Greater London · England
Osterley Sand Mastic
Our applicators work in Osterley on traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old sealant removed completely, joints prepared properly.
- Draughty sash windows at the surround
- Window mastic to renew ahead of painting
- Old sand mastic that has cracked, crumbled or fallen out
Sand mastic in Osterley
Across Osterley, we renew sand mastic around sash and case windows. Each joint is raked out, prepared and pointed by hand, finished to suit the masonry. We work on sash and case windows, stone surrounds and timber door frames, and people most often call us about silicone on a period window that looks wrong and window mastic to renew ahead of painting.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease usually says who is responsible for the windows, so it’s worth checking before booking, and access in Osterley is something to talk through when you book.
Your job is guaranteed for a year, as with all our work.
- Location
- Osterley (TW7, TW3, TW5)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quotes
- A clear price before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
What sand mastic looks like in Osterley
With historic houses such as Osterley House (about 0.3 miles north) nearby, there’s older building stock in the area around Osterley as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window. In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
If you live in an older home near St Mary's Church, the joint between an old wall and a newer frame is generally the first place rain gets in. Osterley is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. Schools such as Isleworth and Syon School for Boys are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
Osterley is about 1 mile north of Hounslow, in Greater London. Every kind of property in Osterley can book us for sand mastic, old or new, large or small. The work is guaranteed for a year. Osterley is one of 764 towns and villages in Greater London we cover. For nearby work, see our London page.
We cover every part of TW7, TW3 and TW5 for sand mastic and the streets around it. That includes homes and businesses on Jersey Road, Church Road and Gresham Road and the roads around them. Neighbouring places we cover for sand mastic 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).
What’s near Osterley
In Osterley, that means homes and buildings near The Plough Public House, Spring Grove Primary School and Inwood Park, among other places. Osterley’s nearest station is Isleworth station, roughly 0.9 miles south-east. Nearby you will also find Museum of Army Music (2.1 miles south) and West Middlesex University Hospital (1.3 miles south-east). For a walk, there’s Castlebar Hill and Garden Lake.
Towns and villages near Osterley
More services for Osterley
What we do, step by step
The work is kept neat and contained to the joints we are treating, so you can get on with your day. Expect the work to take a few hours for a single window, longer for several. In Osterley, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- We look at the surrounds with you and agree the joints to renew.
- Old mastic and any loose material are raked out.
- We pack any deep voids first.
- We apply the mastic by hand and shape it.
- We dress the finish so it sits neatly against the masonry.
Before we arrive
- Let us know about earlier repairs to the joints
- On commercial sites, let us know about site rules
- Mention any tricky access
Ask for a quote
We quote each job on its own, so start by telling us what you need. Simply call 0345 464 0079 or drop us an email and describe the job, and photos are welcome.
Advice
Looking after it afterwards
Good habits help new joints last longer. Our tips:
- Keep modern sealant off the mastic
- Sort the mastic before the decorators arrive
- Avoid heavy scraping on the mastic joint
- Find out about consent before window work on a listed home
When preparing windows for paint, take care around the mastic. Hard scraping can loosen it.
Good mastic helps keep the frame dry. Once it fails, water can sit against the timber and timber that stays wet can rot.
How the job changes by surface
Sash and case windows
The mastic round a sash window is on show, so a neat, even finish matters.
Timber door frames
Doors face weather and wear and the mastic can crack early. It’s renewed by hand.
What happens if it’s left?
Before painting the windows, it pays to renew the mastic. Paint over cracked mastic will not stop the gaps and traditional guidance is to leave the new mastic unpainted. In a flat in Osterley, 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.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, any mould to treat, and whether we need extra access for height. We take all of that into account in your quote.
What you get with us
- Full insurance on every job
- Old sealant always removed completely
- Domestic, commercial and hotel work
- We leave the area clean and tidy
See how sealant jobs are priced and our reviews.
What affects the cost of sand mastic
Call for a quick quote. The main things that affect it are:
- How many areas need sealing
- Access and height
- The old material and how stubborn it is
- The product the joint needs
Instead of a standard rate, we price the job in front of us: how many joints, what’s in them now and how we reach them. You’ll know the price before we begin.
What to tell us for a quote
When you call or email, these details help:
- A few pictures by email, if you can
- The rough size of the job
- Any previous sealing or DIY work
- Whether it’s a home or a business
Need a quote? Please call 0345 464 0079 or email us with a few details. We will explain what we’d do and send you a clear quote before any work starts.
FAQs for Osterley
Is parking a problem for a job in Osterley?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. The visit is then planned around what’s available.
Do you work for landlords with property near Isleworth station?
Yes. We work for letting agents and landlords as well as householders, and several properties can be quoted together. Just phone 0345 464 0079 or send us an email with the address and what needs doing, and we will send you a clear quote.
Should I check with the council before work on a listed or conservation-area home?
Your local planning authority is the one to ask. They decide whether consent is needed.
Are you fully insured?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
Do I need to be at home?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
Is sand mastic better than silicone for my windows?
Sand mastic usually suits period timber windows best. Modern frames normally suit a flexible sealant.
Do you remove the old sealant?
Yes. We cut out all the old sealant and clean the joint.
Can you work on commercial sites?
Yes. We have worked for hotels, offices and other businesses.
Landlord and commercial work in Osterley
In hotels, rooms out of use cost money, so we plan the work room by room. We’ve worked in hotels as well as homes and businesses.
Letting agents often deal with us directly. Tell us the address, the job and how access works and we will give you a quote.
When something else is needed
Sealant isn’t the answer to every problem, and we’d rather say so up front. It will not solve:
- Broken panes
- Sashes that need overhauling
- Masonry that needs repairing
Not sure which it is? You can phone 0345 464 0079 or email us and we’ll tell you honestly before booking.
Where we work in Osterley
- Stone surrounds
- Timber door frames
- Sash and case windows
- Tenement windows
- Brick reveals
- Period & listed homes