Greater London · England
Muswell Hill Window Mastic
Window mastic for Muswell Hill, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Old mastic that has gone black or come away
- Gaps between the frame and the inside reveal
- Sealant in the wrong colour for the frame
What happens on the day
Every visit runs the same way: we check the joints, mask and protect the surrounding surfaces, carry out the job and tidy away. It generally takes most of a day for a typical house, less for a few frames. In Muswell Hill, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- First we look at every frame and agree the list.
- We remove the old mastic and clean the frame and the wall.
- We fit backing rod in deep gaps so the sealant is the right depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Every joint is checked before we leave.
How to prepare
- Let us know about earlier repairs to the joints
- For indoor joints, keep the area dry beforehand if you can
- Mention any tricky access
Ask for a quote
There’s no standard price list. Instead, your job gets its own clear quote. To get started, ring 0345 464 0079 or send us an email.
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About our window mastic in Muswell Hill
Most frames have an outside joint and an inside one. The external joint is the weather seal; the internal joint closes the gap to the plaster and stops draughts. Either or both can be done. We work on uPVC windows, patio & French doors and timber windows & doors, and common reasons people get in touch are leaking joints at the ends of sills and mastic that has split away from the wall.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease usually says who is responsible for the windows, so it’s worth checking before booking.
Each job carries a 12-month guarantee, large or small.
- Location
- Muswell Hill (N10, N2, N8)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Muswell Hill: your questions answered
I let a flat near Alexandra Palace station. Can you help?
Yes, landlords and agents are among the people we work for. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Do you cover Muswell Hill for window mastic?
Yes, Muswell Hill is within the area we cover. We work across London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job, and we will give you a clear price.
What sealant do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. We use products from Arbo and Everbuild.
Can I add another job to the visit?
Yes, we can. More than one area can be quoted together.
What information do you need?
Just the basics: the address or postcode, what’s wrong and any access issues. After that, simply call 0345 464 0079 or email us.
Do you do commercial work?
Yes. Larger jobs can be planned room by room or area by area to suit the site.
Can you do the inside joint as well?
Yes. Indoors, we seal between the frame and the plaster or reveal.
Will new mastic stop draughts?
Yes, where the draught is at the frame edge. We find where the air is coming from before we reseal.
How we quote for window mastic
There’s no set price list, because jobs vary so much. The quote depends on:
- How easy the joints are to reach
- The number of rooms or windows
- The product the joint needs
- The old material and how stubborn it is
The cost depends on the size of the job, how hard the old material is to remove and how easy the joints are to reach. We give a clear quote before any work starts.
What to tell us for a quote
When you contact us, these details help:
- The type of property
- How we’d reach the joints
- If someone has resealed it before
- A few photos by email, if you can
For a quick quote, get us on the phone, or email us if that’s easier. Tell us about the joints that need doing and we will talk you through the work.
Work for landlords, hotels and businesses
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.
Mouldy or split sealant often shows up at the end of a tenancy, and it’s quick to put right between tenancies. We can quote for more than one property at once.
When it isn’t the sealant
It helps to know what we can’t do too:
- Draughts through the window seals rather than the frame
- A failed sealed unit that has misted up
- Broken hinges, locks or handles
If in doubt, call 0345 464 0079 or drop us an email and we will say what we think.
What we seal
- Window sills
- Aluminium frames
- Patio & French doors
- Composite doors
- uPVC windows
- Timber windows & doors
Should I try it myself first?
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it doesn’t work out, we can still put it right.
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Places near Muswell Hill
Other services in Muswell Hill
What we’re called out for in Muswell Hill
Mastic ages in the weather. Sunlight dries the surface out, and over the years it loses its give, cracks and comes away.
People normally contact us after spotting something like this:
- Untidy mastic left by window fitters
- Old mastic that has gone black or come away
- Gaps between the frame and the inside reveal
- White mastic on grey or black frames
Rented homes near Alexandra Palace station change hands often, and cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
Comparing quotes
- How long to leave it before use
- Is the old sealant removed completely?
- What product goes in the joint
- How the joint is cleaned and prepared
Frames and glazing around Muswell Hill
Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Athlone House (about 1.6 miles south-west) nearby, there’s older building stock in the area around Muswell Hill as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
Muswell Hill is in London, so parking needs planning: let us know about parking bays, permits or a driveway. Schools such as Muswell Hill Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s.
Muswell Hill is about 2 miles east of Finchley, in Greater London. Muswell Hill gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Our area takes in 764 places across Greater London, from the larger towns to small villages. We also work in London, around 7 miles away.
Jobs for window mastic in N10, N2 and N8 is quoted and booked the same way as anywhere else. Local streets include Cecil Road, The Avenue and Elgin Road, and we cover them all. With the A504 close by, Muswell Hill is simple for us to get to for window mastic. We also cover the places around Muswell Hill: Fortis Green (1 mile west), Hornsey (1 mile east), Crouch End (1 mile south-east), East Finchley (1 mile west) and Highgate (1 mile south). Within a short drive, we also cover London (7 miles south), City of Westminster (5 miles south), Marylebone (5 miles south), Kensington (7 miles south), St Pancras (5 miles south) and Shoreditch (5 miles south-east).
Near you in Muswell Hill
Locally, jobs take us to homes and businesses close to Tollington School, Alexandra Park and Fortismere School. For rail, the closest station is Alexandra Palace station, roughly 1.1 miles north-east. Well-known places in the area include The Mall Wood Green (1.5 miles east) and Kenwood House (1.8 miles south-west). Not far away are Glebelands Local Nature Reserve and Darland's Lake.
Why it’s worth doing now in Muswell Hill
A quick bead over the top of old mastic looks like an easy fix, but it won’t grip old, dirty sealant. It peels before long, and water still gets in behind. Proper resealing starts with removing the old joint. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Muswell Hill, the repair is bigger than a sealant job.
Every job is a little different, so each one gets its own quote. Size, access and the product the joint needs all make a difference, and we’ll explain the quote if you ask.
Why choose Mr Mastic in Muswell Hill
- Tidy, careful work
- ARBOMaster approved applicator
- A 12-month guarantee on all work
- Old sealant always removed completely
Take a look at what affects the cost or what customers say.