Greater London · England
Sand mastic for sash & case windows in East Finchley, Greater London
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in East Finchley and across Greater London. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Cement or filler used on old window joints that has cracked
- Mastic that needs renewing before redecorating
- Crumbling sand mastic round a window
Honest limits
We’ll always be straight with you, so here’s what new sealant won’t do:
- Sash cords, weights and draught-proofing of the sashes
- Decayed frames that need repair
- Cracked or broken glass
If in doubt, call 0345 464 0079 or drop us an email and we will say what we think before booking.
What we seal
- Timber door frames
- Stone surrounds
- Period & listed homes
- Sash and case windows
- Tenement windows
- Brick reveals
Sand mastic in East Finchley
Sand mastic is the traditional way to point the gap between a timber window frame and the stone or brick around it. It’s made from sand and a linseed-oil-based binder, applied by hand. On older homes, it suits the building far better than silicone. We work on tenement windows, sash and case windows and timber door frames, and common reasons people get in touch are patchy fillers round a sash window and open joints round the window box.
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, letting in draughts and water.
You’re covered for a year from the day we finish. If there’s a problem with it, please ring 0345 464 0079 or send us an email.
- Location
- East Finchley (N2, N3, NW11)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quote
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Places near East Finchley
Also in East Finchley
Sand mastic in East Finchley: local notes
Historic houses like Heath Hall (about 1.1 miles south) are a reminder that the area around East Finchley has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Managing a site like Holy Trinity CofE Primary School? Then its window and door frames need their mastic kept sound, just like a home’s. Homes close to Church of the Holy Trinity include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
East Finchley is about 5 miles north of Marylebone, in Greater London. For sand mastic in and around East Finchley, it’s easy to get a quote: please ring 0345 464 0079 or send us an email. We are based in Crawley and cover Greater London, East Finchley included. Our Greater London coverage runs to 764 places, and East Finchley is one of them. There’s also a page for London, roughly 7 miles from East Finchley.
All of N2, N3 and NW11 is within our area for sand mastic. Local streets include Oak Lane, Maya Road and High Road, and we cover them all. With the A1 close by, East Finchley is easy for our applicators to reach for sand mastic. Neighbouring places we cover for sand mastic include Hampstead Garden Suburb (1 mile south-west), Fortis Green (1 mile east), Temple Fortune (1 mile south-west), Muswell Hill (1 mile east) and Golders Green (2 miles south-west). We also work in nearby towns such as London (7 miles south-east), City of Westminster (5 miles south), Marylebone (5 miles south), Kensington (6 miles south), St Pancras (5 miles south-east) and Shoreditch (6 miles south-east).
Around East Finchley
Locally, jobs take us to homes and businesses close to Tollington School, Francis Skaryna Belarusian Library and Museum and Bishop Douglass School Finchley and the streets around them. Also close by are Lyttelton Playing Fields (0.5 miles south) and The Bald Faced Stag pub (0.5 miles east). For rail, the closest station is New Southgate station, about 2.2 miles north-east of the centre. Well-known places in the area include Grand Arcade (1.6 miles north) and Jewish Museum - Finchley (0.7 miles north-west). For a walk, there’s Highgate Hill and Long Lane Pasture.
Why deal with it now?
Draughts round a sash window aren’t always the sashes. Gaps between the frame and the wall can be just as bad and new mastic seals them. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in East Finchley, the repair is bigger than a sealant job.
Every job is a little different, so each one gets its own quote. The number of joints, how easy they are to reach and the sealant needed all play a part.
Why choose Mr Mastic in East Finchley
- Neat joints and a tidy finish
- Homes, businesses and hotels
- A 12-month guarantee on all work
- Rated 4.9 stars on Google
Take a look at how sealant jobs are priced and what customers say.
What we do, step by step
There’s no need to move everything out before we come, only the area right around the joints. We protect the rest, and the job takes a few hours per window, depending on the condition of the joints for a typical job. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- 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.
- The finish is dressed so it sits neatly against the stone or brick.
Preparing for the visit
- Mention any tricky access
- Keep children and pets away from the work area
- Tell us about any water getting in
Ask for a quote
The more we know about the job, the more useful the quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Related advice
Your questions about sand mastic in East Finchley
Can parking be tricky for a visit in East Finchley?
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 you cover East Finchley for sand mastic?
Yes. Our work covers London and the South East, and East Finchley is part of that. Just phone 0345 464 0079 or send us an email with a few details of the job, and we’ll send you a clear quote.
How long will you be here?
As a guide, most jobs take anything from a few hours to a full day, depending on how many windows. Larger jobs naturally take longer, and we’ll tell you how long to expect.
Can you replace silicone on a period window with sand mastic?
Often, yes. Once the silicone is out and the joint prepared we point it with sand mastic.
Do you work for landlords and businesses?
Yes. As well as householders, we work for landlords, agents, businesses and hotels.
What’s sand mastic made of?
It’s sand mixed with a linseed-oil-based binder for the joint between timber frames and masonry.
Can new sealant go over the old?
No. Fresh sealant doesn’t stick to old sealant, and it traps any mould or water underneath. We remove it all first.
Will you leave a mess?
No. The area is protected while we work and cleaned up afterwards.
How the job changes by surface
Timber door frames
A neat sand mastic joint round a front door suits a period home.
Brick reveals
Brick reveals round timber windows are often pointed with sand mastic. It gives a traditional finish.
Signs you need sand mastic in East Finchley
Age is the main cause. Sand mastic is a maintenance item like any pointing, depending on exposure and upkeep.
People generally contact us when they notice something like this:
- Draughts and rain around sash boxes
- Old sand mastic that has cracked, crumbled or fallen out
- Gaps round a timber door in stone or brick
- Weathered mastic on the most exposed windows
As a London address, East Finchley can be tricky for parking: let us know about parking bays, permits or a driveway.
What your quote should include
- Who turns up on the day
- What preparation is included
- Whether they’re fully insured
- The length of the guarantee
Can I do it myself?
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.
A DIY attempt does not rule out a professional job. We cut it out and start again.
Looking after it afterwards
A little care helps the new joints last. Our advice:
- Look over the window mastic once a year
- Go gently near the mastic when preparing windows
- Leave the new mastic unpainted
- Have rotten timber repaired before new mastic goes in
Do not touch or press the mastic while it hardens. It skins over quickly but needs longer to fully harden.
Good mastic helps keep the frame dry. Once it fails, water can sit against the timber and timber that stays wet can rot.