Greater London · England
External Mastic in Hampstead Garden Suburb
External mastic in Hampstead Garden Suburb from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Sealant pulling away from one side of the joint
- Cracked joints where brick meets render or frames
- Water getting into walls through failed joints
Can I do it myself?
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
A careful DIYer can reseal a simple joint, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
How we handle external mastic in Hampstead Garden Suburb
Short cuts in external joints show up within a season or two. New sealant over old, joints packed with mortar and beads with no backing rarely last long. We take the old material out and do it properly. If you have gaps where render, brick and frames meet and leaking joints around cladding and façade panels, we can help, on copings & trims, brickwork movement joints and concrete & block alike.
Working on the outside of a London home means planning access: shared paths, upper floors and parking. For a home in Hampstead Garden Suburb, tell us how high the joints are and how to reach the back of the building.
You’re covered for a year from the day we finish. If there’s a problem with it, please ring 0345 464 0079 or drop us an email.
- Location
- Hampstead Garden Suburb (NW11, N2, N3)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Price
- A clear price before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Also near Hampstead Garden Suburb
Other services in Hampstead Garden Suburb
Honest limits
In fairness, some problems need a different trade:
- Subsidence or other structural problems
- Cracked brickwork or render that needs a builder or plasterer
- Render that’s blown, hollow or coming away
If you are not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer.
Where we work in Hampstead Garden Suburb
- Façade panels
- Copings & trims
- Brickwork movement joints
- Joints between brick and frames
- Render & cladding joints
- Concrete & block
When to call us in Hampstead Garden Suburb
If plants are growing out of a joint, the sealant has normally failed or was never there. Roots and dirt hold water against the wall and speed up the damage.
Common reasons people contact us are:
- Movement joints filled with mortar instead of sealant
- Old sealant gone brittle and cracked
- Moss and dirt in joints with no sealant left
- Joints where the bead has come unstuck
Heath Hall, about 0.8 miles south-east, is one of the historic houses in the wider area around Hampstead Garden Suburb, and older homes nearby need a sealant that suits their walls.
What your quote should include
- What product goes in the joint
- What the quote includes, VAT included or not
- How hidden problems are handled
- Is the old sealant removed completely?
What the job involves on each surface
Cladding and façade panels
If the façade has a specified sealant, that’s what we use, or one the system allows. Tell us what the building has when you get in touch.
Joints between dissimilar materials
Each side of the joint may need its own preparation. We prepare both faces so the sealant bonds properly.
Hampstead Garden Suburb questions
Is Hampstead Garden Suburb in your area for external mastic?
Yes, Hampstead Garden Suburb is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or send us an email with a few details of the job.
I let a flat near Brent Cross West station. Can you help?
Yes. We work for landlords and agents as well as householders. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
What sealant do you use?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We explain the product when we quote.
How long does external mastic take?
Most jobs take a few hours to a few days, depending on the length of joint and the access, including the preparation. We’ll confirm how long when we quote.
Will you leave a mess?
Tidy work is part of the job. We protect what’s around the joints, and we clear up when we’re done.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that usually means someone at home.
How long does external mastic last?
That depends on the wall, the weather and the movement. Look for splits, hardening or edges coming away and have them redone then.
Where do you work from?
We work from Crawley. Our applicators cover Hampstead Garden Suburb, along with the rest of our area.
Keeping the joints in good condition
To keep the joints looking good and working properly:
- Wash walls gently around the sealant
- Tell anyone working on the walls about the movement joints
- Don’t let climbing plants root in the sealant
- Make sure movement joints are not pointed over
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, so it’s worth resealing at the first signs.
Why act early in Hampstead Garden Suburb
Pointing a movement joint with mortar might seem a neat fix, but it locks the joint solid. The wall then cracks somewhere else. A flexible sealant over backing rod is what the joint needs. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler.
Combining jobs into one visit is generally more efficient than separate visits, so tell us about everything that needs sealing. You’ll get one clear quote for the whole job.
What you get with us
- Quality sealants from Arbo and Everbuild
- Sanitary silicone with an anti-fungal additive in wet areas
- We are fully insured
- We leave the area clean and tidy
Take a look at what affects the cost or our reviews.
What happens on the day
We keep the work tidy and contained to the joints we’re treating. The job usually takes a few hours to a few days, depending on the length of joint and the access. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- Each joint is checked and the colour of the new sealant agreed.
- Failed sealant is removed back to clean, sound faces.
- Backing rod goes in so the sealant can stretch between the two faces.
- We prime the faces where required.
- A low-modulus exterior sealant is gunned in and tooled to a neat finish.
Before we arrive
- Keep pets and children clear of the area while we work
- For business premises, tell us about site rules or sign-in
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
If you are in Hampstead Garden Suburb and need external mastic, phone 0345 464 0079 or send us an email. A short description of the job and where it is helps us quote, and you will get a clear quote before work begins.
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What external mastic looks like in Hampstead Garden Suburb
London terraces and converted houses often share gutters, downpipes and walls, so check who is responsible for the outside before booking. The South East is one of the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
For landlords with property near Brent Cross West station, split movement joints are easy to miss on a rental until damp shows inside. Hampstead Garden Suburb is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Hampstead Garden Suburb is about 1 mile south-west of East Finchley, in Greater London. Jobs in Hampstead Garden Suburb get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. 764 places in Greater London are on our list. You can also see our page for London, roughly 7 miles from Hampstead Garden Suburb.
We work across NW11, N2 and N3 for external mastic. External mastic is available to properties on Maya Road, Oakwood Road and Bigwood Road and the roads around them. Hampstead Garden Suburb sits on or near the A1, which makes travel easy. Nearby, we also carry out external mastic in Temple Fortune (1 mile west), East Finchley (1 mile north-east), Golders Green (1 mile south-west), North End (1 mile south) and Vale of Health (1 mile south). Within a short drive, we also cover London (7 miles south-east), City of Westminster (5 miles south), Marylebone (5 miles south), Kensington (6 miles south), St Pancras (5 miles south-east) and Shoreditch (6 miles south-east).
What’s near Hampstead Garden Suburb
Locally, jobs take us to homes and businesses close to The Old White Lion pub, Brookland Infant and Nursery School and Lyttelton Playing Fields, among other places. Hampstead Garden Suburb’s nearest station is Brent Cross West station, about 2.1 miles south-west. Nearby you will also find Brent Cross Shopping Centre (1.7 miles west) and Jewish Museum - Finchley (0.9 miles north). Open spaces near Hampstead Garden Suburb include Darland's Lake and Parliament Hill.