Greater London · England
Sand Mastic in Penge
Sand mastic for Penge and the surrounding area: careful preparation, the right product and tidy work. Call for a quick quote.
- Cement or filler used on old window joints that has cracked
- Old sand mastic that has cracked, crumbled or fallen out
- Window mastic to renew ahead of painting
How to look after the new joints
So the new joints stay in good condition:
- Take care around the mastic when scraping paint
- Do not paint over the new mastic
- Make sure water runs off the sill
- Check with your local planning authority if your home is listed
Make sure water drains away from the window surround. Constant wetting wears the mastic faster.
Once mastic starts to crumble, rain gets in. It can soak into the frame and the surrounding masonry, so renewing it early is worth it.
Sand mastic for homes and businesses in Penge
For a listed home or one in a conservation area, ask your local planning authority whether consent is needed for work to windows. Like-for-like sand mastic is often the preferred finish. We work on brick reveals, timber door frames and stone surrounds, and people most often call us about draughty sash windows at the surround and open joints round the window box.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out.
Whatever the size of the job, it’s backed by our 12-month guarantee.
- Location
- Penge (SE20, SE19, SE26)
- Region
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before we start
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Penge: your questions answered
Can you help a landlord with a rental near Penge West station?
Yes, rental work is part of what we do. Just phone 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear quote.
Is parking a problem for a job in Penge?
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.
Will you leave a mess?
Not at all. We work neatly, protect the area around the joints and tidy up afterwards.
Should I check with the council before work on a listed or conservation-area home?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like, but they decide.
Can old silicone round a sash window be swapped for sand mastic?
In most cases. The silicone is cut out and the joint cleaned before the sand mastic goes in.
Can you do several jobs on one visit?
Yes, we can. More than one area can go on one quote.
What exactly is sand mastic?
A traditional pointing material made from sand and a linseed-oil-based binder for the joint between timber frames and masonry.
What guarantee comes with the work?
Our 12-month guarantee applies on every job.
The process
All our tools and materials come with us in the van. Once we’ve agreed what’s being done, the area is protected and the work begins. Most jobs take a few hours per window, depending on the condition of the joints. In a London area like Penge, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- First we agree which joints need doing.
- We remove the old, loose mastic.
- Deep gaps are packed so the mastic sits at the right depth.
- The sand mastic is mixed and pressed into the joint by hand.
- We dress the finish so it sits neatly against the masonry.
Getting ready for the visit
- For business premises, tell us about site rules or sign-in
- Tell us if parking is tricky
- Let us know about stairs, lifts or work at height
Get a quote
For a quote, call 0345 464 0079 or send us an email and tell us where the job is and what the problem looks like. You’ll have a clear quote before any work starts.
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Work for landlords, hotels and businesses
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we’ll give you a quote.
For anyone letting property in or around Penge, jobs at different addresses can go on one quote. Just tell us the addresses and what each one needs, and pictures by email help.
Leave it or put it right?
Gaps round a sash window let in rain and draughts. Water can get to the frame and the masonry so renewing it early protects the window. In a flat in Penge, failed sealant seldom stays inside your own four walls: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
Leaving a failed joint usually makes the job bigger, not smaller, as water and mould keep getting in. If you’re not sure whether it needs doing, call 0345 464 0079 or email us and we’ll give you an honest view and a quote.
Why us?
- Any old sealant cut out fully, not covered over
- Experience in homes, commercial sites and hotels
- We leave the area clean and tidy
- An ARBOMaster approved applicator
Take a look at our cost guide or what customers say.
Surface by surface
Tenement and terrace windows
Rows of sash windows on tenements and terraces often need renewing together. We work on single windows or whole elevations.
Stone surrounds
Sand mastic sits naturally against stone. The finish blends with the masonry.
What sand mastic looks like in Penge
In London conversions and blocks, the lease decides who is responsible for the frames, so check that before booking. Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
If you look after a building such as Harris Primary Academy Crystal Palace, larger buildings have plenty of frames, and the mastic around each one ages. In the older streets around Church of St John the Evangelist, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Penge is about 1 mile west of Beckenham, in Greater London. Penge gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Our Greater London coverage runs to 764 places, Penge among them. For nearby work, see our London page.
Postcode districts we cover here for sand mastic: SE20, SE19 and SE26. Streets in the area include High Street, Anerley Station Road and Station Road. Main roads around Penge include the A234, so getting to you is simple. Close by, we work in Anerley (1 mile west), Crystal Palace (1 mile north-west), Sydenham (1 mile north), Gipsy Hill (1 mile north-west) and Upper Norwood (1 mile west). Within a short drive, we also cover London (6 miles north), City of Westminster (8 miles north-west), Marylebone (8 miles north-west), Kensington (8 miles north-west), St Pancras (8 miles north) and Shoreditch (8 miles north).
Local landmarks in Penge
Typical jobs here are in homes near Crystal Palace School, Crooked Billet pub and Crystal Palace Dinosaurs, among other places. There’s a railway station in Penge itself: Penge West station. Well-known places in the area include St Christopher's Hospice (0.5 miles north) and Crystal Palace Museum (0.8 miles north-west). Not far away are Dulwich Upper Wood and Knight's Hill.
Also in Penge
Honest limits
A few problems are outside what sealant work can do:
- Planning or listed building consent (your local planning authority decides)
- Putty and glazing repairs
- Masonry that needs repairing
If in doubt, ring 0345 464 0079 or email us and we will say what we think before booking.
Surfaces we seal
- Brick reveals
- Sash and case windows
- Tenement windows
- Period & listed homes
- Stone surrounds
- Timber door frames
Common problems we fix in Penge
Scraping and sanding before painting can loosen old mastic. It’s often found when windows are being prepared for paint, which is a good time to renew it.
Any of these means the joints need attention:
- Tired mastic found when preparing windows for paint
- Cracked mastic round a front door frame
- Old cement repairs round a window that have failed
- A silicone bead on a sash window that spoils the look
Rented homes near Penge West station change hands often, and cracked sand mastic around sash windows lets in the draughts tenants complain about.
What your quote should include
- What happens if the job turns out different
- Whether VAT is included
- Which colour the sealant will be
- How much experience the applicator has