Greater London · England
Sand mastic for sash & case windows in Lessness Heath, Greater London
Sand mastic in Lessness Heath from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Wind and rain getting in round a sash window
- Modern sealant on a period surround
- Mastic round period door frames that has failed
Sand mastic in Lessness Heath
Sand mastic is the traditional way to point the gap between a timber window frame and the stone or brick around it. It’s made from sand and a linseed-oil-based binder, applied by hand. On older homes, it suits the building far better than silicone. If you have draughts and rain around sash boxes and a silicone bead on a sash window that spoils the look, we can help, whatever the surface.
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, letting in draughts and water.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Where
- Lessness Heath (DA17, DA8, DA7)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quote
- A clear price before we start
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Can I do it myself?
The biggest DIY mistake is sealing over old sealant. New silicone will not bond to old, so it peels away and traps moisture behind it. All the old material has to come out first.
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Towns and villages near Lessness Heath
More services for Lessness Heath
What happens on the day
We work through the job in order: protection first, then preparation, sealing and a tidy-up. Typically it takes anything from a few hours to a full day, depending on how many windows, and the area is left clean. In Lessness Heath, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- We check each window surround and the condition of the joint.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
Getting ready for the visit
- Clear items away from the joints we are working on
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us if parking is tricky
How to get a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will explain how we’d tackle it. When it suits you, ring 0345 464 0079 or drop us an email.
Advice
What sealant work can’t fix
We won’t take on work that won’t last, so here’s what sealant can’t put right:
- Rotten sashes, sills or window boxes (a joiner’s job)
- Sash cords, weights and draught-proofing of the sashes
- Damaged stone surrounds
If you’re not sure, just call 0345 464 0079 or email us and we will give you a straight answer.
Surfaces we seal
- Brick reveals
- Period & listed homes
- Timber door frames
- Stone surrounds
- Sash and case windows
- Tenement windows
What affects the cost of sand mastic
You’ll get a clear quote before work begins. It takes into account:
- How easy the joints are to reach
- The old material and how stubborn it is
- Whether there’s mould to deal with
- The product the joint needs
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, plus any working-time requirements on site. Call for a quick quote and we will go through it with you.
What to tell us for a quote
Before you ask for a quote, have a think about:
- Photos by email, if that is easy
- Whether it has been sealed before
- What the problem is, such as mould, gaps, leaks or cracking
- Access, such as stairs, a lift or height
We do not publish a price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To get started, ring 0345 464 0079 or drop us an email.
How to look after the new joints
A little care helps the new joints last. We recommend:
- Keep modern sealant off the mastic
- Take care around the mastic when scraping paint
- Ask us before painting near the mastic
- Clear gutters so water doesn’t pour onto the windows
Make sure water drains away from the window surround. Water sitting against the mastic shortens its life.
Sound mastic protects the frame. Once it fails, water can sit against the timber and timber that stays wet can rot.
Landlords, agents and businesses in Lessness Heath
Mouldy or split sealant often shows up at the end of a tenancy. Several properties can go on one quote.
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
Your questions about sand mastic in Lessness Heath
Do you work for landlords with property near Belvedere station?
Yes. We work for letting agents and landlords as well as homeowners, and several properties can go on one quote. You can call 0345 464 0079 or send us an email with the details for a clear quote.
Can parking be tricky for a visit in Lessness Heath?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
Do you do commercial work?
Yes, regularly. Larger jobs can be planned room by room or area by area to suit the site.
Which products do you use?
Quality sealants from brands including Arbo and Everbuild, picked for each joint. We explain the product when we quote.
Are you fully insured?
Yes. We’re fully insured.
Should I try DIY first?
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.
Is the work guaranteed?
Every job comes with our 12-month guarantee, and we’re fully insured.
Do you take out the old sealant first?
Yes, every time. New sealant will not bond properly to old, so any old material comes out before anything new goes in.
What we are called out for in Lessness Heath
Scraping and sanding before painting can loosen old mastic. Many people find it crumbling when they prepare the windows.
Common reasons people contact us are:
- Mastic dropping out of the joint
- Weathered mastic on the most exposed windows
- Gaps where the frame meets the masonry
- Draughts and rain around sash boxes
For an older house near a landmark such as Parish Church of All Saints, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Before booking anyone
- When the joint can take water or movement
- Who does the work, and how experienced they are
- What preparation is included
- Whether all the old sealant comes out first
What sand mastic looks like in Lessness Heath
In London conversions and blocks, the lease decides who is responsible for the frames, so check that before booking. Historic houses like Red House (about 2.3 miles south-west) are a reminder that the area around Lessness Heath 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.
For landlords with property near Belvedere station, cracked sand mastic around sash windows lets in the draughts tenants complain about. As a London address, Lessness Heath can be tricky for parking: let us know about parking bays, permits or a driveway.
Lessness Heath is about 3 miles east of Plumstead, in Greater London. Anywhere in DA17, our applicators can take on sand mastic. Across Greater London, we cover 764 places, and Lessness Heath is one of them. Our London page covers work nearby.
We cover every part of the DA17, DA8 and DA7 postcode area for sand mastic and the streets around it. You’ll find streets such as Cray Road, Clive Road and Erith Road, and we cover them all. Nearby, we also carry out sand mastic in Belvedere (1 mile east), Erith (1 mile south-east), Northumberland Heath (1 mile south-east), West Heath (1 mile south-west) and Bexley Riverside (1 mile south-east). We also work in nearby towns such as London (11 miles west), City of Westminster (13 miles west), Marylebone (13 miles west), Kensington (15 miles west), St Pancras (12 miles west) and Shoreditch (10 miles west).
Local landmarks in Lessness Heath
We work in homes and buildings around Priory Club pub, Trinity Church of England School and Trinity School, among other places. Lessness Heath’s nearest station is Belvedere station, about 0.5 miles north. Other landmarks nearby include Broadway Shopping Centre (2.1 miles south) and Erith and District Hospital (0.9 miles south-east). For a walk, there’s Crossness Nature Reserve.