Greater London · England
Sand mastic for sash & case windows in North End, Greater London
Sand mastic for North End and the surrounding area: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Crumbling sand mastic round a window
- Gaps round a timber door in stone or brick
- Weathered mastic on the most exposed windows
Aftercare tips
So the new joints stay in good condition:
- Avoid heavy scraping on the mastic joint
- Get any rot dealt with first
- Don’t paint over the new mastic
- Clear gutters so water doesn’t pour onto the windows
Avoid painting over the new mastic, which is the traditional advice. If you are redecorating, ask us first.
Good mastic helps keep the frame dry. Failed mastic lets water reach the timber and timber that stays wet can rot.
Sand mastic in North End, done properly
Sand mastic suits most period window surrounds. Newer frames usually get a flexible sealant instead and we will explain which is best for yours. If you have mastic dropping out of the joint and gaps where the frame meets the masonry, we can help, on brick reveals, stone surrounds and period & listed homes alike.
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 North End.
Whatever the size of the job, it’s backed by our 12-month guarantee.
- Location
- North End (NW3, NW11, N2)
- Wider area
- Greater London
- Cover
- One year on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
When it isn’t the sealant
Honest advice matters more to us than a booking, so here’s what sealant can’t fix:
- Broken panes
- 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 will give you a straight answer.
What we seal
- Sash and case windows
- Brick reveals
- Timber door frames
- Stone surrounds
- Period & listed homes
- Tenement windows
Windows and doors in North End
In a converted house or block, who looks after the windows depends on the lease, so check that before you book. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
As a London address, North End can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. For site and facilities teams at buildings such as The King Alfred School, the mastic around its windows and doors needs looking after like any other building’s.
North End is about 1 mile north of Greenhill, in Greater London. We carry out sand mastic for homeowners, landlords and businesses in North End and the surrounding area, as part of our work across Greater London. Our Greater London coverage runs to 764 places, and North End is one of them. We also work in London, about 6 miles from North End.
Here we cover the NW3, NW11 and N2 postcode area for sand mastic. You will find streets such as Sandy Road, Park Avenue and Platt's Lane, and we cover them all. North End is on the A502, which makes it straightforward to reach with everything needed for sand mastic. Other places close to North End include Vale of Health (1 mile south-east), Childs Hill (1 mile south-west), Golders Green (1 mile north-west), Greenhill (1 mile south) and West Hampstead (1 mile south). We also work in nearby towns such as London (6 miles south-east), City of Westminster (4 miles south), Marylebone (4 miles south-east), Kensington (5 miles south), St Pancras (4 miles south-east) and Shoreditch (5 miles south-east).
Near you in North End
We work in homes and buildings around The Old Bull and Bush pub, Childs Hill Park and The Henrietta Barnett School and the streets around them. The closest station to North End is Hampstead Heath station, roughly 1.1 miles south-east. A little further out are O2 Centre (1.4 miles south) and New End Hospital (0.7 miles south). The countryside around North End includes Turner's Wood and Darland's Lake.
Towns and villages near North End
Also in North End
Different surfaces, different methods
Stone surrounds
Stone surrounds suit sand mastic well. The finish blends with the masonry.
Tenement and terrace windows
Windows above ground floor need the right access. Tell us the height and we will confirm what’s needed.
Landlords, agents and businesses in North End
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
If you manage several properties in or around North End, several properties can go on one quote. Send us the addresses and the work at each.
The process
All our tools and materials come with us in the van, so there’s nothing for you to buy. Once we have agreed what’s being done, the area is protected and the work begins. Most jobs take a few hours for a single window, longer for several. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in North End. It helps if you can point us to a visitor permit or a bay close to the door.
- First we agree which joints need doing.
- Old mastic and any loose material are raked out.
- We pack any deep voids first.
- The sand mastic is mixed and pressed into the joint by hand.
- We dress the finish so it sits neatly against the masonry.
Preparing for the visit
- Clear the area around the work
- Mention if the joints have been sealed before
- Keep children and pets away from the work area
Get a quote
Asking for a quote is easy: let us know what needs doing and where. A few pictures by email make the job easier to understand, and we’ll come back to you with a quote.
Advice
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
If you’ve already had a go yourself, that is fine. We cut it out and start again, so tell us about it when you ask for a quote.
What we’re called out for in North End
Decorating can disturb tired mastic. It’s often found when windows are being prepared for paint.
These are the problems we’re asked about most:
- Weathered mastic on the most exposed windows
- Gaps round a timber door in stone or brick
- Window mastic to renew ahead of painting
- Old sand mastic that has cracked, crumbled or fallen out
Homes close to Church of St Alban the Martyr include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Questions to ask before you book
- What insurance they hold
- Who turns up on the day
- Whether VAT is included
- How hidden problems are handled
Common questions in North End
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 go on one quote. Just phone 0345 464 0079 or send us an email with the address and what needs doing, and we’ll send you a clear quote.
Is parking a problem for a job in North End?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
What information do you need?
Just the basics: where it is, what you’ve noticed and how we reach it. After that, simply call 0345 464 0079 or send us an email.
Do I need permission for sand mastic on a listed building?
Your local planning authority is the one to ask. They’ll tell you if consent is needed.
Can you match the sealant colour?
Most of the time, yes. We will tell you which colours the right product comes in.
What exactly is sand mastic?
Sand mastic is a traditional material for pointing round windows and doors. It’s made with sand and a linseed-oil-based binder.
Are you insured?
Yes. We are fully insured, with over 20 years’ experience in sealant work.
Which is right for my windows, sand mastic or modern sealant?
We’ll help you decide. Sand mastic suits many period homes and newer frames suit modern sealant.