Greater London · England
Vale of Health Sand Mastic
Professional sand mastic in and around Vale of Health, with every bit of old sealant taken out first and a 12-month guarantee.
- Draughty sash windows at the surround
- A silicone bead on a sash window that spoils the look
- Tired mastic found when preparing windows for paint
For landlords and businesses
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. We can quote for more than one property at once.
If you manage several properties in or around Vale of Health, jobs at different addresses can be quoted together. Send us the addresses and the work at each.
Sand mastic in Vale of Health
A silicone bead around a sash window can look out of place and isn’t always the right material. Sand mastic gives a finish that matches the age of the house and we can swap the silicone for it. We’re often asked to deal with window mastic to renew ahead of painting and cement or filler used on old window joints that has cracked, across period & listed homes, timber door frames and brick reveals.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first.
All of our work is guaranteed for twelve months, in Vale of Health and everywhere else we cover.
- Place
- Vale of Health (NW3)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
The process
There isn’t much for you to do on the day. Point us to the joints and we will get on with it. The work itself takes a few hours for a single window, longer for several from start to finish. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Vale of Health. A visitor permit or a nearby bay makes the visit run more smoothly.
- We look at the surrounds with you and agree the joints to renew.
- Old mastic and any loose material are raked out.
- Deep gaps are packed so the mastic sits at the right depth.
- The sand mastic is mixed and pressed into the joint by hand.
- The surface is finished to suit the stone or brick.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- Clear the area around the work
- For business premises, tell us about site rules or sign-in
Get a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is. When it suits you, phone 0345 464 0079 or drop us an email.
Advice
What sealant work cannot fix
To be straight with you, some problems need a different trade:
- Broken panes
- Planning or listed building consent (your local planning authority decides)
- Crumbling stone or brickwork round the window
Not sure which it is? You can call 0345 464 0079 or drop us an email and we’ll tell you honestly.
What we seal
- Stone surrounds
- Sash and case windows
- Timber door frames
- Tenement windows
- Brick reveals
- Period & listed homes
Frames and glazing around Vale of Health
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. In a converted house or block, who looks after the windows depends on the lease, so check that before you book.
Vale of Health is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. For landlords with property near Hampstead Heath station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
Vale of Health is about 1 mile north of Greenhill, in Greater London. Vale of Health gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a one-year guarantee. Our Greater London coverage runs to 764 places, Vale of Health among them. You can also see our page for London, about 6 miles away.
Work in NW3 works the same way as everywhere else we cover. Local streets include Well Road, Cannon Lane and Holford Road, all of which we cover. You’ll find Vale of Health on the A502, which makes it straightforward to reach. We also cover the places around Vale of Health: North End (1 mile north-west), Greenhill (1 mile south), Hampstead (1 mile south), West Hampstead (1 mile south-west) and Childs Hill (1 mile west). Further out, we also cover London (6 miles south-east), City of Westminster (3 miles south), Marylebone (3 miles south), Kensington (4 miles south), St Pancras (4 miles south-east) and Shoreditch (5 miles south-east).
Landmarks near Vale of Health
In Vale of Health, that means homes and buildings near St Vedasts School For Boys, South Hampstead High School and Hampstead Heath and the streets around them. Vale of Health’s nearest station is Hampstead Heath station, about 0.7 miles south-east of the centre. Nearby you will also find New End Hospital (less than half a mile south) and Montfichet's Tower (4.7 miles south-east). The countryside around Vale of Health includes Parliament Hill and Turner's Wood.
Why deal with it now?
Filling over old, loose mastic doesn’t last. We remove the loose material first so the new mastic stays put. Converted houses in London often have a bathroom above someone else’s living room, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Dealing with it early is far simpler.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Why Vale of Health clients choose us
- 180+ five-star Google reviews
- Homes, businesses and hotels
- More than 20 years in sealant work
- Full insurance on every job
Read what affects the cost and what customers say.
Places near Vale of Health
Also in Vale of Health
FAQs for Vale of Health
Can you help a landlord with a rental near Hampstead Heath station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. You can ring 0345 464 0079 or drop us an email with the details for a clear quote.
Is Vale of Health in your area for sand mastic?
Yes. Our work covers London and the South East, and Vale of Health is part of that. Just phone 0345 464 0079 or email us with a few details of the job, and we’ll send you a clear quote.
What should I tell you?
A short description and the location, with photos by email if possible. We will ask anything else we need to know.
Is the work guaranteed?
There’s a 12-month guarantee on every job, sand mastic included.
How long does the job take?
That depends on the amount of work, but as a guide it takes a few hours for a single window, longer for several. We will tell you when we quote.
What exactly is sand mastic?
It’s a mix of sand and a linseed-oil-based binder. It’s applied by hand and finished to sit neatly against the masonry.
Is sand mastic better than silicone for my windows?
That depends on your windows. On many period windows, sand mastic looks right and suits the building, while modern frames normally get a flexible sealant.
Can you replace silicone on a period window with sand mastic?
Yes. We remove the silicone and clean the joint before the sand mastic goes in.
Aftercare tips
Simple care keeps the joints in good condition. We recommend:
- Renew mastic before redecorating the windows
- Clear gutters so water doesn’t pour onto the windows
- Check the mastic when you check the paintwork
- Avoid patching sand mastic with silicone
Look at the mastic when you look over the windows. Small cracks are easier to deal with early.
Small cracks are a sign the mastic is ageing. Renewing it then is simpler than waiting until it falls out.
DIY sealant or a professional job?
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Signs you need sand mastic in Vale of Health
Over the years, sand mastic weathers. It hardens, cracks and starts to come away on the stone or timber.
Any of these means the joints need attention:
- Cracked mastic round a front door frame
- Failed mastic on an exposed elevation
- Open joints round the window box
- Draughty sash windows at the surround
If you live in an older home near Christ Church, the joint between an old wall and a newer frame is generally the first place rain gets in.
Questions to ask before booking
- How long the guarantee is
- Are they insured?
- Whether you can choose the colour
- Is the old sealant removed completely?