Greater London · England
Window & door mastic in Harlington, Greater London
Our applicators work in Harlington on mastic around window and door frames, sills and patio doors. Old material cut out, joints cleaned and sealed neatly and every job guaranteed for a year.
- Cold air getting in at the frame edge
- Cracked sealant at the sill ends
- Water coming in at the bottom corners of a door
About our window mastic in Harlington
A cold draught around a closed window often comes from the frame edge. Resealing that joint can make a room feel noticeably less draughty and quietens the whistle on windy days. Where the air is getting in through the window itself, we’ll say so. We work on window sills, patio & French doors and aluminium frames, and the jobs we see most are black, perished sealant on frames and gaps where the sill meets 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 normally says who is responsible for the windows, so it’s worth checking before booking.
A 12-month guarantee comes with the work, just as it does everywhere we cover.
- Place
- Harlington (UB3, TW6, UB7)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quote
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
How the visit works
There isn’t much for you to do on the day. Point us to the joints and we’ll get on with it. The work itself takes a few hours for a few frames, or a day or more for a whole house, including the tidy-up. For a job in Harlington, parking and access are the things to plan: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- 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.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- Move anything stored near the joints
- Let us know if you’ve seen damp or leaks
Ask for a quote
Asking for a quote is easy: tell us what needs doing and where, and roughly how big it is. Photos by email help us understand the job.
Advice
What happens if it’s left?
Redecorating is a good moment to renew the mastic. A clean new bead makes new paint or render look finished. In London conversions, one flat’s bathroom is often above another flat’s ceiling, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble for homes in Harlington.
A few things move the cost up or down: the old material and how easily it comes out, whether mould needs treating, and whether we need extra access for height. Your quote takes all of that into account.
Why choose Mr Mastic in Harlington
- An ARBOMaster approved applicator
- Any old sealant cut out fully, not covered over
- Domestic, commercial and hotel work
- You choose the colour before work begins
Read what affects the cost or our reviews.
Keeping the joints in good condition
Good habits help new joints last longer. A few tips:
- Keep paint and stain on wooden frames in good order
- Look round the frames every year or so
- Air rooms to keep condensation down around windows
- Keep paint off silicone joints
A yearly look round the frames is enough. Small splits are simple to catch before they leak, and if anything looks wrong, just call 0345 464 0079 or email us.
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.
When to call us in Harlington
Sun, frost and rain wear sealant out. Sunlight dries the surface out, and over the years it loses its give, cracks and comes away.
Common reasons people contact us are:
- Hard, cracked sealant around windows
- Gaps left after new windows were fitted
- Gaps where the sill meets the wall
- Whistling draughts around closed windows
Harlington is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Before booking anyone
- How long to leave it before use
- What insurance they hold
- Is the old sealant removed completely?
- What preparation is included
Landlord and commercial work in Harlington
Housing providers, facilities teams and property managers book us too. Several sites can go on one quote, and we are fully insured.
Failed sealant is one of the commonest items on a check-out report. Several properties can go on one quote.
How the job changes by surface
Composite doors
Front doors take the weather head on, and the top and bottom corners tend to fail first. We pay most attention there.
Timber windows & doors
Where timber has rotted at the joint, it needs repairing first. We will point out any rot we find, as that is a job for a joiner.
Harlington questions
Is Harlington in your area for window mastic?
Yes, Harlington is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or send us an email and tell us what needs doing, and we will give you a clear price.
Is parking a problem for a job in Harlington?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Do you work on first-floor windows?
Yes, as long as they can be reached safely. Let us know about access when you ask for a quote so we can plan the job.
Can you do several jobs on one visit?
Yes, and it often makes sense. Doing several areas at once is generally more efficient.
How long should I leave it?
Many sealants skin over quickly but take longer to cure fully. We will tell you how long to leave the joint before we leave.
Where is Mr Mastic based?
We’re based in Crawley, and we cover South East England, London and all of Scotland.
Is it messy?
No. We protect the surfaces around the joints, and we clear up the old sealant and our materials before we leave.
What sealant do you use?
Each joint gets the product that suits it. Movement, water and weather all affect the choice.
Towns and villages near Harlington
Other services in Harlington
Harlington homes and the weather
London and the South East are among the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. Historic houses like Osterley House (about 3.6 miles east) are a reminder that the area around Harlington has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
For an older house near a landmark such as Church of St Peter and St Paul, the joint between an old wall and a newer frame is generally the first place rain gets in. For site and facilities teams at buildings such as William Byrd Primary Academy, its window and door frames need their mastic kept sound, just like a home’s.
Harlington is about 2 miles south-east of West Drayton, in Greater London. Our applicators cover window mastic for homes and businesses in Harlington. We cover 764 towns and villages across Greater London, from the larger towns to small villages. There’s also a page for London, about 15 miles away.
All of UB3, TW6 and UB7 is covered for window mastic, from the main roads to the quietest streets. Whether your property is on New Road, Bath Road and Manor Lane or anywhere close by, our applicators can take on the job. We also cover Sipson (1 mile north-west), Hatton (1 mile south-east), Cranford (1 mile south-east), Heathrow (1 mile south-west) and Harmondsworth (2 miles west). We also work in nearby towns such as London (15 miles east), City of Westminster (12 miles east), Marylebone (13 miles east), Kensington (10 miles east), St Pancras (14 miles east) and Hoxton (15 miles east).
Local landmarks in Harlington
We work in homes and buildings around The Red Lion pub, Harlington Community School and Lake Farm Country Park, among other places. Harlington’s nearest station is Heathrow Terminals 2 & 3 Rail station, about 1.2 miles south-west. Nearby you’ll also find Harlington (0.6 miles north-west) and Treaty Centre (3.4 miles east). The countryside around Harlington includes Staines Reservoirs and Crane Meadows.
What sealant work cannot fix
To be straight with you, some problems need a different trade:
- A frame that has rotted at the joint
- Misting between the panes of a double-glazed unit (that needs a new unit)
- Faulty window hardware
If in doubt, phone 0345 464 0079 or drop us an email and we’ll say what we think.
Joints and surfaces we work on
- Timber windows & doors
- Window sills
- Aluminium frames
- Composite doors
- Patio & French doors
- uPVC windows