Greater London · England
Sand Mastic in Belsize Park
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for Belsize Park, backed by a one-year guarantee. Call for a quick quote.
- Mastic round period door frames that has failed
- Wind and rain getting in round a sash window
- Open joints round the window box
Sand mastic in Belsize Park
Silicone on a period window often looks wrong and is not always the right material. Sand mastic is the traditional choice and we can swap the silicone for it. We work on sash and case windows, stone surrounds and timber door frames, and the jobs we see most are window mastic to renew ahead of painting and draughts and rain around sash boxes.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Location
- Belsize Park (NW3, NW5, NW1)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
When it is not the sealant
New sealant cannot fix everything, and we’d rather say so up front. It will not solve:
- Decayed frames that need repair
- Masonry that needs repairing
- Decisions on consent for listed homes
If you’re not sure, just call 0345 464 0079 or email us and we’ll give you a straight answer before you book.
What we seal
- Stone surrounds
- Timber door frames
- Sash and case windows
- Brick reveals
- Period & listed homes
- Tenement windows
Also near Belsize Park
What else we do in Belsize Park
Can I do it myself?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Quotes for sand mastic in Belsize Park
Every job gets its own quote. These are the things that affect it:
- How many areas need sealing
- Any mould that needs treating
- Any working-time requirements on site
- Which sealant suits the joint
No two jobs are quite the same, so we quote each one individually. Size, access and the product the joint needs all play a part.
What we need to know
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- If someone has resealed it before
- The address or postcode of the job
- Pictures of the joints, sent by email
- Whether it’s a home or a business
Getting a quote is simple: let us know what needs doing and where and its rough size. A few photos by email make the job easier to understand, and we will come back to you with a quote.
What we are called out for in Belsize Park
Timber swells and shrinks with the weather. That movement opens up the mastic joint little by little.
Most people get in touch when they notice one of these:
- Draughty sash windows at the surround
- Old sand mastic that has cracked, crumbled or fallen out
- Open joints round the window box
- A silicone bead on a sash window that spoils the look
If you live in an older home near Church of St Mary the Virgin, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Questions to ask before booking
- What guarantee comes with the work
- Who turns up on the day
- What happens if the job turns out different
- How long to leave it before use
Landlords, agents and businesses in Belsize Park
From a single let to a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a 12-month guarantee.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
What happens on the day
Good joint work is mostly preparation, so that’s where we spend the time. Every joint is cleaned and dried before new material goes in. In total, it generally takes a few hours per window, depending on the condition of the joints. In Belsize Park, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.
- We start by checking each surround and agreeing the joints to renew.
- Old, loose mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- We dress the surface so it sits neatly against the masonry.
How to prepare
- Mention any leaks or damp you’ve noticed
- Let us know about earlier repairs to the joints
- Tell us if parking is tricky
Ask for a quote
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we’ll explain what’s involved.
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FAQs for Belsize Park
Can you do sand mastic in Belsize Park?
Yes, Belsize Park is within the area we cover. We work across London and the South East. You can ring 0345 464 0079 or send us an email and tell us what needs doing.
Is parking a problem for a job in Belsize Park?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Do I need permission for sand mastic on a listed building?
Yes, it’s worth checking. Your local planning authority can say if consent is needed for listed or conservation-area properties.
How much does sand mastic cost in Belsize Park?
The cost depends on the size of the job, access and how much old sealant has to come out. Call for a quick quote.
Is it worth trying it myself?
Sometimes. Preparation is everything: all the old sealant out, and a clean, dry joint. We can always put it right if it fails.
Can I paint the new mastic?
It’s traditionally left unpainted, as guidance on traditional windows advises. Talk to us before any painting near it.
Do you work for hotels and businesses?
Yes. Commercial and hotel work is a large part of what we do. We can talk about working times when we quote.
Can you replace silicone on a period window with sand mastic?
Often, yes. With the silicone removed and the joint cleaned we point it with sand mastic.
Keeping the joints in good condition
Simple care keeps the joints in good condition. We recommend:
- Look over the window mastic once a year
- Ask a joiner to look at soft timber first
- Take care around the mastic when scraping paint
- Leave the new mastic unpainted
When preparing windows for paint, take care around the mastic. It can be damaged by heavy scraping.
Gaps round a sash box let in draughts and rain. Left, the gap tends to get bigger.
What sand mastic looks like in Belsize Park
Historic houses like Keats House (about 0.8 miles north) are a reminder that the area around Belsize Park has older buildings as well as new. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
Belsize Park is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. Rented homes near South Hampstead station change hands often, and any sash windows need sound mastic to keep draughts and rain out.
Belsize Park is about 1 mile south-east of Hampstead, in Greater London. If you need sand mastic in Belsize Park, please ring 0345 464 0079 or send us an email for a quick quote. We’re based in Crawley and cover Greater London, Belsize Park included. Across Greater London, we cover 764 places, and Belsize Park is one of them.
Postcode districts we cover here for sand mastic: NW3, NW5 and NW1. Local streets include Eton Road, Lawn Road and Ornan Road, all of which we cover. We also cover Haverstock (1 mile north), Primrose Hill (1 mile south), South Hampstead (1 mile west), Swiss Cottage (1 mile west) and Chalk Farm (1 mile east). Larger places within reach include London (4 miles south-east), Kensington (4 miles south-west), Shoreditch (4 miles east), Walthamstow (7 miles north-east), Hoxton (3 miles east) and Whitechapel (4 miles south-east).
Around Belsize Park
We work in homes and buildings around The Washington pub, Primrose Hill and St. Mary's Town and Country School and the streets around them. Also close by are Cecil Sharp House (0.8 miles south-east) and St Paul's Church of England Primary School (less than half a mile south). The closest station to Belsize Park is South Hampstead station, roughly 0.7 miles west. Other landmarks nearby include Wellington Hospital (0.9 miles south-west) and O2 Centre (0.8 miles west). Green spaces nearby include Adelaide Nature Reserve and The Long Water.