Greater London · England
Kentish Town Window Mastic
Window mastic across Kentish Town and nearby, with old sealant always removed completely and a 12-month guarantee.
- Hard, cracked sealant around windows
- Cracked sealant at the sill ends
- White mastic on grey or black frames
About our window mastic in Kentish Town
Some gaps around frames are far deeper than they look. Filling it with sealant alone leaves a joint that cannot move properly, so deep gaps get backing rod first. The sealant then grips the two sides it should. If you’re dealing with gaps left after new windows were fitted and hard, cracked sealant around windows, we can help, on timber windows & doors, composite doors and aluminium frames 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, letting in draughts and water.
Your job is guaranteed for a year, as with all our work.
- Where
- Kentish Town (NW5, NW1, NW3)
- Region
- Greater London
- Cover
- One year on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
What happens on the day
All our tools and materials come with us in the van. Once we’ve agreed what’s being done, we protect the area and start. It normally takes a morning for a couple of windows and a door. In Kentish Town, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- We check each frame and agree which ones need doing.
- 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.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- Every joint is checked before we leave.
Before we arrive
- Try not to wet indoor joints just before the visit
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us about any previous sealing or DIY attempts
How to get a quote
There’s no standard price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To arrange one, ring 0345 464 0079 or drop us an email.
Read more
Leave it or put it right?
Failed mastic is not a reason to replace sound windows. Where the frames are sound, new mastic normally deals with draughts and leaks at the edges. Problems with the glass or gaskets are for a window company, and we’ll say so. In a flat in Kentish Town, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Rather than a set price list, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why us?
- We never seal over old sealant
- Neat joints and a tidy finish
- Arbo and Everbuild products
- An ARBOMaster approved applicator
See our cost guide or our reviews.
DIY sealant or a professional job?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
If you’ve already had a go yourself, that is fine. We remove it and do the joint properly, so just mention it when you contact us.
For landlords and businesses
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance.
If you manage several properties in or around Kentish Town, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and photos by email help.
When to call us in Kentish Town
Timber windows bring their own problems. Mastic painted over many times cracks with the paint, and the wood moves with damp as well as heat.
These are the problems we’re asked about most:
- Cracked internal joints between frame and plaster
- Draughts coming in around windows and doors
- Gaps left after new windows were fitted
- Black, perished sealant on frames
Managing a site like Holy Trinity and Saint Silas CofE Primary School? Then the mastic around its windows and doors needs looking after like any other building’s.
Comparing quotes
- Who does the work, and how experienced they are
- The length of the guarantee
- Whether all the old sealant comes out first
- What insurance they hold
Your questions about window mastic in Kentish Town
Is parking an issue for window mastic in Kentish Town?
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.
Can you do window mastic in Kentish Town?
Yes, Kentish Town is within the area we cover. We work across London and the South East. You can call 0345 464 0079 or drop us an email and tell us what needs doing.
Can you get sealant to suit coloured frames?
Yes. We can use white, brown, anthracite grey, black or clear.
Where do you work from?
Mr Mastic is based in Crawley. We cover Kentish Town and the rest of Greater London, along with the rest of our area.
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.
Will it make a mess?
Tidy work is part of the job. We protect what’s around the joints, and the area is left clean when we finish.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status.
What should I tell you?
Tell us what needs doing and where, plus pictures if you have them. We will ask anything else we need to know.
Window mastic in Kentish Town: local notes
Historic houses like Keats House (about 1.2 miles north-west) are a reminder that the area around Kentish Town 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. In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
If you live in an older home near Church of the Holy Trinity with St Barnabas, frames set in older brick or stone need a sealant that suits the wall as well as the frame. Kentish Town is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Kentish Town is about 2 miles east of Hampstead, in Greater London. For window mastic in and around Kentish Town, it’s easy to get a quote: please call 0345 464 0079 or email us. We cover Greater London from our Crawley base, Kentish Town included. Our area takes in 764 places across Greater London, large and small.
Jobs for window mastic in NW5, NW1 and NW3 works the same way as everywhere else we cover. Whether your property is on Eton Road, Oval Road and Regal Lane or anywhere close by, we can help. We also cover Chalk Farm (1 mile west), Camden Town (1 mile south-east), Gospel Oak (1 mile north), Primrose Hill (1 mile south-west) and Agar Town (1 mile south-east). Larger places within reach include London (4 miles south-east), Kensington (4 miles south-west), Shoreditch (3 miles south-east), Walthamstow (6 miles north-east), Hoxton (3 miles east) and Whitechapel (4 miles south-east).
Around Kentish Town
In Kentish Town, that means homes and buildings near Primrose Hill, Haverstock School and North Bridge House School. Also close by are The Hawley Arms (less than half a mile south) and Vaughan Williams Memorial Library (0.5 miles south). There’s a railway station in Kentish Town itself: Kentish Town West station. Nearby you’ll also find O2 Centre (1.6 miles west) and Montfichet's Tower (2.9 miles south-east). The countryside around Kentish Town includes The Long Water and Primrose Hill.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. Our tips:
- Keep paint and stain on wooden frames in good order
- Don’t use solvent cleaners on the joint
- Look round the frames every year or so
- Ventilate rooms so frames do not stay wet inside
Most silicone sealants will not take paint, so mention any painting plans before we start. There are paintable sealants for joints that need it.
Wet, windy weather is when failed mastic shows itself, but resealing works best in dry conditions. Dealing with it when you first notice a crack avoids chasing leaks through the wet months.
What the job involves on each surface
Composite doors
Draughts round the door leaf generally come from worn seals or adjustment, not the mastic. We will tell you if that is what we find.
Timber windows & doors
Older timber windows in stone or brick can suit sand mastic rather than modern sealant. We’ll tell you which suits your home.