Greater London · England
St Ann's External Mastic
Professional external mastic in and around St Ann's, with old sealant always removed completely and a 12-month guarantee.
- Rigid filler in a joint that should flex
- Joints where the bead has come unstuck
- Cracked joints where brick meets render or frames
External mastic in St Ann's, done properly
As ARBOMaster approved applicators, we choose exterior sealants to suit the joint and the surfaces. Some surfaces need a primer before sealing, and we don’t skip that step. We work on façade panels, joints between brick and frames and copings & trims, and common reasons people get in touch are failed seals between different materials and joints where the bead has come unstuck.
Modern London flats rely on sealed movement joints and cladding joints. Older terraces have their own weak points: gutter joints, roofline trims and the joint where an extension meets the original wall, and both kinds of building are found across London.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we will sort it.
- Place
- St Ann's (N15, N4, N16)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
How to look after the new joints
No joint lasts for ever, but care makes a real difference. A few tips:
- Leave the joints unpainted unless we have said otherwise
- Check external joints each spring
- Avoid pressure-washing directly into sealant joints
- Clear growth from the base of walls and joints
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.
Act while the splits are small. At that stage it’s a simple cut out and reseal before water has had years to get in.
Walls and rooflines in St Ann's
Historic houses like Bruce Castle (about 1.3 miles north) are a reminder that the area around St Ann's has older buildings as well as new. In older buildings, older brick and stone need a sealant that suits them, at the right joint depth. 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.
St Ann's is in London, so parking needs planning: let us know about parking bays, permits or a driveway. For landlords with property near Seven Sisters station, split movement joints are easy to miss on a rental until damp shows inside. In the older streets around St Ann's Church, an extension built onto an older house moves differently, and the joint between them takes the strain.
St Ann's is about 2 miles north-west of West Hackney, in Greater London. Across the N15 area, we can carry out external mastic at your property. Our Greater London coverage runs to 764 places, St Ann's among them. There’s also a page for London, about 6 miles away.
Postcode districts we cover here for external mastic: N15, N4 and N16. You’ll find streets such as Ida Road, Elmar Road and Grove Road, and we cover them all. Neighbouring places we cover for external mastic include West Green (1 mile north-west), Seven Sisters (1 mile east), South Tottenham (1 mile east), Harringay (1 mile west) and Tottenham Green (1 mile north-east). Further out, we also cover London (6 miles south), City of Westminster (5 miles south-west), Marylebone (5 miles south-west), Kensington (8 miles south-west), St Pancras (4 miles south) and Shoreditch (4 miles south).
Near you in St Ann's
Locally, jobs take us to homes and businesses close to Church of St Andrew, No.8 Seven Sisters pub and Moselle Upper School and the streets around them. You will also find Chestnuts Park (less than half a mile west) and Park View School (0.5 miles north-west). There’s a railway station in St Ann's itself: Seven Sisters station. Well-known places in the area include City of London Maternity Hospital (1.7 miles south-west) and The Mall Wood Green (1.4 miles north-west). Open spaces near St Ann's include Railway Fields and Hollow Pond.
Landlord and commercial work in St Ann's
Landlords and letting agents in St Ann's can book us as well as homeowners. Sealant work between tenants is a simple way to keep a property in good order before the next move-in.
Housing providers, facilities teams and property managers book us too in St Ann's and across Greater London. Several sites can go on one quote, and we are fully insured for the work.
Also near St Ann's
Also in St Ann's
When something else is needed
Some problems need a builder, plumber or other trade rather than us:
- Structural movement, which needs a surveyor or engineer
- Walls that need new movement joints cut into them
- Cracked brickwork or render that needs a builder or plasterer
If in doubt, call 0345 464 0079 or email us and we’ll say what we think.
What we seal
- Brickwork movement joints
- Render & cladding joints
- Façade panels
- Concrete & block
- Joints between brick and frames
- Copings & trims
Should I try it myself first?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and getting the depth right matters as much as the look.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
What affects the cost of external mastic
There’s no set price list, because jobs vary so much. What we look at:
- Any working-time requirements on site
- The number of rooms or windows
- The old material and how stubborn it is
- Whether the work is at height
Leaving a failed joint usually makes the job bigger, not smaller, as water and mould keep getting in. If you’re not sure whether it needs doing, call 0345 464 0079 or drop us an email for an honest opinion and a quote.
Asking for a quote
When you contact us, these details help:
- The rough size of the job
- What’s wrong with the joints now
- Pictures of the joints, sent by email
- The address or postcode of the job
Every job is quoted individually, so start by telling us what you need. Simply phone 0345 464 0079 or drop us an email and describe the job and send pictures if you have them.
How the job changes by surface
Cladding and façade panels
Panel systems often rely on sealant between and around the panels. Each joint gets a sealant that suits the panel and its movement.
Render joints
Cracks along render joints let water in behind the coat. Resealing the joints early keeps water out.
St Ann's: your questions answered
Can you do external mastic in St Ann's?
Yes. Our work covers London and the South East, and St Ann's is part of that. You can phone 0345 464 0079 or drop us an email and tell us what needs doing.
Can parking be tricky for a visit in St Ann's?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Why do you put foam in the joint first?
The foam is closed-cell backing rod. It keeps the sealant at the right depth and bonded to the sides only, which would stop it stretching.
Can you seal joints between two different materials?
Yes. The old joint is removed, both surfaces cleaned and primed where needed, and a flexible sealant applied. We pick a colour that works with both materials.
When will the joints need doing again?
There’s no fixed answer: joints on exposed walls or with a lot of movement age sooner. A yearly look will tell you when they need doing. Our work comes with a 12-month guarantee.
I’m a tenant. Can you help?
Of course. Ask your landlord first, and we can send them the quote if that helps.
Are you ARBOMaster approved?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
How long does the job take?
Typically it takes a few hours for a handful of joints, longer for a whole elevation. Bigger jobs take longer, and we will tell you how long to expect.
The process
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 in most cases. In St Ann's, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.
- We start by checking each joint, agreeing the ones to redo and how we’ll reach them.
- We cut out the failed sealant and rake out any dirt or growth.
- The joint faces are cleaned and primed where the sealant needs it.
- Closed-cell backing rod is fitted to set the depth and stop three-sided bonding.
- We gun in a flexible exterior sealant in a colour that suits the wall and tool it neatly.
How to prepare
- Let us know about parking restrictions
- Keep children and pets away from the work area
- Where the joints are inside, avoid wetting them before we arrive
Ask for a quote
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we’ll talk you through the work.