Greater London · England
Window Mastic in Isleworth
We cover Isleworth for mastic around window and door frames, sills and patio doors. Old material cut out, joints cleaned and sealed neatly.
- Leaking joints at the ends of sills
- Sealant in the wrong colour for the frame
- Water coming in at the bottom corners of a door
Window mastic in Isleworth
If you can feel air around a shut window, the gap is often at the frame. Resealing that joint can make a room feel noticeably less draughty. If the draught is through the window seals instead, we’ll tell you. If you are dealing with leaking joints at the ends of sills and whistling draughts around closed windows, we can put it right.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out, in Isleworth as anywhere.
Whatever the size of the job, you get the same 12-month guarantee.
- Location
- Isleworth (TW7, TW1, TW3)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before work begins
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Common questions in Isleworth
Do you cover Isleworth for window mastic?
Yes, Isleworth is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or drop us an email and let us know what needs doing, and we will send you a clear quote.
I let a flat near Isleworth station. Can you help?
Yes, we work for landlords and agents. Just call 0345 464 0079 or email us and tell us about the property, and we’ll send you a clear quote.
Do you work for hotels and businesses?
Yes. We have worked for hotels, offices and other businesses and we’re fully insured.
Do you remove the old sealant?
Yes, always, and completely. New silicone doesn’t stick to old silicone, so the joint is cleaned back first.
Will it make a mess?
Not at all. The area is protected while we work and cleaned up afterwards.
What do you put in the joint?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
Are you fully insured?
Yes. We’re fully insured, with over 20 years’ experience in sealant work.
Will new mastic stop draughts?
If the draught is coming in around the frame, yes. If it’s coming through the window seals, we will tell you.
What the job involves on each 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.
Window sills
Where a sill meets brick or render, the ends often crack first. A tight seal at each end keeps rain out of the wall.
For landlords and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we will quote.
Landlords and letting agents in Isleworth can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
How the visit works
Once we’re on site, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. Most jobs then take most of a day for a typical house, less for a few frames. In Isleworth, flats, stairs and shared entrances are part of the routine. If the building has a concierge, managing agent or access rules, tell us when you book.
- First, we confirm safe access to each frame.
- All the failed sealant is cut away.
- The surfaces are cleaned and left dry, and primed where the sealant calls for it.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
Before we arrive
- On commercial sites, let us know about site rules
- Mention any parking rules near the property
- Mention any tricky access
How to get a quote
There’s no standard price list, as no two jobs are quite the same. Instead, we give you a clear price for your job. To get started, phone 0345 464 0079 or drop us an email.
Read more
Also near Isleworth
Also in Isleworth
When to call us in Isleworth
Sills take more water than any other part of a window, so the sill ends and the joint below the frame are common leak points. Failed sealant there lets rain into the wall or behind the frame.
The most common problems we see are:
- Damp patches on the reveal after heavy rain
- Gaps where the sill meets the wall
- Gaps left after new windows were fitted
- Cold air getting in at the frame edge
For landlords with property near Isleworth station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
What to look for in a quote
- What happens if they find a problem under the old sealant
- How the joint is cleaned and prepared
- Whether you can choose the colour
- Is the old sealant removed completely?
What window mastic looks like in Isleworth
With historic houses such as Syon House (about 0.9 miles north-east) nearby, there’s older building stock in the area around Isleworth as well as newer homes. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Homes close to Church of All Saints include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. Isleworth is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
Isleworth is about 2 miles north of Twickenham, in Greater London. Jobs in Isleworth 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 Isleworth is one of them. There’s also a page for London, about 10 miles away.
We work across the TW7, TW1 and TW3 postcode area for window mastic and the streets around it. If you need window mastic at a property on Upper Square, London Road and Shire Horse Way or anywhere close by, we can help. Neighbouring places we cover for window mastic include Woodlands (1 mile west), St Margarets (1 mile south-east), Ivybridge (1 mile south-west), Spring Grove (1 mile north-west) and Hounslow (1 mile west). We also work in nearby towns such as London (10 miles east), City of Westminster (8 miles east), Marylebone (9 miles north-east), Kensington (6 miles east), St Pancras (10 miles north-east) and Shoreditch (12 miles east).
Landmarks near Isleworth
Locally, jobs take us to homes and businesses close to The George Inn, Kneller Hall Junior School and Gumley House RC Convent School and the streets around them. There’s a railway station in Isleworth itself: Isleworth station. Other landmarks nearby include West Middlesex University Hospital (within half a mile north-east) and Museum of Army Music (1.4 miles south-west). For a walk, there’s Richmond Hill and Kew Gardens Lake.
Why act early in Isleworth
If you’re painting or rendering, reseal at the same time. Fresh joints finish the job neatly. Damp from a failed joint spreads quietly in older London brickwork and timber, and once it shows in Isleworth, the repair is bigger than a sealant job.
We don’t show prices on the website, because each job is priced on what it involves. For a quick quote, please phone 0345 464 0079 or email us and we will talk you through it.
Why book with us
- We never seal over old sealant
- Rated 4.9 stars on Google
- A sealant colour to suit the surroundings
- Neat joints and a tidy finish
See our cost guide and our reviews.
How to look after the new joints
How long the joints last depends on use and care. We suggest:
- Wash the frames with mild soapy water
- Walk round the house once a year and look at the joints
- Keep solvents and bleach off the sealant
- Avoid blasting the frames with a pressure washer
Most silicone sealants won’t take paint, so if you’re planning to paint the frames or walls, tell us beforehand. There are paintable sealants for joints that need it.
A small gap around a frame only grows. As old mastic keeps shrinking, the gap widens, and a cold room gets colder. A new joint closes it up.
When something else is needed
We will always be straight with you, so here’s what new sealant will not do:
- A door that needs adjusting, rehanging or new seals
- Misting between the panes of a double-glazed unit (that needs a new unit)
- Faulty window hardware
If in doubt, call 0345 464 0079 or drop us an email and we will say what we think before booking.
Where we work in Isleworth
- Window sills
- uPVC windows
- Patio & French doors
- Composite doors
- Timber windows & doors
- Aluminium frames