Greater London · England
Mapesbury External Mastic
Movement joints in Mapesbury need attention? We remove the old material, prepare the joints and seal them properly.
- Sealant that has lost its bond to the brick or render
- Moss and dirt in joints with no sealant left
- Brick movement joints where the sealant has split
How we handle external mastic in Mapesbury
As ARBOMaster approved applicators, we choose exterior sealants to suit the joint and the surfaces. Some surfaces need a primer before sealing and we use one wherever it does. We work on façade panels, render & cladding joints and joints between brick and frames, and common reasons people get in touch are weeds or debris growing in open joints and rigid filler in a joint that should flex.
In London terraces and converted houses, gutters and walls are often shared with the house next door, so a leaking gutter joint or failed wall joint can affect more than one home. In a converted house in Mapesbury, it’s worth checking who is responsible for the outside before booking.
We guarantee the work for a year. If something is not right with it in that time, tell us and we will put it right.
- Where
- Mapesbury (HA9, HA0, NW10)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
What the job involves on each surface
Concrete and blockwork
Concrete faces can be dusty and porous, so cleaning and priming matter. A primer goes on where the product requires one.
Joints between dissimilar materials
Brick against render, concrete against metal, stone against timber: every change of material is a joint. We seal the joint with a flexible exterior sealant so neither cracks the other.
What external mastic looks like in Mapesbury
London terraces and converted houses often share gutters, downpipes and walls, so it’s worth agreeing who is responsible before work starts. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Letting a property close to Wembley Stadium station? Then failed wall and movement joints let damp in, so they’re worth checking between tenancies. Homes close to St Michael the Archangel include some older properties, and an extension built onto an older house moves differently, and the joint between them takes the strain.
Mapesbury is about 1 mile south-east of Wembley, in Greater London. Homes, rented property, offices and hotels in Mapesbury can book us for external mastic. The work is guaranteed for a year. Our area takes in 764 places across Greater London, from the larger towns to small villages. London is on our list too, about 9 miles from Mapesbury.
We cover every part of the HA9, HA0 and NW10 postcode area for external mastic and the streets around it. If you need external mastic at a property on London Road, Harrow Road and Cecil Avenue or a nearby road, our applicators can take on the job. Neighbouring places we cover for external mastic include Tokyngton (1 mile south-east), Stonebridge Park (1 mile south-east), Wembley Park (1 mile north), Wembley (1 mile north-west) and Brent Park (1 mile east). Within a short drive, we also cover London (9 miles south-east), City of Westminster (6 miles south-east), Marylebone (6 miles east), Kensington (5 miles south-east), St Pancras (7 miles east) and Shoreditch (9 miles east).
Around Mapesbury
Locally, jobs take us to homes and businesses close to The Swaminarayan School, Hilton London Wembley pub and St. Raphael's Edible Garden. There’s a railway station in Mapesbury itself: Wembley Stadium station. Well-known places in the area include Brent Museum and Archives (2.2 miles east) and Neasden Hospital (0.9 miles east). Not far away are Fox Wood and Middle Lake.
Questions from Mapesbury
Do you cover Mapesbury for external mastic?
Yes. We work across London and the South East, and Mapesbury is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job, and we’ll give you a clear price.
Do you work for landlords with property near Wembley Stadium station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Where are you based?
Our base is in Crawley, West Sussex, and we work across South East England, London and Scotland.
Why is there a gap in my brick wall?
It’s a deliberate gap that lets the wall expand and contract without cracking. It’s sealed with a flexible sealant, not mortar.
Do I need to be at home?
For indoor joints, yes, someone needs to let us in. Once we have agreed the job, you do not need to watch us work.
Can you match the colour of my brickwork?
There’s a good range of exterior colours, including greys, browns, whites and stone tones. We pick the one that suits your wall best so it does not stand out.
When is the sealant fully cured?
Most sealants are touch-dry well before they’re fully cured. We’ll tell you how long to leave the joint before we leave.
Is there a guarantee?
Yes. All our work carries a one-year guarantee.
Do you need external mastic in Mapesbury?
Using the wrong sealant is another common reason. A high-modulus or general-purpose sealant can be too rigid for a busy joint, so it pulls away from the edges.
Keep an eye out for these signs:
- Plants rooting in failed movement joints
- Weathered mastic that no longer stretches
- Leaking joints around cladding and façade panels
- Joints pointed up with cement by mistake
For site and facilities teams at buildings such as St Joseph's RC Infant School, movement joints, cladding joints and gutters on larger buildings need the same care as a house’s.
Comparing quotes
- What happens if they find a problem under the old sealant
- Whether all the old sealant comes out first
- How the joint is cleaned and prepared
- Whether VAT is included
Quotes for external mastic in Mapesbury
Some jobs are bigger than they look, and some smaller. What affects the quote:
- Any working-time requirements on site
- The old material and how stubborn it is
- How easy the joints are to reach
- Any mould that needs treating
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please phone 0345 464 0079 or email us.
What to tell us for a quote
What to tell us when you ask for a quote:
- Where the property is
- What the problem is, such as mould, gaps, leaks or cracking
- If it’s domestic, commercial or a hotel
- Pictures of the joints, sent by email
We do not publish a price list. Instead, we give you a clear price for your job. To get started, ring 0345 464 0079 or email us.
What we can’t put right
We will not take on work that won’t last, so these are the limits:
- Cutting new joints into brickwork, which is building work rather than sealant work
- Damp that is not coming from the joint
- Structural movement, which needs a surveyor or engineer
Not sure which it is? You can phone 0345 464 0079 or drop us an email and we will tell you honestly before booking.
Where we work in Mapesbury
- Copings & trims
- Brickwork movement joints
- Render & cladding joints
- Façade panels
- Concrete & block
- Joints between brick and frames
How it works
All our tools and materials come with us in the van. Once we have agreed what’s being done, we protect the area and start. Most jobs take anything from a few hours to several days, depending on the building. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Mapesbury. A visitor permit or a nearby bay makes the visit run more smoothly.
- First, the joints are inspected and the access agreed.
- Every bit of old sealant and any mortar or debris is cut out.
- Joint faces are cleaned back and primed if the sealant needs it.
- Backing rod sized to the joint goes in to set the depth.
- We apply the sealant, tool it and check the whole run.
Preparing for the visit
- Let us know about stairs, lifts or work at height
- Where the joints are inside, avoid wetting them before we arrive
- Tell us about any water getting in
Ask for a quote
If you are in Mapesbury and need external mastic, ring 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and we’ll agree the price before any work begins.
Advice
Places near Mapesbury
Other services in Mapesbury
Looking after it afterwards
Joint life depends on how it’s used and looked after. We suggest:
- Never let anyone fill a movement joint with mortar
- Get split or bare joints resealed while the damage is small
- Check external joints each spring
- Keep high-pressure jets off the joints
Keep the joints clear of soil, plants and climbing growth. Damp material against the sealant shortens its life.
Small splits are the time to act. Then it’s a straightforward cut-out and reseal.
Leave it or put it right?
A low-modulus sealant is chosen because it moves without pulling hard at the edges. That matters on brick, render and concrete, which can be weaker at the face. Too stiff a sealant can pull at the edges and break them. Damp from a failed joint spreads quietly in older London brickwork and timber, and by the time it shows on a wall or ceiling in Mapesbury, the repair is bigger than the sealant job would have been.
No two jobs are quite the same, so each one gets its own quote. Size, access and the product the joint needs all play a part, and we will explain the quote if you ask.
Why choose Mr Mastic in Mapesbury
- Homes, businesses and hotels
- A 12-month guarantee on all work
- A choice of colours where the product allows
- 180+ five-star Google reviews
Take a look at our cost guide and our reviews.