Greater London · England
Highbury External Mastic
Our applicators work in Highbury on sealing brickwork movement joints, render, cladding and façade joints. Old material cut out, joints cleaned and sealed neatly and a 12-month guarantee.
- Weathered mastic that no longer stretches
- Joints with sealant missing in places
- Failed sealant between panels on a façade
Signs you need external mastic in Highbury
If plants are growing out of a joint, the sealant has generally failed or was never there. Dirt and roots then trap moisture in the joint and speed up the damage.
Signs it’s time to call us include:
- Brick movement joints where the sealant has split
- Failed seals between different materials
- Rigid filler in a joint that should flex
- Panel joints letting water in
If you look after a building such as Highbury Quadrant Primary School, larger buildings have long runs of movement joint that eventually need resealing.
What your quote should include
- When the joint can take water or movement
- Who turns up on the day
- What insurance they hold
- What happens if the job turns out different
External mastic in Highbury, done properly
Low-level joints can normally be done from the ground. For joints higher up, give us some details of the building and we’ll confirm what access is needed. Common call-outs are for hard, crazed mastic that has stopped moving and weeds or debris growing in open joints, across render & cladding joints, concrete & block and brickwork movement joints.
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. For a flat in Highbury, check the lease for who looks after the outside.
We stand behind the work with a 12-month guarantee.
- Where
- Highbury (N1, N16, N5)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
What external mastic looks like in Highbury
In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking. With historic houses such as Sutton House (about 2 miles east) nearby, there’s older building stock in the area around Highbury as well as newer homes. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth.
For an older house near a landmark such as Christ Church, older walls, gutters and the joints where extensions meet them need a flexible sealant. If you let a flat or house near Canonbury station, split movement joints are easy to miss on a rental until damp shows inside.
Highbury is about 4 miles north-east of City of Westminster, in Greater London. For external mastic in and around Highbury, please call 0345 464 0079 or send us an email for a quick quote. We’re based in Crawley and cover Greater London, Highbury included. Our Greater London coverage runs to 764 places, Highbury among them.
Our applicators cover all of N1, N16 and N5 for external mastic and the streets around it. If you need external mastic at a property on Prah Road, Dove Road and Lough Road or a nearby road, our applicators can take on the job. Highbury is on the A1199, which makes it straightforward to reach with everything needed for external mastic. Close by, we work in Newington Green (1 mile east), Mildmay (1 mile east), Canonbury (1 mile south-east), De Beauvoir Town (1 mile south-east) and Stoke Newington (1 mile north-east). Within a short drive, we also cover London (4 miles south), City of Westminster (4 miles south-west), Marylebone (3 miles south-west), Kensington (6 miles south-west), Walthamstow (4 miles north-east) and Whitechapel (3 miles south-east).
Near you in Highbury
Typical jobs here are in homes near Highbury Fields, Musical Theatre Academy and The Snooty Fox pub, among other places. Highbury has its own railway station: Canonbury station. Well-known places in the area include Arsenal Football Club Museum (0.6 miles north-west) and Montfichet's Tower (2.7 miles south). Not far away are Gillespie Park and Dartmouth Park Hill.
What affects the cost of external mastic
For a quick quote, just ask. The main things that affect it are:
- Whether the work is at height
- How much old sealant there is and how hard it is to remove
- Which sealant suits the joint
- Any mould that needs treating
Commercial jobs are quoted on the same basis as homes: how much there is to do, how we reach it and what it needs. Ask us for a quote and we’ll explain what it covers.
What to tell us for a quote
To help us quote quickly, please include:
- What the problem is, such as mould, gaps, leaks or cracking
- A few pictures by email, if you can
- Whether it has been sealed before
- Where the property is
Asking for a quote is easy: let us know the job and the location, and roughly how big it is. A few photos by email make the job easier to understand.
Towns and villages near Highbury
More services for Highbury
Why deal with it now?
Running new sealant over the old bead rarely lasts. New sealant doesn’t bond well to old, weathered sealant, so we always take the old sealant out. In a London flat, a failed joint rarely stays your problem alone: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Combining jobs into one visit generally makes better use of the time than several visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
Why book with us
- 20+ years of sealant experience
- Full insurance on every job
- We leave the area clean and tidy
- Every job guaranteed for a year
Take a look at what affects the cost or customer reviews.
Looking after it afterwards
Simple care keeps the joints in good condition. We recommend:
- Fix overflowing gutters above sealed joints
- Look over the joints every year, ideally after winter
- Check the sealant is paintable before painting near it
- Point out the joints to other trades
Follow the cure time we give you before the joint is knocked or disturbed. Most exterior sealants skin fast but take longer to cure right through.
If you can see gaps, plants or bare sections in a joint, have it checked. Early work is quicker and leaves a better finish.
Work for landlords, hotels and businesses
Hotels need rooms back in use, so we plan the work room by room. We’ve worked in hotels as well as homes and businesses.
For anyone letting property in or around Highbury, jobs at different addresses can go on one quote. Send us the addresses and the work at each, and photos by email help.
How it works
Most of a good job is in the preparation, and we do not rush it. Joints are cleaned back and dried before anything new goes in. All told, the work takes 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.
- We inspect the joints and agree which need resealing and how they’ll be reached.
- Old sealant and any debris are cut and raked out.
- The joint faces are cleaned and primed where the sealant needs it.
- We push in closed-cell backing rod so the sealant is the right depth and bonds to the sides only.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
Getting ready for the visit
- Try not to wet indoor joints just before the visit
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us if parking is tricky
Ask for a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we’ll explain how we’d tackle it. Whenever you are ready, phone 0345 464 0079 or send us an email.
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Highbury: your questions answered
Is parking a problem for a job in Highbury?
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.
Can you help a landlord with a rental near Canonbury station?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or email us with the address and a few details, and we’ll give you a fixed price before any work starts.
Do you take out the old sealant first?
Always. Sealing over the old bead is the commonest cause of early failure, and it’s something we never do.
What does external mastic cost?
There’s no set price, as it depends on the job: how much there is, what’s there now, how we reach it and what it needs. We agree the price before any work begins.
Is there a guarantee?
Yes: twelve months. If anything is not right with the work within the year, let us know and we will sort it.
When will the joints need doing again?
It varies from wall to wall: sunny, exposed elevations and busy joints wear faster. A yearly look will tell you when they need doing. Every job carries our 12-month guarantee.
Do you cover Highbury?
Yes. We cover Highbury, as part of our work across South East England, London and Scotland. To book, call 0345 464 0079 or drop us an email.
Can new sealant go over the old?
No. Fresh sealant does not stick to old sealant, and it traps any mould or water underneath. It all has to come out first.
What sealant work can’t fix
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Damp that is not coming from the joint
- Walls that need new movement joints cut into them
- Movement that’s more than a sealant joint can take
Not sure which it is? You can call 0345 464 0079 or email us and we’ll tell you honestly before you book.
Joints and surfaces we work on
- Façade panels
- Copings & trims
- Render & cladding joints
- Brickwork movement joints
- Concrete & block
- Joints between brick and frames