Greater London · England
Neasden Window Mastic
Window mastic for Neasden and the surrounding area: careful preparation, the right product and tidy work. Call for a quick quote.
- Cracked internal joints between frame and plaster
- Cold air getting in at the frame edge
- Leaking joints at the ends of sills
Window mastic in Neasden
Frames and walls don’t move together. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. That is why the joint needs a flexible, low-modulus sealant rather than something rigid. Common call-outs are for rain getting in at the frame or under the sill and gaps where the sill meets the wall, on patio & French doors, window sills and uPVC windows.
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, which is when draughts and damp patches appear in homes in Neasden.
There’s a 12-month guarantee on every job.
- Where
- Neasden (NW10, NW2, NW9)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Quote
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Why it’s worth doing now in Neasden
A cracked joint around a frame lets rain into the wall. Left long enough, it can stain inside walls, spoil plaster and rot wooden frames. Resealing now is a small job by comparison. In a flat in Neasden, 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.
Leaving a failed joint generally makes the job bigger, not smaller, as water and mould keep getting in. If you are not sure whether it needs doing, phone 0345 464 0079 or drop us an email for an honest opinion and a quote.
Why Neasden clients choose us
- White, clear, grey or coloured to suit, where the product allows
- Trusted Arbo and Everbuild sealants
- 180+ five-star Google reviews
- Colour picked to suit the job
Read what affects the cost and customer reviews.
Looking after it afterwards
How long the joints last depends on use and care. Here’s what we suggest:
- Keep paint and stain on wooden frames in good order
- Wash the frames with mild soapy water
- Keep solvents and bleach off the sealant
- Air rooms to keep condensation down around windows
Keep the new mastic undisturbed while it cures, following the cure time we give you. Do not point a pressure washer at the joints.
A failed joint lets water into the wall a little at a time. Often the first sign is a damp patch inside or flaking paint on the reveal. Catching it early keeps the fix to a reseal.
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The process
We keep the work tidy and contained to the area we’re working on, so you can get on with your day. Expect the work to take anything from an hour or two to a full day, depending on how many frames there are, and we explain the cure time before we leave. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. Mention any building rules, key holders or managing agents when you book.
- Each frame is looked over and we agree which ones need resealing.
- The old mastic is cut out and scraped back to clean surfaces.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
How to prepare
- Tell us about any water getting in
- For business premises, tell us about site rules or sign-in
- Mention any tricky access
Getting a quote
Want a quote for window mastic? Please call 0345 464 0079 or drop us an email and tell us about the job. You’ll know what we plan to do, and what it will cost, before any work begins.
Advice
Surface by surface
Composite doors
An exposed front door gets wind-driven rain. Those corners get the most care.
Window sills
Sills catch the water running down the glass, so the sill ends and the joint under the frame are vital. They’re cut out and resealed with exterior sealant.
Neasden questions
Can parking be tricky for a visit in Neasden?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Can you help a landlord with a rental near Brent Cross West station?
Yes. We work for letting agents and landlords as well as householders. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we will give you a clear quote.
Do you work on first-floor windows?
Yes, where it’s safe. For high or awkward windows, we’ll tell you what access is needed.
Can new sealant go over the old?
No. New silicone won’t bond to old silicone, and it traps any mould or water underneath. It all has to come out first.
Do you come to Neasden?
We do. Neasden is part of the area we cover, and the service is the same as everywhere else.
How long should I leave it?
Most sealants are touch-dry well before they’re fully cured. We will tell you how long to leave the joint before we leave.
Do you take out the old sealant first?
Yes. All of the old material is cut out and the joint cleaned before applying anything new.
Can I do it myself?
For a simple, easy-to-reach joint, a careful DIYer can do a reasonable job. Most DIY failures come from sealing over old material, wet joints or too much sealant.
Common problems we fix in Neasden
Joints that are too thin or too deep fail early. A thin smear across a wide gap has nothing to it, and a gap filled solid can’t flex. Backing rod sets the right depth.
The problems people normally mention when they call include:
- Black, perished sealant on frames
- Sealant in the wrong colour for the frame
- Cracked or shrunken mastic around the frame
- Gaps where the sill meets the wall
Schools such as Northview Junior and Infant School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
What your quote should include
- How much experience the applicator has
- Is VAT in the price?
- How long the guarantee is
- Whether the sealant suits the joint
How we quote for window mastic
You will get a clear quote before any work starts. It’s based on:
- Working hours on commercial sites
- The old material and how stubborn it is
- Whether there’s mould to deal with
- The number of rooms or windows
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first.
What we need to know
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- The problem you’ve noticed
- Where the job is, and your postcode
- If it’s domestic, commercial or a hotel
- If someone has resealed it before
For window mastic in Neasden, ring 0345 464 0079 or drop us an email. A short description of the job and where it is helps us quote, and you will get a clear quote before we start.
Landlord and commercial work in Neasden
Letting agents often deal with us directly. Tell us the address, the job and how access works and we’ll give you a quote.
Whether it’s one flat or a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
What window mastic looks like in Neasden
Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Fenton House (about 2.9 miles east) nearby, there’s older building stock in the area around Neasden as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
Letting a property close to Brent Cross West station? Then renewing tired window mastic between tenants heads off draught and damp complaints. Homes close to St Catherine's Church Neasden with St Paul include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Neasden is about 5 miles north-west of City of Westminster, in Greater London. We carry out window mastic for homes and businesses in Neasden and nearby. Our Greater London coverage runs to 764 places, and Neasden is one of them. London is on our list too, about 8 miles from Neasden.
All of NW10, NW2 and NW9 is within our area for window mastic, from the main roads to the quietest streets. Whether your property is on Dog Lane, High Road and Ilex Road or anywhere close by, our applicators can take on the job. Nearby, we also carry out window mastic in Brent Park (1 mile west), Church End (1 mile south), Willesden (1 mile south-east), Dollis Hill (1 mile north-east) and Willesden Green (1 mile south-east). Further out, we also cover London (8 miles south-east), City of Westminster (5 miles south-east), Marylebone (5 miles south-east), Kensington (4 miles south-east), St Pancras (6 miles east) and Shoreditch (8 miles east).
Local landmarks in Neasden
In Neasden, that means homes and buildings near Gladstone Park, The Swaminarayan School and Crest Boys' Academy. The nearest railway station is Brent Cross West station, roughly 1.3 miles north-east of the centre. Nearby you will also find Neasden Hospital (0.7 miles south-west) and London Designer Outlet (1.7 miles west). The countryside around Neasden includes Westbere Copse and Castlebar Hill.