Greater London · England
External & façade joints in Brockley Hill, Greater London
Sealing brickwork movement joints, render, cladding and façade joints for homes and businesses in Brockley Hill and across Greater London. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Rigid filler in a joint that should flex
- Damp patches traced to an open external joint
- Leaking joints around cladding and façade panels
About our external mastic in Brockley Hill
Where two different materials meet, such as brick and render or blockwork and metal, they move at different rates. A flexible sealant bridges the two where mortar or filler would crack. We work on joints between brick and frames, copings & trims and brickwork movement joints, and the jobs we see most are joints pointed up with cement by mistake and rain getting behind render or cladding at a joint.
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.
The work is covered for a year after we finish. If anything isn’t right with it, ring 0345 464 0079 or email us.
- Location
- Brockley Hill (HA7, HA8, WD6)
- Region
- Greater London
- Cover
- A year, on every job
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
What we do, step by step
At the end, we look at the finished work together. The visit itself usually takes a few hours for a handful of joints, longer for a whole elevation, depending on the size of the job. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Brockley Hill. A visitor permit or a nearby bay makes the visit run more smoothly.
- We look at every joint and agree a colour to suit the wall.
- We take out the old sealant until the faces are sound.
- Closed-cell backing rod is pushed in so the sealant bonds to two sides only.
- Primer is applied wherever the sealant needs it.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Getting ready for the visit
- Mention any leaks or damp you’ve noticed
- Clear items away from the joints we are working on
- Plan for the work area to be out of bounds to pets and children
Ask for a quote
There’s no standard price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To get started, phone 0345 464 0079 or send us an email.
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What we’re called out for in Brockley Hill
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.
These are the problems we are asked about most:
- Weeds or debris growing in open joints
- Hard, crazed mastic that has stopped moving
- Sealant that has lost its bond to the brick or render
- Rigid filler in a joint that should flex
If you look after a building such as London Academy, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
What to look for in a quote
- What insurance they hold
- How the colour is chosen
- How the joint is cleaned and prepared
- How long the guarantee is
Outside joints around Brockley Hill
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. Historic houses like Headstone Manor (about 3.4 miles south-west) are a reminder that the area around Brockley Hill has older buildings as well as new. In older buildings, older walls and rooflines need a sealant that moves with them and suits the material.
Homes close to St Peter include some older properties, and older walls, gutters and the joints where extensions meet them need a flexible sealant. As a London address, Brockley Hill can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Brockley Hill is about 1 mile north of Stanmore, in Greater London. From the centre of Brockley Hill to the outskirts, we cover external mastic for every kind of property, from flats and houses to offices and hotels. Brockley Hill is one of 764 places in Greater London where we work for external mastic. Our London page covers work nearby, about 13 miles away.
Here we cover the HA7, HA8 and WD6 postcode area for external mastic. If you need external mastic at a property on Wood Lane, Brockley Avenue and Pipers Green Lane or a nearby road, we can help. Nearby, we also carry out external mastic in Stanmore (1 mile south), Bushey Heath (2 miles west), Belmont (2 miles south-west), Harrow Weald (2 miles south-west) and Bushey (3 miles north-west). We also work in nearby towns such as London (13 miles south-east), City of Westminster (10 miles south-east), Marylebone (10 miles south-east), Kensington (10 miles south-east), St Pancras (11 miles south-east) and Shoreditch (12 miles south-east).
Local landmarks in Brockley Hill
Typical jobs here are in homes near Abercorn Arms Public House, Aylward Primary School and Edgwarebury Park and the streets around them. The closest station to Brockley Hill is Elstree & Borehamwood station, about 1.8 miles north-east of the centre. Well-known places in the area include Royal National Orthopaedic Hospital (under half a mile north-west) and Hilfield Castle (2.2 miles north-west). Green spaces nearby include Darland's Lake and Edgware Way Grassland.
DIY versus a professional finish
A careful DIYer can reseal a simple joint, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. All the old material has to come out first.
What affects the quote in Brockley Hill
Some jobs are bigger than they look, and some smaller. The main factors:
- How easy the joints are to reach
- The size of the job
- Whether there’s mould to deal with
- Working hours on commercial sites
We do not show prices on the website, because the cost depends so much on the job itself. Call for a quick quote and we’ll talk you through it.
Asking for a quote
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- How many joints, rooms or windows are involved
- The address or postcode of the job
- A few photos by email, if you can
- What’s wrong with the joints now
Every job is quoted individually, so the first step is telling us about yours. Simply ring 0345 464 0079 or drop us an email and describe the job.
Nearby places to Brockley Hill
What else we do in Brockley Hill
For landlords and businesses
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.
If you manage several properties in or around Brockley Hill, jobs at different addresses can be quoted together. Send us the addresses and the work at each, and photos by email help.
What we can’t put right
New sealant can’t fix everything, and we will tell you before any work starts. Sealant will not put right:
- Movement that’s more than a sealant joint can take
- Damp from another source, such as a leaking gutter or a bridged damp-proof course
- Adding movement joints to masonry that has none
Not sure which it is? You can call 0345 464 0079 or email us and we will tell you honestly before booking.
Where we work in Brockley Hill
- Concrete & block
- Render & cladding joints
- Façade panels
- Copings & trims
- Brickwork movement joints
- Joints between brick and frames
Keeping the joints in good condition
After the cure time, these simple habits help:
- Act on the first splits you see
- Make sure movement joints aren’t pointed over
- Ask before painting over external sealant
- Show decorators and builders where the movement joints are
Don’t let soil, plants or ivy build up against the new joints. Damp material against the sealant shortens its life.
Leaks behind façade panels and render often go unseen. By the time there’s a damp patch, the damage can be well established, so it’s worth resealing at the first signs.
Common questions in Brockley Hill
Is Brockley Hill in your area for external mastic?
Yes, Brockley Hill is within the area we cover. Our work covers London and the South East. You can call 0345 464 0079 or send us an email and let us know what needs doing, and we’ll give you a clear price.
I let a flat near Elstree & Borehamwood station. Can you help?
Yes, we work for letting agents and landlords. You can phone 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before any work starts.
Does someone need to be in?
It depends on the job. For work indoors, someone needs to let us in, while outside work can sometimes be arranged differently.
How long does external mastic last?
It depends on the exposure, the movement and the product. Treat it as a maintenance item and look at it yearly and renew it when it starts to fail.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status, and we’re fully insured.
Do you remove the old sealant?
Yes. Sealing over old sealant is the main reason resealing fails early, and it’s something we never do.
Can you seal joints between two different materials?
Yes. Different materials move at different rates, so the joint between them must be flexible. We choose one that suits both surfaces.
How long before the joint can be used?
Cure times vary by product. We tell you how long to leave it before we go.