Greater London · England
External & façade joints in Muswell Hill, Greater London
External mastic for Muswell Hill, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Plants rooting in failed movement joints
- Failed seals between different materials
- Hard, crazed mastic that has stopped moving
About our external mastic in Muswell Hill
A movement joint is a deliberate break that lets a wall expand and contract. Its sealant has to flex with the building, season after season, so once it splits or hardens, the joint stops working and water gets in. If you are dealing with joints pointed up with cement by mistake and leaking joints around cladding and façade panels, we can put it right.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in Muswell Hill, tell us how high the joints are and how to reach the back of the building.
There’s a 12-month guarantee on every job, large or small.
- Place
- Muswell Hill (N10, N2, N8)
- Region
- Greater London
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Aftercare tips
No joint lasts for ever, but care makes a real difference. Our tips:
- Never let anyone fill a movement joint with mortar
- Do not let climbing plants root in the sealant
- Leave the joints unpainted unless we’ve said otherwise
- Look over the joints every year, ideally after winter
Only paint over the joint if we have confirmed the sealant can take paint. Paint can crack on a flexible joint and spoil the finish.
Small splits are the time to act. At that stage it’s a simple cut out and reseal with no damage behind it to deal with.
Surface by surface
Joints between dissimilar materials
Wherever two materials meet, they move differently. We seal the joint with a flexible exterior sealant.
Cladding and façade panels
Cladding and façade panels are normally separated by sealed joints. We reseal them with a sealant suited to the panel material.
How the visit works
There’s no need to move everything out before we come, only the area right around the joints. We protect the rest, and the job takes anything from a few hours to several days, depending on the building in most cases. In Muswell Hill, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- Each joint is checked and the colour of the new sealant agreed.
- We take out the old sealant until the faces are sound.
- Backing rod goes in so the sealant can stretch between the two faces.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- Tell us about access, such as stairs, a lift or high-level joints
- Let us know about parking restrictions
Ask for a quote
For external mastic in Muswell Hill, phone 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you’ll get a clear quote before work begins.
Read more
Leave it or put it right?
A properly done movement joint is an even line in a colour that suits the wall. A hurried job with smeared edges and no backing looks worse and fails sooner so it’s worth doing right. In London conversions, one flat’s bathroom is often above another flat’s ceiling, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble.
No two jobs are quite the same, so each one gets its own quote. The number of joints, how easy they are to reach and the sealant needed all play a part, and we’ll explain the quote if you ask.
Why book with us
- We leave the area clean and tidy
- Colour picked to suit the job
- Old sealant always removed completely
- Quality sealants from Arbo and Everbuild
Take a look at our cost guide or customer reviews.
Muswell Hill questions
Can parking be tricky for a visit in Muswell Hill?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
I let a flat near Alexandra Palace station. Can you help?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or drop us an email and tell us about the property, and we will give you a clear quote.
Are you ARBOMaster approved?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
What should I tell you?
Just the basics: the address or postcode, what’s wrong and any access issues. After that, simply ring 0345 464 0079 or drop us an email.
Does someone need to be in?
We need access to the joints, so we’ll agree that with you when we book. For inside work, that normally means someone being in.
What does external mastic cost?
The cost depends on the size of the job, access and how much old sealant has to come out. Call for a quick quote and we will talk you through it.
How often do external joints need resealing?
It varies with how exposed the wall is and how much the joint moves. Look for splits, hardening or edges coming away and have them redone then.
Why do you put foam in the joint first?
Backing rod controls the sealant depth and keeps it off the back of the joint. Then the sealant bonds to two faces and can move.
Landlord and commercial work in Muswell Hill
For anyone letting property in or around Muswell Hill, several properties can go on one quote. Send us the addresses and the work at each.
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
DIY sealant or a professional job?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Muswell Hill buildings and the weather
Historic houses like Athlone House (about 1.6 miles south-west) are a reminder that the area around Muswell Hill 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. London terraces and converted houses often share gutters, downpipes and walls, so it’s worth agreeing who is responsible before work starts.
If you look after a building such as Muswell Hill Primary School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. For landlords with property near Alexandra Palace station, outside joints that have cracked can let damp into a rental, so check them between lets. Muswell Hill is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Muswell Hill is about 2 miles east of Finchley, in Greater London. We carry out external mastic for homeowners, landlords and businesses in Muswell Hill. We cover 764 towns and villages across Greater London, from the larger towns to small villages. Our London page covers work nearby.
Work in N10, N2 and N8 works the same way as everywhere else we cover. If you need external mastic at a property on Cecil Road, The Avenue and Elgin Road or a nearby road, we can help. With the A504 close by, Muswell Hill is easy for our applicators to reach for external mastic. Neighbouring places we cover for external mastic include Fortis Green (1 mile west), Hornsey (1 mile east), Crouch End (1 mile south-east), East Finchley (1 mile west) and Highgate (1 mile south). Within a short drive, we also cover London (7 miles south), City of Westminster (5 miles south), Marylebone (5 miles south), Kensington (7 miles south), St Pancras (5 miles south) and Shoreditch (5 miles south-east).
What’s near Muswell Hill
Around Muswell Hill, our work takes us to homes and buildings near Tollington School, Alexandra Park and Fortismere School. The nearest railway station is Alexandra Palace station, roughly 1.1 miles north-east. A little further out are The Mall Wood Green (1.5 miles east) and Kenwood House (1.8 miles south-west). The countryside around Muswell Hill includes Glebelands Local Nature Reserve and Darland's Lake.
What affects the cost of external mastic
Your quote is based on your job. We take into account:
- Whether old sealant or filler has to be cut out
- Mould in or behind the old joints
- The size of the job
- How many areas need sealing
The cost reflects the work involved, not a rough estimate. That’s why we ask about the job first.
What to tell us for a quote
There’s no need for technical detail. It helps if you can tell us:
- The rough size of the job
- Any previous sealing or DIY work
- If it’s domestic, commercial or a hotel
- Photos by email, if that’s easy
It all starts with a short chat. Describe the problem, the location and the size of the job. When it suits you, call 0345 464 0079 or send us an email.