Greater London · England
Sand mastic for sash & case windows in Bexley Riverside, Greater London
Sand mastic across Bexley Riverside and nearby, with old sealant always removed completely.
- Old cement repairs round a window that have failed
- Silicone on a period window that looks wrong
- Cracked mastic round a front door frame
Sand mastic for homes and businesses in Bexley Riverside
Our applicators renew the sand mastic around sash and case windows and doors in stone and brick. The old mastic is raked out, and new mastic is applied and shaped by hand. We are often asked to deal with crumbling sand mastic round a window and cracked mastic round a front door frame, on tenement windows, sash and case windows and stone surrounds.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
Each job carries a 12-month guarantee.
- Place
- Bexley Riverside (DA8, DA7, DA1)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
What affects the cost of sand mastic
For a quick quote, just ask. The main things that affect it are:
- How much old sealant there is and how hard it is to remove
- Mould in or behind the old joints
- How many rooms, windows or areas are involved
- Which sealant suits the joint
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Asking for a quote
What to tell us when you ask for a quote:
- Access, such as stairs, a lift or height
- How many joints, rooms or windows are involved
- Where the property is
- If someone has resealed it before
Asking for a quote is easy: let us know what needs doing and where and its rough size. A few pictures by email make the job easier to understand, and we will come back to you with a quote.
Windows and doors in Bexley Riverside
Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
For site and facilities teams at buildings such as Normandy Primary School, larger buildings have plenty of frames, and the mastic around each one ages. For an older house near a landmark such as St Paul's, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Bexley Riverside is about 3 miles north-west of Dartford, in Greater London. Bexley Riverside gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Bexley Riverside is one of 764 places in Greater London we cover. For nearby work, see our London page.
We cover every part of the DA8, DA7 and DA1 postcode area for sand mastic. Whether your property is on Mill Road, Hurst Road and Bexley Road or anywhere close by, we can help. Neighbouring places we cover for sand mastic include Northumberland Heath (1 mile north-west), Barnehurst (1 mile south), Erith (1 mile north), North End (1 mile east) and Slade Green (1 mile east). We also work in nearby towns such as London (12 miles west), City of Westminster (14 miles west), Marylebone (14 miles west), St Pancras (13 miles west), Shoreditch (11 miles west) and Walthamstow (12 miles north-west).
Around Bexley Riverside
Locally, jobs take us to homes and businesses close to Braeburn Park, The Royal Oak pub and Trinity School. For rail, the closest station is Barnehurst station, about 0.6 miles south-west of the centre. A little further out are Broadway Shopping Centre (1.4 miles south-west) and Erith and District Hospital (0.5 miles north). The countryside around Bexley Riverside includes Wansunt Pit.
For landlords and businesses
We also work for businesses, from offices to washrooms and kitchens. For commercial premises, we can talk through working times when we quote.
Whether it’s one flat or a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a 12-month guarantee.
How to look after the new joints
To keep the joints looking good and working properly:
- Check the mastic when you check the paintwork
- Plan mastic work ahead of painting
- Have rotten timber repaired before new mastic goes in
- Keep sills and gutters clear so water drains away
Avoid painting over the new mastic, as traditional guidance advises. Ask us before any decorating around it.
Once mastic starts to crumble, rain gets in. It can soak into the frame and the surrounding masonry so early renewal protects both.
Places near Bexley Riverside
What else we do in Bexley Riverside
Questions from Bexley Riverside
Is Bexley Riverside in your area for sand mastic?
Yes. We work across London and the South East, and Bexley Riverside is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job, and we will send you a clear quote.
Can you help a landlord with a rental near Barnehurst station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or email us and tell us about the property, and we will give you a clear price.
Is sand mastic better than silicone for my windows?
For period timber windows in stone or brick, sand mastic is often the better fit. On modern frames, we’d normally use a flexible sealant.
Can new sealant go over the old?
No, and we never do. It may look fine at first, but the new bead soon lifts. The old sealant has to come out completely.
How long does sand mastic take?
As a guide, most jobs take anything from a few hours to a full day, depending on how many windows. Larger jobs naturally take longer.
What is sand mastic?
Sand mastic is a traditional material for pointing round windows and doors. It combines sand with a linseed-oil-based binder.
Is it possible to take out silicone and use sand mastic instead?
Usually, yes. Once the silicone is out and the joint prepared, sand mastic is applied by hand.
Are you fully insured?
Yes. Mr Mastic is fully insured, and we’ve been doing sealant work for more than 20 years.
What happens if it’s left?
An open joint round the frame lets weather in. Left, water can reach the timber and the wall, so dealing with it now protects both. Damp from a failed joint spreads quietly in older London brickwork and timber, and by the time it shows on a wall or ceiling in Bexley Riverside, the repair is bigger than the sealant job would have been.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, plus any working-time requirements on site. Ask us for a quote and we will go through it with you.
Why choose Mr Mastic in Bexley Riverside
- Anti-fungal sanitary silicone in wet areas
- Tidy, careful work
- Over 20 years’ experience
- We’re fully insured
Take a look at our cost guide or our reviews.
How it works
A visit follows a simple pattern: we check the joints, mask and protect the surrounding surfaces, do the work and tidy away. It generally takes a few hours per window, depending on the condition of the joints. In Bexley Riverside, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- Large voids are packed out.
- New sand mastic is applied and shaped by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Tell us if parking is tricky
- Let us know about earlier repairs to the joints
- Tell us about any water getting in
Ask for a quote
Need a quote? Please ring 0345 464 0079 or send us an email and tell us about the job. We will explain what we’d do and give you a clear quote before work begins.
Related advice
When to call us in Bexley Riverside
Over the years, sand mastic weathers. It dries out, cracks and loses its grip from the frame or the masonry.
Any of these means the joints need attention:
- Silicone on a period window that looks wrong
- Failed mastic on an exposed elevation
- Window mastic to renew ahead of painting
- Gaps where the frame meets the masonry
As a London address, Bexley Riverside can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Before you book anyone
- Whether all the old sealant comes out first
- How long the guarantee is
- What the cure time is
- What happens if they find a problem under the old sealant
When something else is needed
To be straight with you, some problems need a different trade:
- Broken panes
- Planning or listed building consent (your local planning authority decides)
- Sash cords, weights and draught-proofing of the sashes
If in doubt, call 0345 464 0079 or drop us an email and we’ll say what we think before booking.
Where we work in Bexley Riverside
- Brick reveals
- Period & listed homes
- Sash and case windows
- Tenement windows
- Stone surrounds
- Timber door frames