Greater London · England
External Mastic in Gunnersbury
External mastic for Gunnersbury, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Leaking joints around cladding and façade panels
- Weeds or debris growing in open joints
- Joints where the bead has come unstuck
What affects the quote in Gunnersbury
Some jobs are bigger than they look, and some smaller. The main factors:
- The number and length of the joints
- Whether old sealant or filler has to be cut out
- How many areas need sealing
- Whether the work is at height
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
What to tell us for a quote
You don’t need to know the technical terms. It helps if you can tell us:
- Where the job is, and your postcode
- Any access issues, like height or stairs
- Any previous sealing or DIY work
- Whether it’s a home or a business
To get a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You’ll have a clear quote before we start.
External mastic for homes and businesses in Gunnersbury
A movement joint is only as good as its depth. Backing rod controls how deep the sealant goes and keeps it off the back of the joint, so it bonds to the two sides only and can stretch. We work on copings & trims, joints between brick and frames and façade panels, and people most often call us about movement joints filled with mortar instead of sealant and gaps where render, brick and frames meet.
Modern London flats rely on sealed movement joints and cladding joints. Period houses have different weak points, such as gutter joints, trims and the line where an extension meets the old wall.
There’s a 12-month guarantee on every job.
- Location
- Gunnersbury (W4, W3, TW8)
- Region
- Greater London
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Why it’s worth doing now in Gunnersbury
It often makes sense to reseal all the failing joints on an elevation together. Joints of the same age tend to fail together, and access only has to be arranged once. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Gunnersbury, the repair is bigger than a sealant job.
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote.
Why choose Mr Mastic in Gunnersbury
- Approved under the ARBOMaster scheme
- Colour agreed with you before we start
- We leave the area clean and tidy
- Full insurance on every job
Take a look at our cost guide or our reviews.
Also near Gunnersbury
What else we do in Gunnersbury
How to look after the new joints
Simple care keeps the joints in good condition. We recommend:
- Don’t let climbing plants root in the sealant
- Act on the first splits you see
- Leave the joints unpainted unless we’ve said otherwise
- Walk round the building once a year and look at the joints
Do not paint over the new sealant unless we have said the product is paintable. Many exterior sealants aren’t designed to be painted and spoil the finish.
Once a joint cannot move, the wall finds another way, generally as cracking in the brickwork or render nearby. Resealing it early helps prevent that.
Gunnersbury: your questions answered
Can parking be tricky for a visit in Gunnersbury?
Parking in Gunnersbury, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Can you help a landlord with a rental near Gunnersbury station?
Yes. We work for landlords and letting agents as well as householders. You can ring 0345 464 0079 or send us an email with the details for a clear quote.
Can you reach joints on upper floors?
That depends on the building and the joints. We work on joints that can be reached safely. Give us some details and we will confirm the access.
Can you match the colour of my brickwork?
We choose a sealant colour to suit the brick, stone or render so the joint blends in. There’s a wide choice of exterior colours.
Can a movement joint be filled with mortar?
No. Rigid materials can’t move with the wall and the joint fails. If it has already been filled, we can generally cut it out and reseal it.
Will it make a mess?
Tidy work is part of the job. We protect what’s around the joints, and we clear up when we’re done.
What do you put in the joint?
The product depends on the job: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
What do you need from me for a quote?
A short description and the location, plus photos if you have them. We’ll ask anything else we need to know.
The process
Once we are on site, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. Most jobs then take anything from a few hours to several days, depending on the building. In Gunnersbury, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by walking round the building and agreeing the joints and the access.
- Every bit of old sealant and any mortar or debris is cut out.
- The faces are brushed clean and primed where the product requires it.
- We fit closed-cell backing rod to control the depth.
- The exterior sealant is applied, tooled and checked along its length.
How to prepare
- Mention any tricky access
- Mention any sign-in or site rules at work premises
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
We quote each job on its own, so start by telling us what you need. Simply call 0345 464 0079 or email us and describe the job and send pictures if you have them.
Advice
Work for landlords, hotels and businesses
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
We also work for property managers and facilities teams in Gunnersbury and across Greater London. Several sites can go on one quote, and we’re fully insured for the work.
External mastic in Gunnersbury: local notes
With historic houses such as Gunnersbury Park (about 0.7 miles north-west) nearby, there’s older building stock in the area around Gunnersbury 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. London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking.
As a London address, Gunnersbury can be tricky for parking: let us know about parking bays, permits or a driveway. If you live in an older home near St Michael's Church, an extension built onto an older house moves differently, and the joint between them takes the strain.
Gunnersbury is about 1 mile south of Acton, in Greater London. Whether you’re in the middle of Gunnersbury or further out, we cover external mastic for every kind of property. Our Greater London coverage runs to 764 places, Gunnersbury among them. There’s also a page for London, about 8 miles away.
Every address in W4, W3 and TW8 is within our area for external mastic. External mastic is available to properties on Kew Road, Kent Road and Power Road and the roads around them. You’ll find Gunnersbury on the A3000, which makes it straightforward to reach. Nearby, we also carry out external mastic in Strand-on-the-Green (1 mile south), Kew (1 mile south), Grove Park (1 mile south-east), Chiswick (1 mile east) and Turnham Green (1 mile south-east). Further out, we also cover London (8 miles east), City of Westminster (6 miles east), Marylebone (6 miles east), Kensington (3 miles east), St Pancras (7 miles east) and Shoreditch (9 miles east).
Local landmarks in Gunnersbury
Locally, jobs take us to homes and businesses close to Clayton Hotel Chiswick, Kew College Prep and Ark Acton Academy. Other local landmarks include Turnham Green (0.5 miles east) and Library for Iranian Studies (1 mile north). Gunnersbury has its own railway station: Gunnersbury station. Nearby you will also find Barnes Hospital (2 miles south-east) and Livat Hammersmith (2.1 miles east). Open spaces near Gunnersbury include Kew Gardens Lake and Castlebar Hill.
Common problems we fix in Gunnersbury
Buildings move more than people expect. Clay bricks expand slightly over their life, concrete and block shrink, and everything moves with temperature and wet. The sealant in the movement joints takes that strain.
These are the problems we are asked about most:
- Weathered mastic that no longer stretches
- Failed seals between different materials
- Moss and dirt in joints with no sealant left
- Failed sealant between panels on a façade
Rented homes near Gunnersbury station change hands often, and failed wall and movement joints let damp in, so they’re worth checking between tenancies.
Before you book anyone
- How the surfaces are prepared before sealing
- How long the guarantee is
- Is the old sealant removed completely?
- How long to leave it before use
Honest limits
We will always be straight with you, so here’s what new sealant will not do:
- Subsidence or other structural problems
- Walls that need new movement joints cut into them
- Render that’s blown, hollow or coming away
If you are not sure, just ring 0345 464 0079 or email us and we’ll give you a straight answer.
Joints and surfaces we work on
- Concrete & block
- Brickwork movement joints
- Copings & trims
- Render & cladding joints
- Façade panels
- Joints between brick and frames