Greater London · England
External Mastic in Barnes
Sealing brickwork movement joints, render, cladding and façade joints for Barnes, backed by a one-year guarantee. Ask us for a quote.
- Failed sealant between panels on a façade
- Hard, crazed mastic that has stopped moving
- Damp patches traced to an open external joint
Keeping the joints in good condition
Good habits help new joints last longer. Our tips:
- Wash walls gently around the sealant
- Leave the joints unpainted unless we’ve said otherwise
- Act on the first splits you see
- Check external joints each spring
Avoid pressure-washing straight into the joints. High-pressure water can lift the edges.
Small splits are the time to act. At that stage it’s a simple cut out and reseal with no damage behind it to deal with.
External mastic in Barnes, done properly
A movement joint is a deliberate break that lets a wall expand and contract. The sealant in it has to stretch and squeeze for years, so once it splits or hardens, the joint stops working and water gets in. We work on joints between brick and frames, façade panels and concrete & block, and common reasons people get in touch are joints where the bead has come unstuck and joints pointed up with cement by mistake.
Newer London blocks are built with movement joints in brick and render, and with cladding joints sealed with mastic. Period houses have different weak points, such as gutter joints, trims and the line where an extension meets the old wall, and both kinds of building are found across London.
All of our work is guaranteed for twelve months, and the guarantee is the same wherever you are.
- Place
- Barnes (SW13, SW15, SW14)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Barnes questions
Do you cover Barnes for external mastic?
Yes, Barnes is within the area we cover. Our work covers London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing, and we will give you a clear quote.
Can you help a landlord with a rental near Barnes Bridge station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. Just phone 0345 464 0079 or send us an email with the address and what needs doing, and we’ll give you a clear quote.
Is it OK to seal over old sealant?
No. The old sealant always comes out first, so the new sealant bonds properly.
Is the work guaranteed?
Yes: twelve months. If anything is not right with the work within the year, let us know and we will sort it.
What do you need from me for a quote?
A short description and the location, with pictures by email if possible. If we need more, we’ll ask.
How long does external mastic take?
A typical job takes a few hours for a handful of joints, longer for a whole elevation, including the preparation. Your quote will say how long we expect yours to take.
Do I have to be there?
Access is agreed with you when the job is booked. Indoors, that normally means someone at home.
How long does external mastic last?
It varies with how exposed the wall is and how much the joint moves. Signs to watch for are cracking, hardening and gaps at the edges.
Leave it or put it right?
Running new sealant over the old bead rarely lasts. The new layer can’t bond properly to old, weathered material, so the old joint is cut out fully first. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and by the time it shows on a wall or ceiling in Barnes, the repair is bigger than the sealant job would have been.
Doing several joints on one visit is normally more efficient than separate visits. We will give you a clear quote for the lot.
Why book with us
- Sealant colour chosen to suit
- A choice of colours where the product allows
- Approved under the ARBOMaster scheme
- Full insurance on every job
See our cost guide or what customers say.
What sealant work can’t fix
A few problems are outside what sealant work can do:
- Damp that isn’t coming from the joint
- Render that’s blown, hollow or coming away
- Movement that’s more than a sealant joint can take
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think.
Where we work in Barnes
- Brickwork movement joints
- Joints between brick and frames
- Concrete & block
- Render & cladding joints
- Copings & trims
- Façade panels
What happens on the day
When we arrive, we start by going over the job with you, so there are no surprises. Surfaces next to the work are protected before any work begins. Most jobs take a few hours to a few days, depending on the length of joint and the access. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. Mention any building rules, key holders or managing agents when you book.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- We fit closed-cell backing rod to control the depth.
- We apply the sealant, tool it and check the whole run.
How to prepare
- Tell us about any previous sealing or DIY attempts
- For business premises, tell us about site rules or sign-in
- Move anything stored near the joints
How to get a quote
Asking for a quote is easy: let us know what needs doing and where, and roughly how big it is. Photos by email help us understand the job.
Advice
Outside joints around Barnes
With historic houses such as Chiswick House (about 0.9 miles north-west) nearby, there’s older building stock in the area around Barnes as well as newer homes. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material. Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
If you let a flat or house near Barnes Bridge station, failed wall and movement joints let damp in, so they’re worth checking between tenancies. As a London address, Barnes can be tricky for parking: let us know about parking bays, permits or a driveway.
Barnes is about 2 miles west of Fulham, in Greater London. Every kind of property in Barnes can book us for external mastic, old or new, large or small. Every job comes with our one-year guarantee. Barnes is one of 764 places in Greater London we cover for external mastic. There’s also a page for London, about 7 miles away.
Here we cover the SW13, SW15 and SW14 postcode area for external mastic. We cover properties on Church Road, Station Road and Barnes High Street. You’ll find Barnes on the A306 and B349, so it’s easy for us to get to. Neighbouring places we cover for external mastic include Old Chiswick (1 mile north), Turnham Green (1 mile north-west), Mortlake (1 mile south-west), East Sheen (1 mile south-west) and Putney (1 mile south-east). We also work in nearby towns such as London (7 miles east), City of Westminster (5 miles north-east), Marylebone (5 miles north-east), Kensington (3 miles north-east), St Pancras (7 miles north-east) and Shoreditch (8 miles north-east).
Local landmarks in Barnes
In Barnes, that means homes and buildings near Chiswick School, Sun Inn and Barn Elms and the streets around them. Nearby too are Polish Library POSK in London (1.4 miles north) and The Harrodian School (0.6 miles north). There’s a railway station in Barnes itself: Barnes Bridge station. Other landmarks nearby include Barnes Hospital (0.7 miles south-west) and Putney Exchange (1.4 miles south-east). For a walk, there’s Richmond Hill and Kew Gardens Lake.
Common problems we fix in Barnes
UV, rain and frost all age exterior sealant. Over the years it hardens, cracks on the surface and loses its give, so the next time the wall moves, it splits or pulls away.
If you can see any of these, it’s time to have the joints looked at:
- Failed seals between different materials
- Brick movement joints where the sealant has split
- Failed sealant between panels on a façade
- Damp patches traced to an open external joint
Homes close to Barnes Methodist Church include some older properties, and old and new materials meet at the roofline and walls, which is where sealant earns its keep.
What your quote should include
- What happens if they find a problem under the old sealant
- What product goes in the joint
- Is VAT in the price?
- Whether they’re fully insured
Other services in Barnes
Landlord and commercial work in Barnes
Landlords and agents in Barnes can book us as well as homeowners. Sealant work between tenants keeps a property looking cared for.
We regularly work with letting and managing agents. Tell us the address, the job and how access works and we will give you a quote.
How we quote for external mastic
For a quick quote, just ask. The main things that affect it are:
- How much old sealant there is and how hard it is to remove
- Any working-time requirements on site
- Any mould that needs treating
- Access and height
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 to tell us for a quote
To help us quote quickly, let us know:
- If it’s domestic, commercial or a hotel
- How we’d reach the joints
- How many joints, rooms or windows are involved
- Any previous sealing or DIY work
We don’t publish a price list, as no two jobs are quite the same. Instead, we give you a clear price for your job. To arrange one, call 0345 464 0079 or send us an email.