Greater London · England
External Mastic in Chalk Farm
Movement joints in Chalk Farm need attention? We remove the old material, prepare the joints and seal them properly, and the work is guaranteed for a year.
- Movement joints filled with mortar instead of sealant
- Brick movement joints where the sealant has split
- Weeds or debris growing in open joints
Landlord and commercial work in Chalk Farm
Landlords and agents in Chalk Farm can book us as well as householders. Sealant work between tenants is a simple way to keep a property in good order.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
About our external mastic in Chalk Farm
We’re ARBOMaster approved applicators, and each external joint gets a sealant suited to it. Some surfaces need a primer before sealing. If you have panel joints letting water in and damp patches traced to an open external joint, we can put it right, whatever the surface.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. In Chalk Farm, joints up high may need ladders or other access, which is worth talking through when you book.
Our work is backed for twelve months, and the guarantee is the same wherever you are.
- Place
- Chalk Farm (NW5, NW1, NW3)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
What we do, step by step
There isn’t much for you to do on the day. Point us to the joints and we’ll get on with it. The work itself takes a few hours to a few days, depending on the length of joint and the access. In a London area like Chalk Farm, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- We look at every joint and agree a colour to suit the wall.
- Failed sealant is removed back to clean, sound faces.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- Primer is applied wherever the sealant needs it.
- We gun in low-modulus sealant and tool it neatly.
Before we arrive
- Tell us if parking is tricky
- For indoor joints, keep the area dry beforehand if you can
- Tell us about any previous sealing or DIY attempts
Getting a quote
We quote each job on its own. Just call 0345 464 0079 or drop us an email with the details and send photos if you have them.
Related advice
DIY versus a professional finish
If you are set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it doesn’t work out, we can still put it right.
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
What external mastic looks like in Chalk Farm
Historic houses like Winfield House (about 1.1 miles south-west) are a reminder that the area around Chalk Farm has older buildings as well as new. Where a home is older, older walls and rooflines need a sealant that moves with them and suits the material. 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.
If you let a flat or house near Kentish Town West station, outside joints that have cracked can let damp into a rental, so check them between lets. If you live in an older home near St Silas Church, the joints between older walls, newer extensions and the roofline need a sealant that can move.
Chalk Farm is about 1 mile south-east of Hampstead, in Greater London. From the centre of Chalk Farm to the outskirts, external mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Our area takes in 764 places across Greater London.
Every address in NW5, NW1 and NW3 is covered for external mastic, from the main roads to the quietest streets. That includes homes and businesses on Eton Road, Oval Road and Regal Lane and the roads around them. You’ll find Chalk Farm on the A5205, so it’s easy for us to get to with everything needed for external mastic. Other places close to Chalk Farm include Kentish Town (1 mile east), Primrose Hill (1 mile south-west), Haverstock (1 mile west), Belsize Park (1 mile west) and Camden Town (1 mile south-east). Within a short drive, we also cover London (4 miles south-east), Kensington (4 miles south-west), Shoreditch (3 miles east), Walthamstow (6 miles north-east), Hoxton (3 miles east) and Whitechapel (4 miles south-east).
Local landmarks in Chalk Farm
Typical jobs here are in homes near Primrose Hill, Cecil Sharp House and The Fiddlers Elbow Public House. Other local landmarks include Holy Trinity and Saint Silas CofE Primary School (less than half a mile east) and North Bridge House School (0.5 miles south-east). Chalk Farm has its own railway station: Kentish Town West station. A little further out are Isokon Gallery (0.7 miles north-west) and O2 Centre (1.3 miles west). The countryside around Chalk Farm includes Primrose Hill and The Long Water.
FAQs for Chalk Farm
Can you help a landlord with a rental near Kentish Town West station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or drop us an email and tell us about the property, and we will give you a clear quote.
Is parking a problem for a job in Chalk Farm?
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.
How long does the job take?
That depends on how much there is to do, but as a guide it takes anything from a few hours to several days, depending on the building. We will tell you when we quote.
Should I point up the gap in my brickwork?
No, not where the gap is a movement joint. Pointing it stops it working and can lead to cracking. We’ll reseal it with a flexible sealant.
What is a movement joint?
Walls move with heat, cold and moisture, and planned joints take up that movement. The gap is sealed with a flexible sealant over backing rod.
Do you cover Chalk Farm?
Yes. We work in Chalk Farm, as part of our work across South East England, London and Scotland. To book, ring 0345 464 0079 or drop us an email.
Will the new joint stand out?
We choose a sealant colour to suit the brick, stone or render. Exterior sealants come in a good range of colours.
Are you an approved applicator?
Yes. We’re approved under the ARBOMaster scheme, the approved applicator scheme for Arbo sealants.
How to look after the new joints
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Do not let climbing plants root in the sealant
- Point out the joints to other trades
- Look over the joints every year, ideally after winter
- Keep movement joints as flexible joints, not mortar
Give the sealant the cure time we tell you before anything rubs against it. The surface skins over quickly, but full cure takes longer.
Water getting behind cladding or render can go unnoticed for a long time. When it finally shows inside, the joint may have been open for years.
How the job changes by surface
Copings and trims
Joints in copings, parapets and trims are exposed to the worst of the weather. Each is resealed with a weatherproof, flexible sealant.
Brickwork movement joints
Clay brickwork grows slightly over its life and moves with the weather. The movement joint takes that up, so its sealant has to stay flexible.
When it is not the sealant
We’d rather tell you now than do work that won’t last, so here’s what sealant can’t put right:
- Structural movement, which needs a surveyor or engineer
- Cracked brickwork or render that needs a builder or plasterer
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
If in doubt, ring 0345 464 0079 or drop us an email and we will say what we think.
What we seal
- Joints between brick and frames
- Render & cladding joints
- Copings & trims
- Façade panels
- Brickwork movement joints
- Concrete & block
What we are called out for in Chalk Farm
Joints sealed without backing rod, or far too deep, rarely last. If the sealant sticks to the back as well as the sides, it can’t stretch and rips as the joint opens.
If you can see any of these, it’s time to have the joints looked at:
- Sealant that has lost its bond to the brick or render
- Movement joints with cracked, split or missing sealant
- Failed sealant between panels on a façade
- Damp patches traced to an open external joint
Chalk Farm is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
What to look for in a quote
- How long the guarantee is
- Whether they’re fully insured
- Is the old sealant removed completely?
- Who does the work, and how experienced they are