Greater London · England
Sand mastic for sash & case windows in Hampstead, Greater London
Sand mastic across Hampstead and nearby, with old sealant always removed completely and a 12-month guarantee.
- Patchy fillers round a sash window
- Weathered mastic on the most exposed windows
- Old sand mastic that has cracked, crumbled or fallen out
What the job involves on each surface
Stone surrounds
Stone surrounds suit sand mastic well. It finishes to look like part of the surround.
Tenement and terrace windows
Rows of sash windows on tenements and terraces often need renewing together. We can do one window or several.
Sand mastic in Hampstead, done properly
A silicone bead around a sash window can look out of place and does not suit the building. Sand mastic gives a finish that matches the age of the house and we can swap the silicone for it. Common call-outs are for failed mastic on an exposed elevation and gaps between timber frames and stone or brick, on timber door frames, sash and case windows and stone surrounds.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. Over the years, the sealant around them shrinks, cracks and pulls away, which is when draughts and damp patches appear in homes in Hampstead.
There’s a 12-month guarantee on every job.
- Where
- Hampstead (NW3, NW6, NW11, N2)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quote
- A clear price before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
For landlords and businesses
We work for landlords and letting agents as well as homeowners. Sealant work between tenants keeps a property looking cared for.
If you manage several properties in or around Hampstead, jobs at different addresses can go on one quote. Just tell us the addresses and what each one needs, and photos by email help.
DIY versus a professional finish
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
What sealant work cannot fix
We’d rather tell you now than do work that won’t last, so these are the limits:
- Sashes that rattle, stick or will not open
- Decisions on consent for listed homes
- Decayed frames that need repair
If you’re not sure, just phone 0345 464 0079 or drop us an email and we will give you a straight answer before you book.
Where we work in Hampstead
- Period & listed homes
- Tenement windows
- Sash and case windows
- Timber door frames
- Brick reveals
- Stone surrounds
Places near Hampstead
Other services in Hampstead
Do you need sand mastic in Hampstead?
Most of it is simply age. Sand mastic is a maintenance item like any pointing and how long it lasts depends on the weather it faces.
Signs it’s time to call us include:
- Gaps round a timber door in stone or brick
- Draughts and rain around sash boxes
- Modern sealant on a period surround
- Open joints round the window box
If you let a flat or house near Finchley Road & Frognal station, older sash windows in a rental need their mastic kept sound to keep the weather out.
Comparing quotes
- Which colour the sealant will be
- Whether they seal over old material or remove it
- What the cure time is
- What happens if they find a problem under the old sealant
What sand mastic looks like in Hampstead
Historic houses like Fenton House (about 0.4 miles north) are a reminder that the area around Hampstead has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic. 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.
For an older house near a landmark such as St John-at-Hampstead church, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. Hampstead is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Hampstead is about 3 miles north-west of City of Westminster, in Greater London. From the centre of Hampstead to the outskirts, sand mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Hampstead is one of 764 places in Greater London we cover for sand mastic.
Jobs for sand mastic in NW3, NW6, NW11 and N2 works the same way as everywhere else we cover. Whether your property is on Hampstead High Street, New End Square and The Mount Square or a nearby road, our applicators can take on the job. Main roads around Hampstead include the A1 and A502. We also cover the places around Hampstead: Greenhill (1 mile north-east), West Hampstead (1 mile west), Fortune Green (1 mile west), Vale of Health (1 mile north) and South Hampstead (1 mile south). Larger places within reach include London (5 miles south-east), City of Westminster (3 miles south-east), Marylebone (3 miles south-east), Kensington (4 miles south), St Pancras (3 miles south-east) and Shoreditch (5 miles south-east). Being one of Greater London’s larger places, Hampstead has homes, rented property and businesses of every kind.
Near you in Hampstead
Locally, jobs take us to homes and businesses close to South Hampstead High School, Kilburn Grange Park and St Anthony's Preparatory School and the streets around them. Also close by are King William IV Public House (less than half a mile north-east) and Cecil Sharp House (1.7 miles south-east). There’s a railway station in Hampstead itself: Finchley Road & Frognal station. Well-known places in the area include Isokon Gallery (0.8 miles east) and New End Hospital (within half a mile north). The countryside around Hampstead includes Belsize Wood and The Long Water.
What happens on the day
Once we’re on site, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. After that, the work takes anything from a few hours to a full day, depending on how many windows. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Hampstead. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Large voids are packed out first, so the mastic isn’t too thick.
- Sand mastic is mixed and applied by hand, then shaped to the joint.
- We dress the surface so it sits neatly against the masonry.
Before we arrive
- Clear items away from the joints we are working on
- On commercial sites, let us know about site rules
- Mention any parking rules near the property
Getting a quote
There’s no standard price list, because every job is different. Instead, we give you a clear price for your job. To get started, phone 0345 464 0079 or send us an email.
Related advice
FAQs for Hampstead
Can you do sand mastic in Hampstead?
Yes, Hampstead is within the area we cover. Our work covers London and the South East. You can ring 0345 464 0079 or send us an email and let us know what needs doing, and we’ll send you a clear quote.
Can parking be tricky for a visit in Hampstead?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Will you leave a mess?
We keep the work tidy. Nearby surfaces are protected.
Do the sealants smell?
Possibly a little. It fades as the sealant cures, and ventilation helps.
Can old silicone round a sash window be swapped for sand mastic?
Usually, yes. With the silicone removed and the joint cleaned, sand mastic is applied by hand.
Does someone need to be in?
It depends on the job. Inside work needs someone to give us access.
What exactly is sand mastic?
A traditional pointing material made from sand and a linseed-oil-based binder for the joint between timber frames and masonry.
Is consent needed for window work on a listed home?
Yes, it’s worth checking. Ask your local planning authority whether consent is needed for work on a listed home or in a conservation area.
What affects the quote in Hampstead
You’ll get a clear quote before work begins. It takes into account:
- How many areas need sealing
- Whether the work is at height
- Whether old sealant or filler has to be cut out
- Any working-time requirements on site
Leaving a failed joint normally makes the job bigger, not smaller, because water and mould keep working on it. If you’re not sure whether it needs doing, ring 0345 464 0079 or send us an email and we will give you an honest view and a quote.
What to tell us for a quote
To make quoting easier, please include:
- Any access issues, like height or stairs
- Pictures of the joints, sent by email
- Where the job is, and your postcode
- What’s wrong with the joints now
Every job is quoted individually, so the first step is telling us about yours. Just phone 0345 464 0079 or email us with the details and send pictures if you have them.