Greater London · England
Window & door mastic in East Finchley, Greater London
Problem with your window and door frames in East Finchley? We cut out the old, prepare the joints and apply the right sealant, with a one-year guarantee.
- Mastic that has split away from the wall
- Mastic that’s falling out in pieces
- Untidy mastic left by window fitters
Window mastic for homes and businesses in East Finchley
Whether it’s one leaking patio door or every frame on the house, the work is priced before anything is done. To get one, ring 0345 464 0079 or email us with the number of frames and any access details for window mastic in East Finchley. If you are dealing with mastic that’s falling out in pieces and whistling draughts around closed windows, we can put it right, on timber windows & doors, aluminium frames and patio & French doors alike.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. The mastic around them dries out and cracks with age, letting in draughts and water.
Big or small, you get the same 12-month guarantee.
- Place
- East Finchley (N2, N3, NW11)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quote
- A clear price before work begins
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Landlord and commercial work in East Finchley
Mouldy or split sealant often shows up at the end of a tenancy. We can quote for more than one property at once.
In hotels, rooms out of use cost money, so we plan the work room by room. We have worked in hotels as well as homes and businesses.
Keeping the joints in good condition
Simple care keeps the joints in good condition. Our advice:
- Keep timber frames painted
- Do not aim a pressure washer at the joints
- Do not use solvent cleaners on the joint
- Don’t paint over the silicone
Check the drainage slots in the frames are not blocked, so rain drains out rather than building up at the sealant.
Look out for the warning signs: split or missing mastic, gaps, damp patches inside or black mould on the reveal. Any of these is worth a call.
How the visit works
Before we leave, we go over the finished joints with you. The work normally takes a few hours for a few frames, or a day or more for a whole house, depending on the amount of work. 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 how each frame can be reached safely.
- All the failed sealant is cut away.
- The surfaces are cleaned and left dry, and primed where the sealant calls for it.
- Deep voids are backed, then the sealant is gunned in.
- We tool the joint so water runs off, then clear up.
How to prepare
- Keep children and pets away from the work area
- Try not to wet indoor joints just before the visit
- Let us know about parking restrictions
Get a quote
Need a quote? Please phone 0345 464 0079 or send us an email and tell us about the job. We’ll explain what we’d do and send you a clear quote before we start.
Advice
Why it’s worth doing now in East Finchley
Failed mastic is not a reason to replace sound windows. If the frames and glass are in good order, resealing the joints is often all that’s needed. If we find failed glass units or worn seals, we’ll tell you. In a London flat, a failed joint rarely stays your problem alone: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
Commercial jobs are quoted on the same basis as homes: how much there is to do, how we reach it and what it needs. Ask us for a quote and we will go through it with you.
Why East Finchley customers choose us
- Neat joints and a tidy finish
- Sanitary silicone with an anti-fungal additive in wet areas
- Arbo and Everbuild products
- Every job guaranteed for a year
Take a look at our cost guide and customer reviews.
When something else is needed
We will not take on work that won’t last, so here’s what sealant cannot put right:
- A failed sealed unit that has misted up
- Faulty window hardware
- Soft or decayed wood in the frame
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
- Patio & French doors
- Composite doors
- uPVC windows
- Window sills
- Timber windows & doors
- Aluminium frames
East Finchley: your questions answered
I let a flat near New Southgate station. Can you help?
Yes, rental work is part of what we do. You can phone 0345 464 0079 or send us an email with the address and a few details, and we will give you a fixed price before we start.
Can parking be tricky for a visit in East Finchley?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. The visit is then planned around what’s available.
Where is Mr Mastic based?
We work from Crawley. Our applicators cover East Finchley.
Do you cover East Finchley?
Yes. From our base in Crawley, we cover South East England, London and all of Scotland.
How long does it take to reseal the windows on a house?
It depends on access, the old mastic and the size of the frames. You will know the timing when we quote.
Should I try DIY first?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Do you guarantee window mastic?
Yes, with our one-year guarantee. A yearly look at the joints helps them last.
Do you have insurance?
Yes. Mr Mastic is fully insured.
Different surfaces, different methods
Timber windows & doors
Where timber has rotted at the joint, it needs repairing first. We’ll point out any rot we find, as that is a job for a joiner.
Window sills
Where a sill meets brick or render, the ends often crack first. A tight seal at each end keeps rain out of the wall.
Windows and doors in East Finchley
The South East is one of 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 London conversions and blocks, the lease decides who is responsible for the frames, so check that before booking.
If you let a flat or house near New Southgate station, renewing tired window mastic between tenants heads off draught and damp complaints. In the older streets around Church of the Holy Trinity, the joint between an old wall and a newer frame is generally the first place rain gets in. Schools such as Holy Trinity CofE Primary School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
East Finchley is about 5 miles north of Marylebone, in Greater London. We carry out window mastic for homeowners, landlords and businesses in East Finchley and nearby. East Finchley is one of 764 towns and villages in Greater London where we work. We also work in London, about 7 miles from East Finchley.
Postcode districts we cover here for window mastic: N2, N3 and NW11. Whether your property is on Oak Lane, Maya Road and High Road or anywhere close by, our applicators can take on the job. Main roads around East Finchley include the A1. We also cover the places around East Finchley: 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). Within a short drive, we also cover 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).
Local landmarks in 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. You’ll also find 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, roughly 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.
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.