Greater London · England
Sand Mastic in Cannon Hill
Specialist sand mastic for Cannon Hill: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Draughty sash windows at the surround
- Open joints round the window box
- Gaps round a timber door in stone or brick
Sand mastic in Cannon Hill
Fresh sand mastic forms a skin quite soon but full hardening takes longer. Traditionally, sand mastic is left unpainted, so ask us before you decorate. We work on period & listed homes, brick reveals and stone surrounds, and common reasons people get in touch are modern sealant on a period surround and weathered mastic on the most exposed windows.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. Over the years, the sealant around them shrinks, cracks and pulls away, which is when draughts and damp patches appear in homes in Cannon Hill.
Whatever the size of the job, you get the same one-year guarantee.
- Place
- Cannon Hill (SW20, SM4, KT3)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quotes
- A clear price before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Surface by surface
Sash and case windows
A sash window’s box frame sits in the masonry opening. Sand mastic seals the joint round it.
Stone surrounds
We take care not to mark the stone while raking out the old mastic.
Landlords, agents and businesses in Cannon Hill
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance that we can handle for you.
From a single let to a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a 12-month guarantee.
Aftercare tips
No joint lasts for ever, but care makes a real difference. Our tips:
- Plan mastic work ahead of painting
- Make sure water runs off the sill
- Ask the planning authority about consent for listed or conservation-area homes
- Go gently near the mastic when preparing windows
Keep paint scrapers and sanders off the mastic when redecorating. Hard scraping can loosen it.
Fine cracks show the mastic is starting to fail. Renewing it then is simpler than waiting until it falls out.
Honest limits
Before booking, it’s worth knowing the limits:
- Broken panes
- Crumbling stone or brickwork round the window
- Timber that has rotted
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think.
Joints and surfaces we work on
- Timber door frames
- Brick reveals
- Stone surrounds
- Sash and case windows
- Tenement windows
- Period & listed homes
Should I try it myself first?
If you’re set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
If you’ve already had a go yourself, that’s fine. We cut it out and start again.
What sand mastic looks like in Cannon Hill
Historic houses like Southside House (about 1.2 miles north-west) are a reminder that the area around Cannon Hill has older buildings as well as new. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic. In London conversions and blocks, the lease decides who is responsible for the frames, so check that before you book.
Letting a property close to South Merton station? Then older sash windows in a rental need their mastic kept sound to keep the weather out. Cannon Hill is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. If you look after a building such as Hillcross Primary School, its window and door frames need their mastic kept sound, just like a home’s.
Cannon Hill is about 1 mile north-west of Morden, in Greater London. Homes, rented property, offices and hotels in Cannon Hill can book us for sand mastic, old or new, large or small. The work is guaranteed for a year. Our area takes in 764 places across Greater London, large and small. We also work in London, around 9 miles away.
Every address in SW20, SM4 and KT3 is covered for sand mastic, from the main roads to the quietest streets. Whether your property is on Aylward Road, Camborne Road and Botsford Road or anywhere close by, our applicators can take on the job. We also cover the places around Cannon Hill: Bushey Mead (1 mile north-west), Raynes Park (1 mile west), Wimbledon Chase (1 mile north), West Barnes (1 mile west) and Merton Park (1 mile north-east). Larger places within reach include London (9 miles north-east), City of Westminster (8 miles north), Marylebone (9 miles north), Kensington (7 miles north), St Pancras (10 miles north-east) and Shoreditch (11 miles north-east).
Near you in Cannon Hill
Around Cannon Hill, our work takes us to homes and buildings near The Edward Rayne pub, Cannon Hill Common and Harris Academy Wimbledon and the streets around them. Cannon Hill’s nearest station is South Merton station, about 0.5 miles north-east. Well-known places in the area include St. Anthony's Hospital (1.5 miles south) and Wimbledon Museum (1.6 miles north). For a walk, there’s Cherry Wood and Henman Hill.
Also near Cannon Hill
More services for Cannon Hill
FAQs for Cannon Hill
Can parking be tricky for a visit in Cannon Hill?
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.
I let a flat near South Merton station. Can you help?
Yes, rental work is part of what we do. You can ring 0345 464 0079 or drop us an email with the address and a few details, and we will give you a fixed price before any work starts.
Is consent needed for window work on a listed home?
It’s best to ask your local planning authority first. Like-for-like sand mastic is often the preferred finish, but they decide.
Is it messy?
No. We protect the surfaces around the joints, and we clear up the old sealant and our materials before we leave.
What sealant do you use?
It depends on the joint: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. We use products from Arbo and Everbuild.
Can I paint the new mastic?
Traditional guidance is not to paint over sand mastic. Ask us before you decorate around it and we’ll talk you through it.
Are you ARBOMaster approved?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
Is it possible to take out silicone and use sand mastic instead?
Often, yes. Once the silicone is out and the joint prepared, sand mastic is applied by hand.
Why it’s worth doing now in Cannon Hill
Cement-based fillers and modern sealants don’t always suit a period surround. Sand mastic matches what was there and that can be important for listed homes. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and by the time it shows on a wall or ceiling in Cannon Hill, the repair is bigger than the sealant job would have been.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
What you get with us
- 12-month guarantee on every job
- Fully insured
- Approved under the ARBOMaster scheme
- Anti-fungal silicone where joints get wet
How it works
Our applicators work methodically: protection first, then preparation, sealing and a tidy-up. Typically it takes a few hours for a single window, longer for several, and the area is left clean. 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.
- Each surround is checked first.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic is not too thick.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
Before we arrive
- Tell us about access, such as stairs, a lift or high-level joints
- Mention any parking rules near the property
- For indoor joints, keep the area dry beforehand if you can
Ask for a quote
For a quote, phone 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. You will have a clear quote before work begins.