Greater London · England
Sand Mastic in West Hampstead
Sand mastic for West Hampstead, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- A silicone bead on a sash window that spoils the look
- Old sand mastic that has cracked, crumbled or fallen out
- Draughty sash windows at the surround
How the job changes by surface
Tenement and terrace windows
Upper-floor windows need access planning. Tell us the height and we will confirm what’s needed.
Sash and case windows
Sash windows are where we do most sand mastic work. We renew the mastic round each box.
About our sand mastic in West Hampstead
For a listed home or one in a conservation area, ask your local planning authority if consent is needed before window work. Like-for-like sand mastic is often the preferred finish. Typical jobs include patchy fillers round a sash window and window mastic to renew ahead of painting, on period & listed homes, stone surrounds and sash and case windows.
Many London homes are flats, with windows high above the street. In a converted house or block, the lease normally says who is responsible for the windows, so it’s worth checking before booking.
Your job is guaranteed for a year, as with all our work.
- Where
- West Hampstead (NW3, NW6, NW2)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
What happens if it’s left?
Not every filler suits an old window surround. Sand mastic matches what was there and that can be important for listed homes. In a flat in West Hampstead, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Leaving a failed joint generally makes the job bigger, not smaller, because water and mould keep working on it. If you are unsure, call 0345 464 0079 or drop us an email and we will give you an honest view and a quote.
Why book with us
- Neat joints and a tidy finish
- Rated 4.9 stars on Google
- Anti-fungal sanitary silicone in wet areas
- Full insurance on every job
See our cost guide or what customers say.
Common problems we fix in West Hampstead
Paint, silicone or cement used over old mastic causes problems. They do not move with the timber and we normally remove them.
It’s worth asking for a quote if you see:
- Mastic worn away on windows facing the weather
- Patchy fillers round a sash window
- Gaps between timber frames and stone or brick
- Mastic round period door frames that has failed
West Hampstead is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
What your quote should include
- When the joint can take water or movement
- How the surfaces are prepared before sealing
- Whether you can choose the colour
- Whether all the old sealant comes out first
Your questions about sand mastic in West Hampstead
Do you cover West Hampstead for sand mastic?
Yes. We work across London and the South East, and West Hampstead is part of that. Just call 0345 464 0079 or email us with a few details of the job.
Do you work for landlords with property near Finchley Road & Frognal station?
Yes. We work for landlords and agents as well as householders, and several properties can go on one quote. You can phone 0345 464 0079 or drop us an email with the details for a clear quote.
What sealant do you use?
The product depends on the job: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. We use products from Arbo and Everbuild.
Can I choose the sealant colour?
We help you choose a colour that suits. The choice depends on the product the joint needs.
What should I tell you?
Where the job is, what the problem is and roughly how big it is. If you can, email a few pictures.
Should I try DIY first?
It depends on the job. High-level, external movement and fire-rated joints are professional jobs, while a short indoor joint may be within reach.
Do I need to be at home?
It depends on the job. Inside work needs someone to give us access, and for outside work we’ll agree access with you when we book.
Is it OK to seal over old sealant?
No, and we never do. It may look fine at first, but the new bead soon lifts. Removing the old sealant completely is the only lasting way.
West Hampstead homes and the weather
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Fenton House (about 0.5 miles north-east) are a reminder that the area around West Hampstead has older buildings as well as new. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
In the older streets around Presbyterian Church Of St Andrew, frames set in older brick or stone need a sealant that suits the wall as well as the frame. If you let a flat or house near Finchley Road & Frognal station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
West Hampstead is about 3 miles north-west of City of Westminster, in Greater London. Anywhere in NW3, our applicators can take on sand mastic. West Hampstead is one of 764 towns and villages in Greater London where we work. There’s also a page for London, roughly 6 miles from West Hampstead.
Every address in NW3, NW6 and NW2 is covered for sand mastic, from the main roads to the quietest streets. Local streets include Mill Lane, Acol Road and Ajax Road. West Hampstead is on the A502, so it’s easy for us to get to with everything needed for sand mastic. Close by, we work in Fortune Green (1 mile west), Hampstead (1 mile east), Greenhill (1 mile east), Childs Hill (1 mile north-west) and Vale of Health (1 mile north-east). Larger places within reach include London (6 miles south-east), City of Westminster (3 miles south-east), Marylebone (3 miles south-east), Kensington (4 miles south), St Pancras (4 miles south-east) and Shoreditch (5 miles east).
Near you in West Hampstead
Around West Hampstead, our work takes us to homes and buildings near South Hampstead High School, Holly Bush pub and Kilburn Grange Park. West Hampstead has its own railway station: Finchley Road & Frognal station. A little further out are Isokon Gallery (1.2 miles east) and New End Hospital (0.5 miles north-east). Green spaces nearby include Parliament Hill and Westbere Copse.
Keeping the joints in good condition
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Avoid heavy scraping on the mastic joint
- Renew mastic before redecorating the windows
- Ask a joiner to look at soft timber first
- Clear gutters so water doesn’t pour onto the windows
Avoid sealing over the mastic with silicone. If you see a crack, ask us to take a look rather than patching it.
Renewing mastic before redecorating saves doing it twice. Painting over failed mastic hides the problem for a while.
When it isn’t the sealant
Some problems need a builder, plumber or other trade rather than us:
- Sashes that need overhauling
- Timber that has rotted
- Planning or listed building consent (your local planning authority decides)
Not sure which it is? You can call 0345 464 0079 or drop us an email and we will tell you honestly before you book.
What we seal
- Tenement windows
- Stone surrounds
- Sash and case windows
- Timber door frames
- Period & listed homes
- Brick reveals
What affects the cost of sand mastic
We quote each job individually. These are the things that affect it:
- When we can work, for business premises
- Any mould that needs treating
- How many rooms, windows or areas are involved
- Whether old sealant or filler has to be cut out
What it costs depends on the size of the job, how much old material has to come out and how easy the joints are to reach. We give a clear quote before work begins.
What we need to know
The more you tell us, the more accurate the quote. When you get in contact, it helps to mention:
- If someone has resealed it before
- The type of property
- How we’d reach the joints
- The problem you’ve noticed
To get a quote, call 0345 464 0079 or email us and tell us where the job is and what the problem looks like. We will give you a clear price before any work starts.
What we do, step by step
There’s no need to move everything out before we come, only the area right around the joints. Everything nearby is protected, and the work takes a few hours per window, depending on the condition of the joints in most cases. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in West Hampstead. A visitor permit or a nearby bay makes the visit run more smoothly.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- We pack any deep gaps so the mastic sits at the right depth.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
Preparing for the visit
- Let us know about earlier repairs to the joints
- For business premises, tell us about site rules or sign-in
- Tell us if parking is tricky
How to get a quote
For sand mastic in West Hampstead, ring 0345 464 0079 or drop us an email. Tell us what the problem is and where, and you’ll get a clear quote before we start.