Greater London · England
External & façade joints in North End, Greater London
Movement joints in North End need attention? We cut out the old, prepare the joints and apply the right sealant, with a 12-month guarantee.
- Sealant pulling away from one side of the joint
- Leaking joints around cladding and façade panels
- Joints pointed up with cement by mistake
Different surfaces, different methods
Joints between dissimilar materials
Joints where frames, sills or panels meet the wall are common leak points. We cut out the old sealant and reseal with a product suited to both surfaces.
Brickwork movement joints
Vertical joints in long brick walls let the brickwork expand without cracking. We reseal them with a low-modulus sealant over backing rod in a colour to suit the brick.
External mastic in North End, done properly
Many failed façade joints only get noticed once there’s a stain or a damp patch inside. We look over the joints, agree the ones to renew and reseal with a flexible, weatherproof product in a colour to suit. If you’re dealing with rigid filler in a joint that should flex and gaps where render, brick and frames meet, we can put it right, on copings & trims, concrete & block and render & cladding joints alike.
Modern London flats rely on sealed movement joints and cladding joints. Period houses have different weak points, such as gutter joints, trims and the line where an extension meets the old wall, and both kinds of building are found across London.
We stand behind the work with a 12-month guarantee.
- Location
- North End (NW3, NW11, N2)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
When it is not the sealant
Some problems need a builder, plumber or other trade rather than us:
- Subsidence or other structural problems
- Cracked brickwork or render that needs a builder or plasterer
- Render that is blown, hollow or coming away
If you’re not sure, just call 0345 464 0079 or email us and we’ll give you a straight answer.
Joints and surfaces we work on
- Copings & trims
- Brickwork movement joints
- Render & cladding joints
- Concrete & block
- Façade panels
- Joints between brick and frames
Work for landlords, hotels and businesses
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance.
We work for letting agents and landlords as well as homeowners. Sealant work between tenants keeps a property looking cared for before the next move-in.
DIY versus a professional finish
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
What external mastic looks like in North End
In terraces and conversions, gutters and walls are often shared with the neighbours, so check who is responsible for the outside before booking. Historic houses like Heath House (about 0.3 miles south) are a reminder that the area around North End 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.
North End is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. For site and facilities teams at buildings such as The King Alfred School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s. In the older streets around Church of St Alban the Martyr, older walls, gutters and the joints where extensions meet them need a flexible sealant.
North End is about 1 mile north of Greenhill, in Greater London. Anywhere in NW3, we cover external mastic for homes and businesses. Our area takes in 764 places across Greater London, from the larger towns to small villages. For nearby work, see our London page.
Here we cover the NW3, NW11 and N2 postcode area for external mastic. Streets in the area include Sandy Road, Park Avenue and Platt's Lane. Being close to the A502, North End is easy for our applicators to reach for external mastic. Neighbouring places we cover for external mastic include Vale of Health (1 mile south-east), Childs Hill (1 mile south-west), Golders Green (1 mile north-west), Greenhill (1 mile south) and West Hampstead (1 mile south). Within a short drive, we also cover London (6 miles south-east), City of Westminster (4 miles south), Marylebone (4 miles south-east), Kensington (5 miles south), St Pancras (4 miles south-east) and Shoreditch (5 miles south-east).
Near you in North End
Around North End, our work takes us to homes and buildings near The Old Bull and Bush pub, Childs Hill Park and The Henrietta Barnett School. For rail, the closest station is Hampstead Heath station, about 1.1 miles south-east. Nearby you will also find O2 Centre (1.4 miles south) and New End Hospital (0.7 miles south). Open spaces near North End include Turner's Wood and Darland's Lake.
Leave it or put it right?
A failed movement joint lets water into the wall and can run behind render or cladding. Dealing with it early keeps the repair to the joint, rather than the wall around it. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler for homes in North End.
Rather than a set price list, we price the job in front of us: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
What you get with us
- Arbo and Everbuild products
- Anti-fungal silicone where joints get wet
- Any old sealant cut out fully, not covered over
- Tidy, careful work
Take a look at how sealant jobs are priced or what customers say.
How the visit works
We bring everything the job needs with us, so you do not need to buy or prepare anything. After a quick look at the joints together, the area is protected and the work begins. Most jobs take a few hours to a few days, depending on the length of joint and the access. In North End, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- We start by walking round the building and agreeing the joints and the access.
- Every bit of old sealant and any mortar or debris is cut out.
- The faces are brushed clean and primed where the product requires it.
- Backing rod sized to the joint goes in to set the depth.
- The exterior sealant is applied, tooled and checked along its length.
Before we arrive
- Let us know if you’ve seen damp or leaks
- For indoor joints, keep the area dry beforehand if you can
- For business premises, tell us about site rules or sign-in
Get a quote
It all starts with a short chat. Describe the problem, the location and the size of the job, and we’ll talk you through what we’d do. Whenever you’re ready, phone 0345 464 0079 or send us an email.
Related advice
Common questions in North End
I let a flat near Hampstead Heath station. Can you help?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or email us and tell us about the property, and we will give you a clear quote.
Do you cover North End for external mastic?
Yes. We work across London and the South East, and North End is part of that. Just phone 0345 464 0079 or send us an email with a few details of the job, and we’ll give you a clear price.
Can new sealant go over the old?
No, because it fails. We remove every bit of old sealant first, so the new sealant bonds properly.
Can you seal joints between render and window frames?
Yes. Different materials move at different rates, so a flexible sealant is needed where they meet. The sealant is matched to both sides.
What do you need from me for a quote?
Let us know what needs doing and where, plus pictures if you have them. If we need more, we will ask.
Is there a guarantee?
Yes, for a year. If anything is not right with the work within the year, let us know and we’ll sort it.
Do you remove the old sealant?
Yes, every time. New sealant will not bond properly to old, so the joint is cleaned back first.
How long does the job take?
Most jobs take a few hours to a few days, depending on the length of joint and the access, including preparation and clearing up. We will confirm how long when we quote.
Places near North End
What else we do in North End
How to look after the new joints
So the new joints stay in good condition:
- Keep soil, plants and ivy away from the joints
- Look over the joints every year, ideally after winter
- Keep movement joints as flexible joints, not mortar
- Avoid pressure-washing directly into sealant joints
Make sure anyone working on the wall later knows where the movement joints are. They should be kept open and resealed, not filled.
An open movement joint lets rain into the wall every time it pours. That can lead to damp patches, staining and frost damage.