Greater London · England
Sand mastic for sash & case windows in Ashburton, Greater London
Sand mastic in Ashburton 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
- Mastic that needs renewing before redecorating
- Cracked mastic round a front door frame
How we handle sand mastic in Ashburton
Sand mastic does not last for ever and gaps open up round the frame. Renewing it closes the gap so the surround looks right again. We’re often asked to deal with cement or filler used on old window joints that has cracked and draughts and rain around sash boxes, across period & listed homes, tenement windows and sash and case windows.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease usually says who is responsible for the windows, so it’s worth checking before booking.
Big or small, it’s backed by our 12-month guarantee in Ashburton and across Greater London.
- Where
- Ashburton (CR0, SE25, CR9)
- Region
- Greater London
- Guarantee
- A year, on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
How to look after the new joints
Aftercare is simple, and it makes a real difference:
- Take care around the mastic when scraping paint
- Sort the mastic before the decorators arrive
- Find out about consent before window work on a listed home
- Don’t paint over the new mastic
Leave the new mastic alone while it firms up. It forms a skin fairly soon but needs longer to fully harden.
Sound mastic protects the frame. Once it fails, water can sit against the timber and timber that stays wet can rot.
Honest limits
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Masonry that needs repairing
- Decayed frames that need repair
- Broken panes
If you’re not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
Joints and surfaces we work on
- Tenement windows
- Stone surrounds
- Sash and case windows
- Timber door frames
- Period & listed homes
- Brick reveals
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 does not work out, we can still put it right.
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.
How we quote for sand mastic
Every job gets its own quote. This is what makes a difference:
- The product the joint needs
- The size of the job
- When we can work, for business premises
- Access and height
Leaving a failed joint usually makes the job bigger, not smaller, because water and mould keep working on it. If you are not sure whether it needs doing, call 0345 464 0079 or email us and we will give you an honest view and a quote.
Asking for a quote
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- The address or postcode of the job
- If it’s domestic, commercial or a hotel
- Pictures of the joints, sent by email
- Any previous sealing or DIY work
Call for a quick quote, or email us if that is easier. Describe what needs sealing and we will explain what’s involved and give you a clear price.
The process
When we arrive, we look over the joints with you first, so there are no surprises. Surfaces next to the work are protected before we start. The work generally takes a few hours per window, depending on the condition of the joints. In a London area like Ashburton, the main things to plan are parking and access: let us know about parking, the floor we will be working on and any lift or shared entrance.
- First, we look at the surrounds with you and agree what needs doing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- We pack any deep gaps so the mastic sits at the right depth.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- The finish is dressed so it sits neatly against the stone or brick.
Getting ready for the visit
- For indoor joints, keep the area dry beforehand if you can
- On commercial sites, let us know about site rules
- Tell us about any water getting in
Getting a quote
It all starts with a short chat. Tell us what’s wrong, where it is and how much there is. Whenever you’re ready, call 0345 464 0079 or email us.
Advice
Ashburton: your questions answered
Is parking an issue for sand mastic in Ashburton?
Parking in Ashburton, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot.
Do you work for landlords with property near Norwood Junction station?
Yes, landlords and agents are among the people we work for. You can phone 0345 464 0079 or email us with the details for a clear quote.
Which products do you use?
The product depends on the job: sanitary silicone where it gets wet, and sealants suited to movement or weather elsewhere. Brands we use include Arbo and Everbuild.
What should I tell you?
Only a few details: where it is, what you’ve noticed and how we reach it. After that, simply call 0345 464 0079 or email us.
What is sand mastic?
Sand plus a binder based on linseed oil. It’s applied by hand and shaped to suit the surround.
How long does sand mastic take?
It depends on the size of the job, but most jobs take a few hours per window, depending on the condition of the joints. We’ll give you a better idea when we quote.
Is there any odour?
Possibly a little. Any smell clears as the sealant cures, and ventilation helps.
Will it make a mess?
Not at all. The area is protected while we work and cleaned up afterwards.
Surface by surface
Period and listed homes
Sand mastic is the like-for-like choice for many period homes. If your home is listed, ask your local planning authority about consent.
Stone surrounds
Stone openings are rarely perfectly straight, so the gap is not the same all the way round. Sand mastic is shaped by hand to suit.
Places near Ashburton
Also in Ashburton
Ashburton homes and the weather
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. Historic houses like Addington Palace (about 2.4 miles south-east) are a reminder that the area around Ashburton has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
Rented homes near Norwood Junction station change hands often, and cracked sand mastic around sash windows lets in the draughts tenants complain about. Homes close to Church of St Luke include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Ashburton is about 6 miles south of New Cross, in Greater London. Ashburton gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Our area takes in 764 places across Greater London, from the larger towns to small villages. You can also see our page for London, roughly 8 miles from Ashburton.
Every address in CR0, SE25 and CR9 is within our area for sand mastic, from the main roads to the quietest streets. Whether your property is on Long Lane, Tudor Road and Coe Avenue or a nearby road, we can help. We also cover the places around Ashburton: Woodside (1 mile north), Addiscombe (1 mile south), Shirley Oaks (1 mile south-east), Monks Orchard (1 mile south-east) and Shirley (1 mile south-east). Further out, we also cover London (8 miles north), City of Westminster (9 miles north-west), Marylebone (10 miles north), Kensington (10 miles north-west), St Pancras (10 miles north) and Shoreditch (10 miles north).
What’s near Ashburton
Typical jobs here are in homes near Oasis Academy Shirley Park, Ashburton Park and The Beehive pub. The nearest railway station is Norwood Junction station, about 0.7 miles north-west of the centre. Well-known places in the area include National Psychosis Unit (1.7 miles east) and Whitgift Centre (1.6 miles south-west). Not far away are Duppas Hill and Bramley Bank.
When to call us in Ashburton
Shallow joints are a common cause. A thin layer doesn’t hold well, which is why we pack deep voids first and get the depth right.
Most people get in touch when they notice something like this:
- Draughts and rain around sash boxes
- Old sand mastic that has cracked, crumbled or fallen out
- Gaps where the frame meets the masonry
- Mastic round period door frames that has failed
As a London address, Ashburton can be tricky for parking: let us know about parking bays, permits or a driveway.
What to look for in a quote
- Whether they’re fully insured
- When the joint can take water or movement
- How the surfaces are prepared before sealing
- Which sealant they’ll use, and why