Greater London · England
External Mastic in Canonbury
Movement joints in Canonbury need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Moss and dirt in joints with no sealant left
- Hard, crazed mastic that has stopped moving
- Joints with sealant missing in places
External mastic in Canonbury, done properly
Ground-floor and low-level joints are straightforward to reach. For joints higher up, give us some details of the building and we will confirm what’s needed to reach them safely. Typical jobs include hard, crazed mastic that has stopped moving and movement joints with cracked, split or missing sealant, on joints between brick and frames, concrete & block and façade panels.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in Canonbury, tell us how high the joints are and how to reach the back of the building.
Your job is guaranteed for a year, as with all our work.
- Where
- Canonbury (N1, N1P, E8)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What sealant work cannot fix
A few problems are outside what sealant work can do:
- Loose or hollow render, which needs re-rendering
- Cutting new joints into brickwork, which is building work rather than sealant work
- Cracks in the bricks or render themselves, away from the joints
If you’re not sure, just phone 0345 464 0079 or send us an email and we’ll give you a straight answer.
Joints and surfaces we work on
- Façade panels
- Concrete & block
- Copings & trims
- Render & cladding joints
- Joints between brick and frames
- Brickwork movement joints
Canonbury buildings and the weather
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Sutton House (about 1.7 miles east) are a reminder that the area around Canonbury has older buildings as well as new. Where a home is older, older brick and stone need a sealant that suits them, at the right joint depth.
For site and facilities teams at buildings such as Rotherfield Primary School, its movement joints, gutters and trims need looking after like any other building’s. For an older house near a landmark such as St Paul's Church, the joints between older walls, newer extensions and the roofline need a sealant that can move.
Canonbury is about 2 miles north-east of St Pancras, in Greater London. If you need external mastic in Canonbury, it’s easy to get a quote: please call 0345 464 0079 or drop us an email. We’re based in Crawley and cover Greater London. Across Greater London, we cover 764 places, Canonbury among them.
Here we cover the N1, N1P and E8 postcode area for external mastic. Local streets include Dove Road, Essex Road and Clare Lane. Canonbury is on the A1199 and A1200, so it’s easy for us to get to with everything needed for external mastic. Other places close to Canonbury include De Beauvoir Town (1 mile east), Mildmay (1 mile north-east), Kingsland (1 mile east), Newington Green (1 mile north) and Highbury (1 mile north-west). Further out, we also cover London (3 miles south), City of Westminster (3 miles south-west), Marylebone (3 miles south-west), Kensington (6 miles south-west), Walthamstow (4 miles north-east) and Hampstead (4 miles west).
Near you in Canonbury
Around Canonbury, our work takes us to homes and buildings near Bishopsgate Institute Special Collections and Archives, City of London Academy Highbury Grove and Islington Green School, among other places. Other local landmarks include New Crown pub (under half a mile north-west) and Shoreditch Park (0.6 miles south). There’s a railway station in Canonbury itself: Canonbury station. Nearby you will also find Montfichet's Tower (2.2 miles south) and Clowns Gallery-Museum (0.7 miles east). For a walk, there’s St. James's Park Lake and Ludgate Hill.
Leave it or put it right?
An open joint keeps letting water into the wall with every downpour. In cold weather, frost can damage wet brick and render, so the damage spreads beyond the joint. In a flat in Canonbury, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
A failed joint rarely gets cheaper to fix by waiting. If you’re unsure, phone 0345 464 0079 or send us an email for an honest opinion and a quote.
Why Canonbury customers choose us
- Quality sealants from Arbo and Everbuild
- A 12-month guarantee on all work
- Fully insured
- Colour agreed with you before any work starts
See what affects the cost and what customers say.
What we are called out for in Canonbury
Some movement joints have been pointed up with mortar, often by someone who didn’t know what it was for. With the joint locked solid, the movement turns into cracks elsewhere in the wall.
Most people get in touch when they notice something like this:
- Brick movement joints where the sealant has split
- Hard, crazed mastic that has stopped moving
- Damp patches traced to an open external joint
- Moss and dirt in joints with no sealant left
As a London address, Canonbury can be tricky for parking: let us know about parking bays, permits or a driveway.
What to look for in a quote
- What the quote includes, VAT included or not
- Which sealant they’ll use, and why
- Whether they’re fully insured
- Whether you can choose the colour
Landlords, agents and businesses in Canonbury
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
What affects the cost of external mastic
Jobs vary more than people expect. What affects the quote:
- The number of rooms or windows
- The size of the job
- Any working-time requirements on site
- The type of sealant required
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs, plus any working-time requirements on site. Ask us for a quote and we will go through it with you.
What we need to know
To help us quote quickly, let us know:
- Whether it has been sealed before
- If it’s domestic, commercial or a hotel
- Any access issues, like height or stairs
- Where the property is
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we’ll explain how we’d tackle it. When it suits you, ring 0345 464 0079 or email us.
Surface by surface
Concrete and blockwork
Concrete faces can be dusty and porous, so preparation is key. A primer goes on where the product requires one before the bead.
Cladding and façade panels
Panels heat up and cool down quickly, so the joint sealant has to cope with frequent movement. The sealant is chosen with that in mind.
The process
At the end, we look at the finished work together and explain the cure time. The visit itself usually takes a few hours to a few days, depending on the length of joint and the access, depending on how much there is to do. For a job in Canonbury, parking and access are the things to plan: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- 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.
- 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
- Clear the area around the work
- For indoor joints, keep the area dry beforehand if you can
- Mention any sign-in or site rules at work premises
Ask for a quote
For a quick quote, get us on the phone, or email us if that’s easier. Describe what needs sealing and we’ll talk you through the work before giving you a price.
Related advice
Your questions about external mastic in Canonbury
Do you cover Canonbury for external mastic?
Yes. Our work covers London and the South East, and Canonbury is part of that. You can call 0345 464 0079 or email us and tell us what needs doing.
Is parking an issue for external mastic in Canonbury?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Can you seal joints between two different materials?
Yes. We cut out the old sealant, prepare both faces and reseal with a flexible exterior product. The colour is chosen to suit.
Do I have to be there?
That depends on where the joints are. For work indoors, someone needs to let us in, and for outside work we will agree access with you when we book.
How long does external mastic take?
That depends on how much there is to do, but most jobs take a few hours for a handful of joints, longer for a whole elevation. We will give you a better idea when we quote.
How do I get a quote for external mastic in Canonbury?
Every job is different, so each one gets its own quote. To get one, call 0345 464 0079 or email us with a short description of the job.
How do you reach high-level joints?
That depends on the building and the joints. We work on joints that can be reached safely. Give us some details and we’ll confirm the access.
What sealant do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. We use products from Arbo and Everbuild.