Greater London · England
Window Mastic in Cockfosters
Window mastic in Cockfosters from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Cracked or shrunken mastic around the frame
- Leaking joints at the ends of sills
- Water coming in at the bottom corners of a door
DIY sealant or a professional job?
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
Window mastic in Cockfosters
Every window and door frame has a gap around it, and mastic is what closes it. When it cracks, hardens or pulls away, draughts and rain get in. The old mastic is removed and the joint resealed with a flexible exterior sealant. If you’re dealing with leaking joints at the ends of sills and cracked or shrunken mastic around the frame, we can help, whatever the surface.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. Over the years, the sealant around them shrinks, cracks and pulls away, letting in draughts and water.
Your job is guaranteed for a year, as with all our work.
- Place
- Cockfosters (EN4, N14)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
What affects the quote in Cockfosters
Every job gets its own quote. This is what makes a difference:
- Access and height
- When we can work, for business premises
- The size of the job
- Whether old sealant or filler has to be cut out
Commercial jobs are quoted on the same basis as homes: how much there is to do, how we reach it and what it needs, along with when we can work on site. Call for a quick quote and we will go through it with you.
What we need to know
When you call or email, it’s useful to know:
- Photos by email, if that is easy
- The problem you’ve noticed
- Where the property is
- How many joints, rooms or windows are involved
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints.
What we cannot put right
Some problems need a builder, plumber or other trade rather than us:
- A failed sealed unit that has misted up
- Soft or decayed wood in the frame
- A door that needs adjusting, rehanging or new seals
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think before booking.
What we seal
- Composite doors
- Window sills
- Aluminium frames
- Patio & French doors
- uPVC windows
- Timber windows & doors
Nearby places to Cockfosters
Also in Cockfosters
Different surfaces, different methods
Window sills
Stone and concrete sills have their own joints, including the one between the sill and the frame above. Those are sealed with a product suited to stone or concrete.
uPVC windows
The frame is cleaned with a product that will not harm the plastic, then the new bead is laid against the frame and the wall.
Questions from Cockfosters
Can parking be tricky for a visit in Cockfosters?
Parking in Cockfosters, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Do you work for landlords with property near New Barnet station?
Yes, landlords and agents are among the people we work for. Just ring 0345 464 0079 or send us an email with the address and what needs doing, and we’ll give you a clear price.
Can resealing stop a draught around my window?
If the draught is coming in around the frame, yes. If it’s through the window’s own seals or a hinge, that is a different fix, and we’ll say so.
Do you guarantee window mastic?
Yes, with our one-year guarantee. Keeping drainage clear and checking the joints yearly helps them last.
Do you hold any approvals?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
How long should I leave it?
That depends on the sealant used, so follow the cure time we give you.
How long will my window job take?
Allow a morning for a couple of windows and a door. Access and the amount of old mastic make the biggest difference.
Can you seal over the old sealant?
No, because it fails. We remove every bit of old sealant first.
How it works
At the end, we look at the finished work together. The visit itself generally takes most of a day for a typical house, less for a few frames, depending on the amount of work. In Cockfosters, flats, stairs and shared entrances are part of the routine. Mention any building rules, key holders or managing agents when you book.
- We check how each frame can be reached safely.
- All the failed sealant is cut away, along with any loose debris.
- 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.
- The joint is shaped to shed water and the area tidied.
Before we arrive
- Keep pets and children clear of the area while we work
- For business premises, tell us about site rules or sign-in
- Try not to wet indoor joints just before the visit
How to get a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is, and we’ll talk you through what we’d do. When it suits you, call 0345 464 0079 or email us.
Advice
Work for landlords, hotels and businesses
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
Why it’s worth doing now in Cockfosters
Draughts and leaks don’t always mean new windows. If the frames and glass are in good order, resealing the joints is often all that’s needed. Problems with the glass or gaskets are for a window company, and we’ll say so. In a flat in Cockfosters, failed sealant seldom stays inside your own four walls: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
What you pay reflects the work, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
Why choose Mr Mastic in Cockfosters
- Arbo and Everbuild products
- Domestic, commercial and hotel work
- Anti-fungal sanitary silicone in wet areas
- Sealant colour chosen to suit
Frames and glazing around Cockfosters
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. Historic houses like Wyllyotts Manor (about 3.4 miles north-west) are a reminder that the area around Cockfosters 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.
Homes close to Christ Church include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. Letting a property close to New Barnet station? Then sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. For site and facilities teams at buildings such as Trent CofE Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Cockfosters is about 1 mile east of Barnet, in Greater London. Anywhere in EN4, our applicators can take on window mastic. Cockfosters is one of 764 towns and villages in Greater London we cover. We also work in London, around 11 miles away.
Jobs for window mastic in EN4 and N14 is quoted and booked the same way as anywhere else. Whether your property is on Park Road, Grove Road and Bevan Road or anywhere close by, our applicators can take on the job. With the A111 close by, Cockfosters is simple for us to get to for window mastic. If you are just outside Cockfosters, we cover New Barnet (1 mile south-west), Hadley Wood (1 mile north-west), East Barnet (1 mile south), Oakwood (1 mile south-east) and Osidge (1 mile south-east). We also work in nearby towns such as London (11 miles south), City of Westminster (10 miles south), Marylebone (9 miles south), Kensington (11 miles south), St Pancras (9 miles south) and Shoreditch (9 miles south).
What’s near Cockfosters
Around Cockfosters, our work takes us to homes and buildings near The Cock Inn, Trent School Cockfosters and Belmont Open Space, among other places. Cockfosters’s nearest station is New Barnet station, roughly 0.8 miles west of the centre. Well-known places in the area include Francis Skaryna Belarusian Library and Museum (2.8 miles south-west) and Chase Farm Hospital (2.5 miles north-east). For a walk, there’s Covert Way and Darland's Lake.