Greater London · England
Sand mastic for sash & case windows in Green Street Green, Greater London
Problem with your window and door surrounds in Green Street Green? We remove the old material, prepare the joints and seal them properly, with a 12-month guarantee.
- Gaps between timber frames and stone or brick
- Wind and rain getting in round a sash window
- Failed mastic on an exposed elevation
Looking after it afterwards
Simple care keeps the joints in good condition. Our advice:
- Don’t run silicone over sand mastic
- Check with your local planning authority if your home is listed
- Leave the new mastic unpainted
- Plan mastic work ahead of painting
When preparing windows for paint, take care around the mastic. It can be damaged by heavy scraping.
An open joint round the box lets weather through. Left, the gap tends to get bigger as more mastic falls out.
Sand mastic for homes and businesses in Green Street Green
On many period windows, sand mastic looks right and suits the building. On modern frames we’d normally use a flexible sealant and we’ll explain which is best for yours. We’re often asked to deal with mastic round period door frames that has failed and modern sealant on a period surround, across stone surrounds, tenement windows and timber door frames.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. The mastic around them dries out and cracks with age, letting in draughts and water.
We stand behind the work with a 12-month guarantee.
- Place
- Green Street Green (BR6)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
How the job changes by surface
Sash and case windows
The mastic round a sash window is on show, so a neat, even finish matters.
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair, so check who is responsible first.
For landlords and businesses
Hotels need rooms back in use, so the work can be planned room by room. We have worked in hotels as well as homes and businesses.
Letting agents often deal with us directly. Send the address, what’s needed and the access arrangements and we’ll quote.
How it works
Good joint work is mostly preparation, so that is where we spend the time. Every joint is cleaned and dried before new material goes in. In total, it generally takes a few hours per window, depending on the condition of the joints. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Green Street Green. A visitor permit or a nearby bay makes the visit run more smoothly.
- We check each window surround and the condition of the joint.
- We rake out the old mastic and clean the joint.
- We fill deep gaps so the new mastic isn’t too thick.
- New sand mastic is applied and shaped by hand.
- We finish the mastic to a tidy line.
How to prepare
- Keep pets and children clear of the area while we work
- Let us know about parking restrictions
- Tell us about any water getting in
Ask for a quote
Want a quote for sand mastic? Please phone 0345 464 0079 or send us an email with a few details. You will know what we plan to do, and what it will cost, before any work begins.
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Also near Green Street Green
Also in Green Street Green
What we can’t put right
We will not take on work that won’t last, so here’s what sealant can’t put right:
- Decisions on consent for listed homes
- Cracked or broken glass
- Rotten sashes, sills or window boxes (a joiner’s job)
If you are not sure, just call 0345 464 0079 or drop us an email and we’ll give you a straight answer.
Where we work in Green Street Green
- Brick reveals
- Sash and case windows
- Timber door frames
- Tenement windows
- Stone surrounds
- Period & listed homes
Can I do it myself?
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
Sealing over old silicone is the commonest DIY error. Silicone does not stick to old silicone, so it peels away and traps moisture behind it. All the old material has to come out first.
What we are called out for in Green Street Green
Timber frames move with the seasons. The movement cracks the mastic little by little.
Look out for these signs:
- Mastic that needs renewing before redecorating
- Mastic worn away on windows facing the weather
- Gaps between timber frames and stone or brick
- Wind and rain getting in round a sash window
Green Street Green is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book.
What to look for in a quote
- Is VAT in the price?
- Is the old sealant removed completely?
- Which colour the sealant will be
- How the joint is cleaned and prepared
Green Street Green questions
Can parking be tricky for a visit in Green Street Green?
Parking in Green Street Green, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Do you work for landlords with property near Chelsfield station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just ring 0345 464 0079 or email us with the address and what needs doing, and we’ll give you a clear quote.
Does someone need to be in?
For indoor joints, yes, someone needs to let us in. Once we’ve agreed the job, you do not need to watch us work.
Are you fully insured?
Yes. Mr Mastic is fully insured, with over 20 years’ experience in sealant work.
Is it possible to take out silicone and use sand mastic instead?
Yes, we do this often. All the old silicone is removed first so the mastic can sit properly.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status.
What should I tell you?
Where the job is, what the problem is and roughly how big it is. If you can, email a few photos.
What sealant do you use?
Each joint gets the product that suits it. Where it moves, gets wet or faces the weather makes a difference, and we’ll tell you what we’re using.
Windows and doors in Green Street Green
With historic houses such as Down House (about 2.1 miles south-west) nearby, there’s older building stock in the area around Green Street Green as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.
Letting a property close to Chelsfield station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about. For an older house near a landmark such as St Mary's Church, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Green Street Green is about 2 miles south of Orpington, in Greater London. Green Street Green gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a one-year guarantee. We cover 764 towns and villages across Greater London, large and small. We also work in London, about 13 miles from Green Street Green.
Postcode districts we cover here for sand mastic: BR6. You will find streets such as Vine Road, Laxey Road and Shire Lane. Nearby, we also carry out sand mastic in Farnborough (1 mile north-west), Hazelwood (1 mile south-west), Crofton (2 miles north), Downe (2 miles south-west) and Farthing Street (2 miles west). Within a short drive, we also cover London (13 miles north-west), City of Westminster (15 miles north-west), Marylebone (15 miles north-west), St Pancras (15 miles north-west), Shoreditch (14 miles north-west) and Hoxton (15 miles north-west).
Near you in Green Street Green
Locally, jobs take us to homes and businesses close to Queens Head pub and Hewitt's Chalk Bank, among other places. The nearest railway station is Chelsfield station, roughly 0.9 miles east of the centre. A little further out are Orpington Hospital (0.8 miles north-east) and Crofton Roman Villa (1.5 miles north). Open spaces near Green Street Green include Summer Hill and Downe Bank Nature Reserve.