Greater London · England
Sand mastic for sash & case windows in Horn Park, Greater London
Sand mastic for Horn Park, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Mastic dropping out of the joint
- Open joints round the window box
- Wind and rain getting in round a sash window
Sand mastic in Horn Park, done properly
Sand mastic is the traditional way to point the gap between a timber window frame and the stone or brick around it. It’s a mix of sand and a linseed-oil-based binder, applied by hand. On period homes, it looks right where silicone wouldn’t. Typical jobs include cement or filler used on old window joints that has cracked and silicone on a period window that looks wrong, across period & listed homes, brick reveals and timber door frames.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out.
A 12-month guarantee comes as standard.
- Place
- Horn Park (SE12, SE9, SE3)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Why deal with it now?
New mastic over crumbling mastic will not hold. We remove the loose material first so the new mastic stays put. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble for homes in Horn Park.
Leaving a failed joint normally makes the job bigger, not smaller. If you are not sure whether it needs doing, call 0345 464 0079 or drop us an email for an honest opinion and a quote.
Why us?
- 12-month guarantee on every job
- ARBOMaster approved applicator
- We never seal over old sealant
- Homes, businesses and hotels
Read what affects the cost or customer reviews.
Work for landlords, hotels and businesses
In hotels, rooms out of use cost money, so the work can be planned room by room around your bookings where we can. We’ve worked in hotels as well as homes and businesses.
We regularly work with letting and managing agents. Tell us the address, the job and how access works and we’ll give you a quote.
What sealant work can’t fix
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Crumbling stone or brickwork round the window
- Sashes that rattle, stick or won’t open
- Decisions on consent for listed homes
If you’re not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer before you book.
Where we work in Horn Park
- Period & listed homes
- Stone surrounds
- Brick reveals
- Tenement windows
- Timber door frames
- Sash and case windows
Towns and villages near Horn Park
Other services in Horn Park
Questions from Horn Park
I let a flat near Lee station. Can you help?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. You can ring 0345 464 0079 or send us an email with the details for a clear quote.
Can parking be tricky for a visit in Horn Park?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Can you quote for more than one area?
Yes. More than one area can be quoted together.
Can new sealant go over the old?
No. The old sealant always comes out first, so the new joint bonds to clean surfaces.
What information do you need?
A short description and the location, with photos by email if possible. If we need more, we will ask.
Is it possible to take out silicone and use sand mastic instead?
Often, yes. With the silicone removed and the joint cleaned we point it with sand mastic.
Do the sealants smell?
Sometimes, a little. Any smell clears as the sealant cures.
How long does the job take?
That depends on the amount of work, but most jobs take anything from a few hours to a full day, depending on how many windows. We will tell you when we quote.
Different surfaces, different methods
Sash and case windows
Most of our sand mastic work is on sash windows. Each joint round the box is raked out and renewed.
Tenement and terrace windows
Upper-floor windows need access planning. Tell us the height and we will confirm what’s needed.
Common problems we fix in Horn Park
Most of it is simply age. Even well-laid mastic needs renewing in time and how long it lasts depends on the weather it faces.
Common reasons people contact us include:
- Mastic worn away on windows facing the weather
- Wind and rain getting in round a sash window
- Patchy fillers round a sash window
- Gaps where the frame meets the masonry
Managing a site like Horn Park Primary School? Then its window and door frames need their mastic kept sound, just like a home’s.
What your quote should include
- Which colour the sealant will be
- The length of the guarantee
- What product goes in the joint
- Is VAT in the price?
What we do, step by step
When we get to you, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. Most jobs then take anything from a few hours to a full day, depending on how many windows. In Horn Park, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- First, we look at the surrounds with you and agree what needs doing.
- We rake out the old mastic and clean the joint.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
How to prepare
- Where the joints are inside, avoid wetting them before we arrive
- Mention any sign-in or site rules at work premises
- Mention any leaks or damp you’ve noticed
Getting a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add pictures by email if you can.
Advice
Frames and glazing around Horn Park
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Letting a property close to Lee station? Then older sash windows in a rental need their mastic kept sound to keep the weather out. In the older streets around Church of St Saviour, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Horn Park is about 1 mile west of Eltham, in Greater London. From the centre of Horn Park to the outskirts, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. Our Greater London coverage runs to 764 places, Horn Park among them. Our London page covers work nearby (6 miles or so).
Here we cover the SE12, SE9 and SE3 postcode area for sand mastic. We cover properties on Winn Road, Horsa Road and Guibal Road. If you are just outside Horn Park, we cover Middle Park (1 mile east), Lee (1 mile north-west), Mottingham (1 mile south-east), Chinbrook (1 mile south) and Grove Park (1 mile south). We also work in nearby towns such as London (6 miles north-west), City of Westminster (9 miles north-west), Marylebone (9 miles north-west), Kensington (10 miles west), St Pancras (8 miles north-west) and Shoreditch (7 miles north-west).
Around Horn Park
Typical jobs here are in homes near Manor House Gardens, Colfe's School and Harris Academy Greenwich and the streets around them. For rail, the closest station is Lee station, about 0.5 miles west of the centre. Nearby you will also find Greenwich Castle (2.4 miles north-west) and Lewisham Shopping Centre (1.9 miles north-west). Not far away are Summer Hill and Birdbrook Road Nature Reserve.
Can I do it myself?
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.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.