Greater London · England
Sand mastic for sash & case windows in Harlington, Greater London
Sand mastic for Harlington, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Cement or filler used on old window joints that has cracked
- Mastic round period door frames that has failed
- Mastic dropping out of the joint
How to look after the new joints
Joint life depends on how it’s used and looked after. We suggest:
- Sort the mastic before the decorators arrive
- Look over the window mastic once a year
- Make sure water runs off the sill
- Check with your local planning authority if your home is listed
Keep gutters and sills clear so water runs away from the surround. Constant wetting wears the mastic faster.
Gaps round a sash box let in draughts and rain. Left, the gap tends to get bigger.
Sand mastic in Harlington
We work across Harlington renewing sand mastic on sash windows and doors. Each joint is raked out, prepared and pointed by hand for a neat, traditional finish. If you have patchy fillers round a sash window and old sand mastic that has cracked, crumbled or fallen out, we can put it right, whatever the surface.
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 Harlington is something to talk through when you book.
There’s a 12-month guarantee on every job, large or small.
- Location
- Harlington (UB3, TW6, UB7)
- Wider area
- Greater London
- Cover
- 12 months on all our work
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
When it is not the sealant
Some problems need a builder, plumber or other trade rather than us:
- Whether work needs listed building consent
- Crumbling stone or brickwork round the window
- Broken panes
Not sure which it is? You can phone 0345 464 0079 or email us and we will tell you honestly before you book.
Joints and surfaces we work on
- Tenement windows
- Sash and case windows
- Stone surrounds
- Timber door frames
- Brick reveals
- Period & listed homes
How we quote for sand mastic
Some jobs are bigger than they look, and some smaller. What affects the quote:
- Which sealant suits the joint
- The number of rooms or windows
- The number and length of the joints
- Any mould that needs treating
Combining jobs into one visit normally makes better use of the time than several visits, so tell us about everything that needs sealing. You will get one clear quote for the whole job.
Helping us quote
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- Photos by email, if that’s easy
- Where the property is
- Roughly how big the job is
- If it’s domestic, commercial or a hotel
For a quick quote, get us on the phone, or send an email if you’d rather. Describe what needs sealing and we’ll explain what’s involved before giving you a price.
How the visit works
Every visit runs the same way: we look at the joints together, protect the area around them, carry out the job and tidy away. Most jobs take a few hours for a single window, longer for several. For a job in Harlington, parking and access are the things to plan: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- Each surround is checked first.
- The joint is raked out and cleaned.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Clear items away from the joints we are working on
- Mention any parking rules near the property
- On commercial sites, let us know about site rules
Get a quote
Every job is quoted individually, so the first step is telling us about yours. Simply phone 0345 464 0079 or send us an email and describe the job and send photos if you have them.
Advice
Why deal with it now?
Draughts round a sash window are not always the sashes. Gaps between the frame and the wall can be just as bad and new mastic seals them. In a London flat, a failed joint rarely stays your problem alone: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
No two jobs are quite the same, so we quote each one individually. Size, access and the product the joint needs all play a part, and we will explain the quote if you ask.
Why choose Mr Mastic in Harlington
- Over 20 years’ experience
- Any old sealant cut out fully, not covered over
- Tidy, careful work
- Full insurance on every job
Take a look at our cost guide and what customers say.
DIY sealant or a professional job?
If you’ve already had a go yourself, that’s fine. We remove it and do the joint properly, so just mention it when you contact us.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and doesn’t move well, and getting the depth right matters as much as the look.
What sand mastic looks like in Harlington
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. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
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. As a London address, Harlington can be tricky for parking: let us know about parking bays, permits or a driveway. If you let a flat or house near Heathrow Terminals 2 & 3 Rail station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
Harlington is about 2 miles south-east of West Drayton, in Greater London. Anywhere in UB3, we can carry out sand mastic at your property. Across Greater London, we cover 764 places, Harlington among them. London is on our list too, around 15 miles away.
Jobs for sand mastic in UB3, TW6 and UB7 works the same way as everywhere else we cover. Sand mastic is available to properties on New Road, Bath Road and Manor Lane. Nearby, we also carry out sand mastic in 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
In Harlington, that means homes and buildings near The Red Lion pub, Harlington Community School and Lake Farm Country Park. For rail, the closest station is Heathrow Terminals 2 & 3 Rail station, roughly 1.2 miles south-west. Well-known places in the area include Harlington (0.6 miles north-west) and Treaty Centre (3.4 miles east). Open spaces near Harlington include Staines Reservoirs and Crane Meadows.
Towns and villages near Harlington
Other services in Harlington
Work for landlords, hotels and businesses
Failed sealant is one of the commonest items on a check-out report, and it’s quick to put right between tenancies. Several properties can go on one quote.
Letting agents and landlords in Harlington can book us as well as homeowners. Sealant work between tenants keeps a property looking cared for.
Harlington questions
Is parking an issue for sand mastic in Harlington?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
I let a flat near Heathrow Terminals 2 & 3 Rail station. Can you help?
Yes, we work for landlords and agents. You can ring 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before work begins.
What does sand mastic cost?
Size, access and the old material all affect the cost. Call for a quick quote.
Do you work in Harlington?
Yes, we do. Harlington is part of the area we cover, and the service is the same as everywhere else.
Do you work for hotels and businesses?
Yes. Hotels, offices and other businesses use us and we’re fully insured.
How long does sand mastic take to harden?
It takes a while. The skin forms first, and the full set comes later, and we’ll tell you what to expect.
Will the old sealant be removed?
Yes. We cut out all the old sealant and clean the joint before applying anything new.
Is it worth trying it myself?
Some simple jobs can be done by a careful DIYer. Most DIY failures come from sealing over old material, wet joints or too much sealant.