Greater London · England
Sand Mastic in South Hampstead
Our applicators work in South Hampstead on traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old material cut out, joints cleaned and sealed neatly.
- A silicone bead on a sash window that spoils the look
- Draughts and rain around sash boxes
- Gaps where the frame meets the masonry
Surface by surface
Brick reveals
We rake out the old mastic and pack deep voids before the new mastic goes in.
Tenement and terrace windows
Upper-floor windows need access planning. Let us know the floor and we will confirm access.
Sand mastic in South Hampstead, done properly
Sand mastic has long been used to fill the joint between timber frames and masonry. It’s made from sand and a linseed-oil-based binder and built up by hand. On period homes, it looks right where silicone wouldn’t. If you have a silicone bead on a sash window that spoils the look and patchy fillers round a sash window, we can help.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
Your job is guaranteed for a year, as with all our work.
- Place
- South Hampstead (NW3, NW8, NW6)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Quotes for sand mastic in South Hampstead
You’ll get a clear quote before any work starts. It takes into account:
- When we can work, for business premises
- The number of rooms or windows
- Access and height
- Mould in or behind the old joints
We do not show prices on the website, because each job is priced on what it involves. For a quick quote, please phone 0345 464 0079 or drop us an email.
What we need to know
When you call or email, it’s useful to know:
- Where the job is, and your postcode
- Pictures of the joints, sent by email
- Whether it’s a home or a business
- Whether it has been sealed before
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is. When it suits you, call 0345 464 0079 or send us an email.
Sand mastic in South Hampstead: local notes
London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.
As a London address, South Hampstead can be tricky for parking: let us know about parking bays, permits or a driveway. Managing a site like The UCL Academy? Then the mastic around its windows and doors needs looking after like any other building’s.
South Hampstead is about 1 mile south of Hampstead, in Greater London. South Hampstead gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. South Hampstead is one of 764 towns and villages in Greater London where we work for sand mastic.
Postcode districts we cover here for sand mastic: NW3, NW8 and NW6. Streets in the area include Avenue Road, Acacia Road and Harben Road, and we cover them all. Close by, we work in Swiss Cottage (1 mile north), St John's Wood (1 mile south), Haverstock (1 mile east), Belsize Park (1 mile east) and Primrose Hill (1 mile east). Larger places within reach include London (4 miles south-east), Kensington (3 miles south-west), St Pancras (3 miles south-east), Shoreditch (4 miles east), Walthamstow (7 miles north-east) and Hoxton (4 miles east).
Landmarks near South Hampstead
Locally, jobs take us to homes and businesses close to Cafe Med pub, St. Mary's Town and Country School and Holy Trinity CofE Primary School. Other local landmarks include Cecil Sharp House (1.1 miles east) and Primrose Hill (0.6 miles east). There’s a railway station in South Hampstead itself: South Hampstead station. Well-known places in the area include Isokon Gallery (0.8 miles north-east) and O2 Centre (0.5 miles north-west). Open spaces near South Hampstead include Adelaide Nature Reserve and The Long Water.
When to call us in South Hampstead
Decorating can disturb tired mastic. It’s often found when windows are being prepared for paint.
Most people get in touch when they notice something like this:
- A silicone bead on a sash window that spoils the look
- Tired mastic found when preparing windows for paint
- Gaps round a timber door in stone or brick
- Crumbling sand mastic round a window
If you let a flat or house near South Hampstead station, any sash windows need sound mastic to keep draughts and rain out.
Comparing quotes
- The length of the guarantee
- When the joint can take water or movement
- How much experience the applicator has
- Whether you can choose the colour
What sealant work cannot fix
Sealant isn’t the answer to every problem, and we’d rather say so up front. Sealant won’t put right:
- Decayed frames that need repair
- Decisions on consent for listed homes
- Damaged stone surrounds
If in doubt, phone 0345 464 0079 or email us and we’ll say what we think before you book.
Where we work in South Hampstead
- Brick reveals
- Period & listed homes
- Stone surrounds
- Tenement windows
- Timber door frames
- Sash and case windows
FAQs for South Hampstead
Is South Hampstead in your area for sand mastic?
Yes, South Hampstead is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or email us and tell us what needs doing.
Is parking an issue for sand mastic in South Hampstead?
Parking in South Hampstead, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Is it messy?
Very little: the area around the joints is protected first, and we tidy up before we go.
I rent my home. Can I book you?
Yes, though it’s best to check with your landlord first. Landlords are often happy for the work to be arranged.
Can I paint the new mastic?
The usual advice is to leave sand mastic unpainted. If you are redecorating the window, ask us first and we will talk you through it.
Is sand mastic better than silicone for my windows?
It depends on the window. Period windows in stone or brick normally suit sand mastic and newer frames generally get a flexible sealant.
Is it OK to seal over old sealant?
No, because it fails. The old sealant always comes out first.
Do I have to be there?
That depends on where the joints are. For work indoors, someone needs to let us in, and for outside work we will agree access with you when we book.
What happens on the day
Every visit runs the same way: we look at the joints together, protect the area around them, carry out the job and tidy away. Most jobs take a few hours per window, depending on the condition of the joints. In a London area like South Hampstead, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we’re working on and whether there’s a lift.
- We check the window surrounds and agree which joints need renewing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic is not too thick.
- The mastic is mixed, pressed into the joint by hand and shaped.
- We dress the surface so it sits neatly against the masonry.
Preparing for the visit
- Where the joints are inside, avoid wetting them before we arrive
- Mention if the joints have been sealed before
- Mention any leaks or damp you’ve noticed
Getting a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Related advice
Can I do it myself?
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly.
Some sealant jobs are within reach of a careful DIYer, 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.
Why deal with it now?
If you are redecorating, renew the mastic first. Paint over cracked mastic will not stop the gaps and traditional guidance is to leave the new mastic unpainted. 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 South Hampstead, the repair is bigger than the sealant job would have been.
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, along with when we can work on site. Ask us for a quote and we’ll explain what it covers.
Why us?
- Homes, businesses and hotels
- We leave the area clean and tidy
- Anti-fungal silicone where joints get wet
- Approved under the ARBOMaster scheme
Read our cost guide or our reviews.