Greater London · England
Chelsea Harbour Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in Chelsea Harbour, with a 12-month guarantee on every job. Ask us for a quote.
- Draughty sash windows at the surround
- Gaps where the frame meets the masonry
- Gaps round a timber door in stone or brick
DIY versus a professional finish
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
If you’ve already had a go yourself, that is fine. We cut it out and start again.
Sand mastic for homes and businesses in Chelsea Harbour
Our applicators renew the sand mastic around sash and case windows and doors set in stone or brick. Out comes the old, loose mastic, and new mastic is applied and shaped by hand. We work on tenement windows, brick reveals and stone surrounds, and the jobs we see most are gaps where the frame meets the masonry and modern sealant on a period surround.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. The mastic around them dries out and cracks with age, which is when draughts and damp patches appear in homes in Chelsea Harbour.
Your job is guaranteed for a year, as with all our work.
- Location
- Chelsea Harbour (SW6, SW11, SW10)
- Region
- Greater London
- Cover
- A year, on every job
- Price
- A clear price before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Also near Chelsea Harbour
What else we do in Chelsea Harbour
What happens on the day
We keep the work tidy and contained to the area we’re working on, so you can get on with your day. The job generally takes a few hours for a single window, longer for several. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Chelsea Harbour. It helps if you can point us to a visitor permit or a bay close to the door.
- We start by checking each surround and agreeing the joints to renew.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- We dress the surface so it sits neatly against the masonry.
Getting ready for the visit
- Mention any tricky access
- Tell us about any previous sealing or DIY attempts
- Let us know about parking restrictions
How to get a quote
Need a quote? Please call 0345 464 0079 or drop us an email and tell us about the job. You will know what we plan to do, and what it will cost, before any work begins.
Related advice
Why it’s worth doing now in Chelsea Harbour
Replacing sash windows is a big decision for a period home, and in listed buildings it may need consent. If the frames are sound, renewing the mastic deals with gaps and draughts at the surround. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Chelsea Harbour, the repair is bigger than a sealant job.
No two jobs are quite the same, so each one gets its own quote. Size, access and the product the joint needs all play a part, and we will explain the quote if you ask.
Why us?
- 20+ years of sealant experience
- 4.9 on Google from 180+ five-star reviews
- Sanitary silicone with an anti-fungal additive in wet areas
- We never seal over old sealant
Read what affects the cost and our reviews.
FAQs for Chelsea Harbour
Do you work for landlords with property near Imperial Wharf station?
Yes, we work for letting agents and landlords. Just ring 0345 464 0079 or email us and tell us about the property, and we’ll give you a clear price.
Is Chelsea Harbour in your area for sand mastic?
Yes. Our work covers London and the South East, and Chelsea Harbour is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job, and we’ll give you a clear quote.
Are you insured?
Yes. Full insurance covers our work.
Should I check with the council before work on a listed or conservation-area home?
Yes, it’s worth checking. Your local planning authority can say if consent is needed for work on a listed home or in a conservation area.
Is it possible to take out silicone and use sand mastic instead?
Yes, we do this often. All the old silicone is removed first so the mastic can sit properly.
Is it worth trying it myself?
Sometimes. The key is preparation: remove all the old material and work on a clean, dry joint. We can always put it right if it fails.
Where are you based?
Our base is Crawley. Our area covers South East England, London and Scotland.
Can I paint the new mastic?
Sand mastic is normally left unpainted, which is what traditional guidance recommends. Ask us before decorating.
Keeping the joints in good condition
Looking after new joints is easy:
- Inspect the joints round the windows every year or so
- Avoid heavy scraping on the mastic joint
- Have rotten timber repaired before new mastic goes in
- Find out about consent before window work on a listed home
Look at the mastic when you look over the windows. Small cracks are easier to deal with early.
It’s best to renew mastic before painting the windows. Painting over failed mastic hides the problem for a while.
Frames and glazing around Chelsea Harbour
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 a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
Chelsea Harbour is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. Letting a property close to Imperial Wharf station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about. For an older house near a landmark such as St Mary's Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Chelsea Harbour is about 2 miles south-east of Kensington, in Greater London. Across the SW6 area, we can carry out sand mastic at your property. 764 places in Greater London are on our list, from the larger towns to small villages.
Postcode districts we cover here for sand mastic: SW6, SW11 and SW10. We cover properties on Ann Lane, York Road and Lots Road. Close by, we work in Sands End (1 mile south), Walham Green (1 mile north-west), World's End (1 mile north), Little Chelsea (1 mile north) and Parsons Green (1 mile west). We also work in nearby towns such as London (4 miles north-east), City of Westminster (3 miles north-east), Marylebone (3 miles north-east), St Pancras (4 miles north-east), Shoreditch (6 miles north-east) and Walthamstow (10 miles north-east).
Around Chelsea Harbour
Typical jobs here are in homes near Heatherley School of Fine Art, Lots Road pub and Imperial Park, among other places. Other local landmarks include Langford Primary School (within half a mile south-west) and Natural History Museum Library and Archives (1.5 miles north). Chelsea Harbour has its own railway station: Imperial Wharf station. Nearby you will also find Baynard's Castle (4.3 miles north-east) and Chelsea Stadium Tour And Museum (0.6 miles north-west). Green spaces nearby include WWT London Wetland Centre and Battersea Park Lake.
When it is not the sealant
We’d rather tell you now than do work that will not last, so here’s what sealant cannot put right:
- Cracked or broken glass
- Timber that has rotted
- Crumbling stone or brickwork round the window
If in doubt, phone 0345 464 0079 or drop us an email and we’ll say what we think before booking.
What we seal
- Tenement windows
- Stone surrounds
- Sash and case windows
- Brick reveals
- Period & listed homes
- Timber door frames
How the job changes by surface
Stone surrounds
Old stone surrounds are often uneven, so the joint varies in width. We shape it by hand to follow the stone.
Tenement and terrace windows
Upper-floor windows need access planning. Tell us the height and we’ll confirm what’s needed.
How we quote for sand mastic
For a quick quote, just ask. What matters most is:
- The product the joint needs
- Whether the work is at height
- Any mould that needs treating
- How many rooms, windows or areas are involved
The cost reflects the work involved, not a rough estimate. That is why we ask about the job first.
Asking for a quote
To help us quote quickly, please include:
- Pictures of the joints, sent by email
- The type of property
- How we’d reach the joints
- The address or postcode of the job
For a quick quote, get us on the phone, or email us if that is easier. Tell us about the joints that need doing and we will talk you through the work.