a page for London, about 8 miles away.
Every address in TW9, SW14 and W4 is covered for external mastic, from the main roads to the quietest streets. External mastic is available to properties on Kent Road, Ibis Lane and The Avenue. We also cover the places around North Sheen: Kew (1 mile north), Grove Park (1 mile north-east), Strand-on-the-Green (1 mile north), East Sheen (1 mile south-east) and Mortlake (1 mile south-east). Larger places within reach include London (8 miles east), City of Westminster (6 miles north-east), Marylebone (6 miles north-east), Kensington (4 miles north-east), St Pancras (8 miles north-east) and Shoreditch (9 miles east).
Around North Sheen
In North Sheen, that means homes and buildings near Kew College Prep, Dukes Meadows and Chiswick School and the streets around them. There’s a railway station in North Sheen itself: Kew Gardens station. Well-known places in the area include Barnes Hospital (1.1 miles south-east) and Livat Hammersmith (2.5 miles north-east). Open spaces near North Sheen include Kew Gardens Lake and Duke's Hollow.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. Our tips:
- Get split or bare joints resealed while the damage is small
- Make sure movement joints are not pointed over
- Clear growth from the base of walls and joints
- Walk round the building once a year and look at the joints
Keep the joints clear of soil, plants and climbing growth. Damp material against the sealant shortens its life.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage, all bigger jobs than a reseal.
DIY versus a professional finish
A DIY attempt doesn’t rule out a professional job. We cut it out and start again.
What a professional job adds is preparation and the right 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.
What we cannot put right
We’ll always be straight with you, so here’s what new sealant won’t do:
- Movement that is more than a sealant joint can take
- Cutting new joints into brickwork, which is building work rather than sealant work
- Cracked brickwork or render that needs a builder or plasterer
If in doubt, ring 0345 464 0079 or send us an email and we will say what we think before booking.
Where we work in North Sheen
- Concrete & block
- Copings & trims
- Façade panels
- Joints between brick and frames
- Render & cladding joints
- Brickwork movement joints
How the visit works
We bring everything the job needs with us, so you do not need to buy or prepare anything. Once we’ve agreed what’s being done, the area is protected and the work begins. Most jobs take anything from a few hours to several days, depending on the building. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in North Sheen. It helps if you can point us to a visitor permit or a bay close to the door.
- 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
- Mention any sign-in or site rules at work premises
- Let us know if you’ve seen damp or leaks
How to get a quote
We quote each job on its own. Just call 0345 464 0079 or send us an email with the details and send photos if you have them.
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Why it’s worth doing now in North Sheen
The longer a joint stays open, the more water the wall takes in. In cold weather, frost can damage wet brick and render, so the problem grows beyond the joint itself. Damp from a failed joint spreads quietly in older London brickwork and timber, and by the time it shows on a wall or ceiling in North Sheen, the repair is bigger than the sealant job would have been.
Every job is a little different, so we quote each one individually. Size, access and the product the joint needs all make a difference.
What you get with us
- We’re fully insured
- Every job guaranteed for a year
- We agree the colour with you first
- We leave the area clean and tidy