Greater London · England
External Mastic in Brondesbury
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Brondesbury and across Greater London. Fully insured, ARBOMaster approved and guaranteed for a year.
- Sealant pulling away from one side of the joint
- Plants rooting in failed movement joints
- Rigid filler in a joint that should flex
How we handle external mastic in Brondesbury
A movement joint is only as good as its depth. Closed-cell backing rod sets the depth and stops the sealant sticking to the back, so it bonds to the two sides only and can stretch. If you have weathered mastic that no longer stretches and rain getting behind render or cladding at a joint, we can help, whatever the surface.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in Brondesbury, tell us how high the joints are and how to reach the back of the building.
Big or small, it’s backed by our 12-month guarantee in Brondesbury and across Greater London.
- Where
- Brondesbury (NW6, NW2, NW10)
- Region
- Greater London
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
How we quote for external mastic
There’s no set price list. What we look at:
- The size of the job
- When we can work, for business premises
- Any mould that needs treating
- Whether the work is at height
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs. Ask us for a quote and we’ll go through it with you.
Helping us quote
Photos help, but a description is a good start. Try to tell us:
- Whether it has been sealed before
- What’s wrong with the joints now
- A few pictures by email, if you can
- Roughly how big the job is
Every job is quoted individually. Just ring 0345 464 0079 or send us an email with the details.
Towns and villages near Brondesbury
More services for Brondesbury
How the visit works
There’s no need to move everything out, only the area right around the joints. We protect the rest, and the work takes a few hours to a few days, depending on the length of joint and the access for a typical job. 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.
- We start by walking round the building and agreeing the joints and the access.
- We cut out the old mastic and rake out anything in the joint.
- 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.
Preparing for the visit
- Plan for the work area to be out of bounds to pets and children
- Tell us about any previous sealing or DIY attempts
- Let us know if you’ve seen damp or leaks
Ask for a quote
Getting a quote is simple: let us know the job and the location and its rough size. Photos by email help us understand the job, and we’ll take it from there.
Advice
Why deal with it now?
Done well, a resealed joint is a neat, straight line that suits the wall. A rushed bead with no backing looks untidy and doesn’t last so it’s worth doing right. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble.
No two jobs are quite the same, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all make a difference.
Why book with us
- Any old sealant cut out fully, not covered over
- Anti-fungal silicone where joints get wet
- More than 20 years in sealant work
- Sealant colour chosen to suit
Brondesbury questions
Is Brondesbury in your area for external mastic?
Yes. We work across London and the South East, and Brondesbury is part of that. You can phone 0345 464 0079 or send us an email and tell us what needs doing.
Is parking a problem for a job in Brondesbury?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot.
What is backing rod for?
We fit closed-cell backing rod wherever the joint depth needs controlling. It controls the depth and stops the sealant bonding to the back.
How often do external joints need resealing?
There’s no fixed answer: sunny, exposed elevations and busy joints wear faster. Check them each year and reseal when they split or harden. Our work comes with a 12-month guarantee.
Do you have insurance?
Yes. We are fully insured, and we can confirm the details when we quote.
Do you take out the old sealant first?
Yes. All of the old material is cut out and the joint cleaned before resealing.
How much does external mastic cost in Brondesbury?
There’s no set price, as it depends on the job: its size, the old material, access and the product needed. You’ll get a clear quote before work begins.
Do the sealants smell?
Possibly a little. Any smell clears as the sealant cures.
What the job involves on each surface
Cladding and façade panels
Panels heat up and cool down quickly, so the joint sealant has to cope with frequent movement. We choose the product to suit.
Render joints
Cracks along render joints let water in behind the coat. A sound joint keeps the render dry behind.
Walls and rooflines in Brondesbury
London terraces and converted houses often share gutters, downpipes and walls, so it’s worth agreeing who is responsible before work starts. Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Letting a property close to Brondesbury station? Then split movement joints are easy to miss on a rental until damp shows inside. As a London address, Brondesbury can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. Schools such as North West London Jewish Day School are buildings too, and movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Brondesbury is about 1 mile north of Kilburn, in Greater London. Wherever you are in the NW6 postcode area, we cover external mastic for homes and businesses. We cover 764 towns and villages across Greater London, large and small. We also work in London, about 6 miles from Brondesbury.
All of NW6, NW2 and NW10 is within our area for external mastic. External mastic is available to properties on Dyne Road, Mill Lane and The Avenue. Brondesbury is on the A4003, so it’s easy for us to get to. We also cover Kilburn (1 mile south), Cricklewood (1 mile north-west), Queen's Park (1 mile south), Kensal Rise (1 mile south-west) and Willesden Green (1 mile west). Within a short drive, we also cover London (6 miles south-east), City of Westminster (3 miles south-east), Marylebone (3 miles south-east), Kensington (3 miles south), St Pancras (4 miles east) and Shoreditch (6 miles east).
Near you in Brondesbury
Locally, jobs take us to homes and businesses close to Black Lion pub, Kilburn Grange Park and Brondesbury College and the streets around them. Brondesbury has its own railway station: Brondesbury station. A little further out are New End Hospital (1.5 miles north-east) and Brent Museum and Archives (1 mile west). Open spaces near Brondesbury include Primrose Hill and Westbere Copse.
What sealant work can’t fix
It helps to know what we can’t do:
- Subsidence or other structural problems
- Adding movement joints to masonry that has none
- Cracked brickwork or render that needs a builder or plasterer
Not sure which it is? You can call 0345 464 0079 or send us an email and we’ll tell you honestly before you book.
Where we work in Brondesbury
- Façade panels
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
- Concrete & block
Should I try it myself first?
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Landlords, agents and businesses in Brondesbury
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
If you manage several properties in or around Brondesbury, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and pictures by email help.