Greater London · England
Sand mastic for sash & case windows in London, Greater London
Problem with your window and door surrounds in London? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Patchy fillers round a sash window
- Tired mastic found when preparing windows for paint
- Modern sealant on a period surround
Sand mastic in London
Fresh sand mastic forms a skin quite soon but full hardening takes longer. Traditional guidance is not to paint over it, so ask us before you decorate. We’re often asked to deal with mastic that needs renewing before redecorating and cement or filler used on old window joints that has cracked, across timber door frames, period & listed homes and brick reveals.
In London, windows range from older timber frames to modern uPVC and aluminium. The mastic around all of them ages, and it’s usually the first thing to let the weather in.
Whatever the size of the job, you get the same 12-month guarantee in London and across Greater London.
- Location
- London (CR0, E14, CR4, SW11)
- Wider area
- Greater London
- Cover
- One year on every job
- Quotes
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
How we quote for sand mastic
Call for a quick quote. What matters most is:
- How much old sealant there is and how hard it is to remove
- When we can work, for business premises
- The size of the job
- Whether there’s mould to deal with
Every job is a little different, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all play a part.
Helping us quote
When you contact us, it’s useful to know:
- Whether it’s a home or a business
- What the problem is, such as mould, gaps, leaks or cracking
- Roughly how big the job is
- A few pictures by email, if you can
It all starts with a short chat. Describe the problem, the location and the size of the job, and we will explain how we’d tackle it. When it suits you, ring 0345 464 0079 or email us.
How the visit works
At the end, we look at the finished work together. The visit itself normally takes a few hours for a single window, longer for several, depending on how much there is to do. Jobs in a place the size of London range from town-centre flats to offices and family homes. Whichever it is, tell us how to get in, where to park and where the work is.
- We check each window surround and the condition of the joint.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic isn’t too thick.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
Getting ready for the visit
- Tell us about any previous sealing or DIY attempts
- For indoor joints, keep the area dry beforehand if you can
- Keep pets and children clear of the area while we work
Getting a quote
We quote each job on its own, so the first step is telling us about yours. Just phone 0345 464 0079 or email us with the details, and pictures are welcome.
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Questions from London
Do you work for landlords with property near Elephant & Castle station?
Yes. We work for landlords and agents as well as householders. Just ring 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear quote.
Can you do sand mastic in London?
Yes, London is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job.
Are you an approved applicator?
Yes. We are ARBOMaster approved, the scheme for applicators of Arbo sealants.
Should I try DIY first?
It depends on the job. Work at height, movement joints, fire-rated gaps and large areas are best left to a professional.
Should I use sand mastic or silicone?
We’ll help you decide. Sand mastic suits many period homes, and modern sealants suit newer frames.
Do you offer different sealant colours?
We help you choose a colour that suits. The product needed can limit the range.
Will you leave a mess?
Tidy work is part of the job. We protect what’s around the joints.
What’s sand mastic made of?
A traditional pointing material made from sand and a linseed-oil-based binder for the joint between timber frames and masonry.
Places near London
Other services in London
What we’re called out for in London
Most of it is simply age. Even well-laid mastic needs renewing in time, depending on exposure and upkeep.
Look out for any of the following:
- Old cement repairs round a window that have failed
- Gaps round a timber door in stone or brick
- Window mastic to renew ahead of painting
- Mastic dropping out of the joint
If you let a flat or house near Elephant & Castle station, older sash windows in a rental need their mastic kept sound to keep the weather out.
What to look for in a quote
- Is the old sealant removed completely?
- How the joint is cleaned and prepared
- When the joint can take water or movement
- How the colour is chosen
What sand mastic looks like in London
With historic houses such as Mansion House (about 1 mile north) nearby, there’s older building stock in the area around London 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. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
If you live in an older home near St George the Martyr, the joint between an old wall and a newer frame is generally the first place rain gets in. For site and facilities teams at buildings such as Charles Dickens Primary School, its window and door frames need their mastic kept sound, just like a home’s.
London is in Greater London. Wherever you are in the CR0 postcode area, our applicators can take on sand mastic. Our area takes in 764 places across Greater London, from the larger towns to small villages.
We cover every part of CR0, E14, CR4 and SW11 for sand mastic and the streets around it. You’ll find streets such as Walcot Square, Surrey Square and Sutherland Square, and we cover them all. London is on the A2 and A10, which makes it straightforward to reach with everything needed for sand mastic. Other places close to London include Walworth (1 mile south), Bermondsey (1 mile east), Camberwell (2 miles south), South Bermondsey (2 miles south-east) and Surrey Canal (2 miles south-east). Further out, we also cover City of Westminster (3 miles west), Marylebone (3 miles north-west), Kensington (5 miles west), Walthamstow (7 miles north-east), Hampstead (5 miles north-west) and Ruislip (14 miles west). London is among the bigger towns we cover in Greater London.
Near you in London
In London, that means homes and buildings near Newington Gardens, Trinity Arms Public House and London School of Musical Theatre. You will also find St Mary-at-Hill (0.9 miles north-east), Ark Globe Academy (under half a mile south) and The BFI Reuben Library (1 mile north-west). There’s a railway station in London itself: Elephant & Castle station. Other landmarks nearby include Surrey Dispensary (under half a mile south-east) and Baynard's Castle (0.9 miles north). Green spaces nearby include Bellenden Road Nature Garden and St. James's Park Lake.
Work for landlords, hotels and businesses
Whether it’s one flat or a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
When something else is needed
We’ll always be straight with you, so here’s what new sealant will not do:
- Damaged stone surrounds
- Broken panes
- Sash cords, weights and draught-proofing of the sashes
If in doubt, call 0345 464 0079 or email us and we’ll say what we think.
Joints and surfaces we work on
- Timber door frames
- Tenement windows
- Brick reveals
- Sash and case windows
- Stone surrounds
- Period & listed homes
Keeping the joints in good condition
How long the joints last depends on use and care. Here’s what we suggest:
- Ask a joiner to look at soft timber first
- Plan mastic work ahead of painting
- Ask the planning authority about consent for listed or conservation-area homes
- Look over the window mastic once a year
Check the mastic when you check the paintwork. Catching cracks early keeps repairs small.
It’s best to renew mastic before painting the windows. Painting over failed mastic hides the problem for a while.
What the job involves on each 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.
Timber door frames
Door frames get knocked and soaked and the mastic can crack early. We rake it out and renew it.