Greater London · England
Osterley Window Mastic
Window mastic for Osterley and the surrounding area: careful preparation, the right product and tidy work. Ask us for a quick quote.
- White mastic on grey or black frames
- Mastic that has split away from the wall
- Gaps left after new windows were fitted
For landlords and businesses
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
For anyone letting property in or around Osterley, several properties can go on one quote. Send us the addresses and the work at each, and pictures by email help.
Window mastic for homes and businesses in Osterley
Over two decades of sealing frames has taught us which products suit which walls. We are fully insured ARBOMaster approved applicators, and we give a 12-month guarantee on the work. We work on aluminium frames, window sills and patio & French doors, and the jobs we see most are cold air getting in at the frame edge and cracked or shrunken mastic around the frame.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first, and access in Osterley is something to talk through when you book.
The work is covered for a year after we finish. If there’s a problem with it, please phone 0345 464 0079 or drop us an email.
- Place
- Osterley (TW7, TW3, TW5)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quote
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Keeping the joints in good condition
Aftercare is simple, and it makes a real difference:
- Do not paint over the silicone
- Keep timber frames painted
- Keep solvents and bleach off the sealant
- Check the mastic once a year
Keep sill grooves and drainage slots clear, so rain drains out rather than building up at the sealant.
Signs to watch for: cracks in the mastic, gaps you can see light through, damp on the reveal or mould around the inside of the frame. Any of these is worth a call.
What affects the quote in Osterley
Some jobs are bigger than they look, and some smaller. The main factors:
- Access and height
- Working hours on commercial sites
- How much old sealant there is and how hard it is to remove
- How many areas need sealing
The cost reflects the work involved, not a rough estimate. That’s why we ask a few questions first and agree the price before starting.
Asking for a quote
Photos by email are helpful but not essential. Please mention:
- If it’s domestic, commercial or a hotel
- How we’d reach the joints
- Where the property is
- A few pictures by email, if you can
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is, and we will talk you through what we’d do. Whenever you are ready, call 0345 464 0079 or send us an email.
Towns and villages near Osterley
Also in Osterley
When to call us in Osterley
Plenty of failed mastic was poorly applied in the first place. Mastic laid onto dusty, damp or crumbling surfaces didn’t grip properly, and it lets go sooner than it should.
These are the problems we are asked about most:
- Hard, cracked sealant around windows
- Cracked internal joints between frame and plaster
- Sealant in the wrong colour for the frame
- Mastic that’s falling out in pieces
Schools such as Isleworth and Syon School for Boys are buildings too, and the mastic around its windows and doors needs looking after like any other building’s.
What to look for in a quote
- What the quote includes, VAT included or not
- The length of the guarantee
- Who turns up on the day
- Whether all the old sealant comes out first
What we cannot put right
We will not take on work that will not last, so these are the limits:
- A sash or casement that won’t close properly
- A door that needs adjusting, rehanging or new seals
- Damp coming through the wall itself rather than the frame joint
Not sure which it is? You can phone 0345 464 0079 or send us an email and we will tell you honestly before you book.
Where we work in Osterley
- Patio & French doors
- Window sills
- Timber windows & doors
- Composite doors
- Aluminium frames
- uPVC windows
What the job involves on each surface
Window sills
Every drop off the glass ends up on the sill, so the sill ends and the joint under the frame are vital. Each is cleaned out and resealed.
Patio & French doors
Not every patio door leak is a mastic problem: blocked drain slots, worn brush seals and threshold details can let water in too. We look for the cause first.
Window mastic in Osterley: local notes
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. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.
Osterley is in London, so parking needs planning: let us know about parking bays, permits or a driveway. For landlords with property near Isleworth station, renewing tired window mastic between tenants heads off draught and damp complaints.
Osterley is about 1 mile north of Hounslow, in Greater London. For window mastic in and around Osterley, it’s easy to get a quote: please ring 0345 464 0079 or drop us an email. We are based in Crawley and cover Greater London, Osterley included. We cover 764 towns and villages across Greater London, large and small. You can also see our page for London, roughly 11 miles from Osterley.
Work in TW7, TW3 and TW5 is quoted and booked the same way as anywhere else. Local streets include Jersey Road, Church Road and Gresham Road. Other places close to Osterley include Spring Grove (1 mile south-east), Lampton (1 mile south-west), Norwood Green (1 mile north-west), Gillette Corner (1 mile east) and Woodlands (1 mile south). We also work in nearby towns such as London (11 miles east), City of Westminster (9 miles east), Marylebone (9 miles east), Kensington (6 miles east), St Pancras (10 miles east) and Shoreditch (12 miles east).
Around Osterley
In Osterley, that means homes and buildings near The Plough Public House, Spring Grove Primary School and Inwood Park and the streets around them. The closest station to Osterley is Isleworth station, about 0.9 miles south-east of the centre. Other landmarks nearby include Museum of Army Music (2.1 miles south) and West Middlesex University Hospital (1.3 miles south-east). Not far away are Castlebar Hill and Garden Lake.
Your questions about window mastic in Osterley
Is parking an issue for window mastic in Osterley?
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.
I let a flat near Isleworth station. Can you help?
Yes. We work for letting agents and landlords as well as homeowners, and several properties can be quoted together. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear quote.
Is the new sealant paintable?
That depends on the product. Some hybrid sealants can be painted; silicone can’t. Tell us if you are decorating and we will choose accordingly.
How long should I leave it?
That depends on the sealant used, so follow the cure time we give you.
How do I get a quote for window mastic in Osterley?
The cost depends on the size of the job, access and how much old sealant has to come out. Call for a quick quote.
Do you take out the old sealant first?
Yes. Sealing over old sealant is the main reason resealing fails early, so we never do it.
Will you leave a mess?
Not at all. The area is protected while we work and cleaned up afterwards.
Is it worth trying it myself?
It depends on the job. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional, while a short indoor joint may be within reach.
The process
We work through the job in order: protect, prepare, seal, tidy. Typically it takes most of a day for a typical house, less for a few frames and we leave things clean and tidy. 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.
- We check how each frame can be reached safely.
- Old, cracked mastic is removed completely, along with any loose debris.
- The surfaces are cleaned and left dry.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
Getting ready for the visit
- Move anything stored near the joints
- Keep pets and children clear of the area while we work
- Mention any sign-in or site rules at work premises
Get a quote
Need a quote? Please phone 0345 464 0079 or send us an email with a few details. We’ll explain what we’d do and send you a clear quote before we start.