Greater London · England
Window Mastic in Northolt
Window and door frames in Northolt need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Whistling draughts around closed windows
- Draughty joints inside around the window
- Cracked or shrunken mastic around the frame
Window mastic for homes and businesses in Northolt
Mr Mastic’s applicators have more than 20 years’ experience with window and door sealants. We’re ARBOMaster approved and fully insured, and every job is covered by a 12-month guarantee. We work on aluminium frames, window sills and composite doors, and the jobs we see most are a bead that doesn’t match the frame and water coming in at the bottom corners of a door.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease generally says who is responsible for the windows, so it’s worth checking before booking, and access in Northolt is something to talk through when you book.
We stand behind the work with a one-year guarantee, so you’re covered after we’ve gone.
- Place
- Northolt (UB5, UB6)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
What happens on the day
The work is kept neat and contained to the joints we’re treating, so you can carry on as normal. The job normally takes 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. In a London area like Northolt, the main things to plan are parking and access: let us know about parking, the floor we will be working on and any lift or shared entrance.
- First, we go round the frames with you and agree the list.
- The old mastic is cut out and scraped back to clean surfaces.
- Where the gap is deep, backing rod goes in first.
- The new sealant goes on in white, brown, anthracite grey, black or clear to suit.
- Every joint is tooled smooth and checked before we leave.
Before we arrive
- Mention any tricky access
- Let us know if you’ve seen damp or leaks
- Let us know about earlier repairs to the joints
How to get a quote
If you’re in Northolt and need window mastic, ring 0345 464 0079 or drop us an email. Tell us what the problem is and where, and we will agree the price before any work begins.
Read more
DIY sealant or a professional job?
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.
What a professional job adds is preparation and the right product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is, then guaranteed for a year.
Northolt homes and the weather
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 Northolt Manor (about 0.3 miles south) are a reminder that the area around Northolt 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.
Rented homes near Northolt Park 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. Northolt is in London, so parking needs planning: let us know about parking bays, permits or a driveway. Managing a site like Willow Tree Primary School? Then the mastic around its windows and doors needs looking after like any other building’s.
Northolt is about 2 miles south-west of Harrow, in Greater London. Jobs in Northolt get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Across Greater London, we cover 764 places, and Northolt is one of them. For nearby work, see our London page, about 12 miles away.
Work in UB5 and UB6 is quoted and booked the same way as anywhere else. That includes homes and businesses on Church Road, Eastcote Lane North and Tenby Gardens. We also cover the places around Northolt: South Ruislip (1 mile north-west), Greenford (1 mile south-east), South Harrow (1 mile north-east), Yeading (2 miles south-west) and Yiewsley (2 miles south-west). Further out, we also cover London (12 miles east), City of Westminster (10 miles east), Marylebone (10 miles east), Kensington (8 miles south-east), St Pancras (11 miles east) and Shoreditch (13 miles east).
Local landmarks in Northolt
Around Northolt, our work takes us to homes and buildings near Northala Fields, The Greenwood Public House and Northolt High School. The nearest railway station is Northolt Park station, roughly 0.7 miles north-east of the centre. Nearby you will also find Heath Robinson Museum (3.1 miles north) and Clementine Churchill Hospital (2 miles north-east). Green spaces nearby include Islip Manor Meadows and Northala Fields.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. A few tips:
- Keep paint off silicone joints
- Repaint timber before it’s bare
- Make sure the drainage slots are not blocked
- Avoid blasting the frames with a pressure washer
Wipe the frames with soapy water when you clean the windows, and keep solvents and harsh chemicals off the joint.
Water gets in quietly when mastic fails. Often the first sign is a damp patch inside or flaking paint on the reveal. Catching it early keeps the fix to a reseal.
Surface by surface
uPVC windows
Plastic frames move a lot between a hot afternoon and a cold night, so we use a flexible, low-modulus sealant. We match white, brown, anthracite grey and black frames.
Timber windows & doors
Older timber windows in stone or brick can suit sand mastic rather than modern sealant. We can talk through the options.
Also near Northolt
Other services in Northolt
Why it’s worth doing now in Northolt
Once mastic fails, rain can get between the frame and the wall. Left long enough, it can stain inside walls, spoil plaster and rot wooden frames. A reseal is a much smaller job. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we will go through it with you.
Why book with us
- Neat joints and a tidy finish
- Approved under the ARBOMaster scheme
- Trusted Arbo and Everbuild sealants
- Every job guaranteed for a year
Take a look at how sealant jobs are priced or what customers say.
How we quote for window mastic
Some jobs are bigger than they look, and some smaller. The main factors:
- The number and length of the joints
- Whether the work is at height
- The old material and how stubborn it is
- The product the joint needs
The cost depends on the size of the job, how hard the old material is to remove and access to the work. We give a clear quote before any work starts.
What to tell us for a quote
Before you ask for a quote, have a think about:
- Where the job is, and your postcode
- The rough size of the job
- What the problem is, such as mould, gaps, leaks or cracking
- Pictures of the joints, sent by email
To get a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. You will have a clear quote before we start.
For landlords and businesses
Whether it’s one flat or a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
Failed sealant is one of the commonest items on a check-out report. Several properties can go on one quote.
Questions from Northolt
I let a flat near Northolt Park station. Can you help?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. Just call 0345 464 0079 or send us an email with the address and what needs doing, and we will give you a clear quote.
Is parking a problem for a job in Northolt?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
How long before the joint can be used?
Many sealants skin over quickly but take longer to cure fully. We’ll tell you how long to leave the joint.
Are you an approved applicator?
Yes. We’re an ARBOMaster approved applicator, which is run for the Arbo sealant brand.
Do you come to Northolt?
Yes. From our base in Crawley, we cover South East England, London and all of Scotland, and that includes Northolt.
How long does it take to reseal the windows on a house?
That depends on the number of frames, how they’re reached and the state of the old mastic. You’ll know the timing when we quote.
Will new mastic stop draughts?
It will if the frame joint is the problem. We find where the air is coming from before we reseal.
How do I get a quote for window mastic in Northolt?
There’s no set price, as it depends on the job: its size, the old material, access and the product needed. We agree the price before any work begins.