Greater London · England
Sand mastic for sash & case windows in Lewisham, Greater London
Specialist sand mastic for Lewisham: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Mastic worn away on windows facing the weather
- Patchy fillers round a sash window
- Gaps where the frame meets the masonry
What we do, step by step
Our applicators work methodically: protect, prepare, seal, tidy. For most jobs that takes a few hours per window, depending on the condition of the joints, and the area is left clean. For a job in Lewisham, parking and access are the things to plan: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- Deep voids are packed so the mastic is the right thickness.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- We dress the surface so it sits neatly against the masonry.
Preparing for the visit
- For indoor joints, keep the area dry beforehand if you can
- Mention any leaks or damp you’ve noticed
- Let us know about parking restrictions
Get a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add pictures by email if you can.
Advice
About our sand mastic in Lewisham
We renew sand mastic around sash windows and doors in stone and brick. Out comes the old, loose mastic, and new mastic is applied and shaped by hand. If you have mastic dropping out of the joint and old cement repairs round a window that have failed, we can put it right, on brick reveals, tenement windows and period & listed homes alike.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in.
Big or small, it’s backed by our one-year guarantee.
- Where
- Lewisham (SE13, SE8, SE6)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Price
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
What sealant work cannot fix
We will always be straight with you, so here’s what sealant can’t fix:
- Masonry that needs repairing
- Sash cords, weights and draught-proofing of the sashes
- Planning or listed building consent (your local planning authority decides)
If in doubt, ring 0345 464 0079 or email us and we’ll say what we think.
What we seal
- Timber door frames
- Period & listed homes
- Stone surrounds
- Brick reveals
- Sash and case windows
- Tenement windows
Your questions about sand mastic in Lewisham
I let a flat near Lewisham station. Can you help?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just call 0345 464 0079 or email us with the address and what needs doing, and we’ll give you a clear quote.
Can parking be tricky for a visit in Lewisham?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot.
Is the work guaranteed?
There’s a 12-month guarantee on every job, sand mastic included.
Do I need permission for sand mastic on a listed building?
Speak to your local planning authority before work starts. Like-for-like sand mastic is often the preferred finish, but they decide.
What do you put in the joint?
It depends on the joint: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. We use products from Arbo and Everbuild.
Do you come to Lewisham?
Yes. From our base in Crawley, we cover South East England, London and all of Scotland, Lewisham included.
What do you need from me for a quote?
Just the basics: the address or postcode, what’s wrong and any access issues. After that, simply ring 0345 464 0079 or drop us an email.
Can I choose the sealant colour?
Most of the time, yes. We’ll tell you which colours the right product comes in and agree one before work begins.
When to call us in Lewisham
Decorating can disturb tired mastic. It’s often found when windows are being prepared for paint, which is a good time to renew it.
Most people get in touch after spotting one of these:
- Cement or filler used on old window joints that has cracked
- A silicone bead on a sash window that spoils the look
- Draughts and rain around sash boxes
- Cracked mastic round a front door frame
As a London address, Lewisham can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Before booking anyone
- How long to leave it before use
- How the joint is cleaned and prepared
- What guarantee comes with the work
- How the colour is chosen
Also near Lewisham
Also in Lewisham
Landlords, agents and businesses in Lewisham
Failed sealant is one of the commonest items on a check-out report. We can quote for more than one property at once.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance.
What the job involves on each surface
Stone surrounds
Sand mastic sits naturally against stone. The finish blends with the masonry.
Sash and case windows
Sash windows are where we do most sand mastic work. Each joint round the box is raked out and renewed.
What affects the quote in Lewisham
Call for a quick quote. What matters most is:
- How many areas need sealing
- Access and height
- The number and length of the joints
- Whether old sealant or filler has to be cut out
The cost depends on the amount of work, how much old material has to come out and access to the work. You’ll have a clear quote before any work starts.
Asking for a quote
To help us quote quickly, let us know:
- Any access issues, like height or stairs
- The problem you’ve noticed
- Roughly how big the job is
- The address or postcode of the job
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we’ll talk you through what we’d do. Whenever you’re ready, ring 0345 464 0079 or send us an email.
Frames and glazing around Lewisham
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For landlords with property near Lewisham station, cracked sand mastic around sash windows lets in the draughts tenants complain about. For an older house near a landmark such as St Stephen's Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Lewisham is about 3 miles west of Eltham, in Greater London. We carry out sand mastic for homes and businesses in Lewisham and the surrounding area. Our area takes in 764 places across Greater London, from the larger towns to small villages.
All of SE13, SE8 and SE6 is within our area for sand mastic, from the main roads to the quietest streets. Streets in the area include Station Road, Lewisham High Street and Lewis Grove. Being close to the B220, Lewisham is easy for our applicators to reach. Neighbouring places we cover for sand mastic include Ladywell (1 mile south-west), St Johns (1 mile north-west), Hither Green (1 mile south-east), Blackheath (1 mile north-east) and Lee (1 mile south-east). Larger places within reach include London (4 miles north-west), City of Westminster (7 miles north-west), Marylebone (7 miles north-west), Kensington (9 miles west), St Pancras (6 miles north-west) and Shoreditch (5 miles north-west).
Local landmarks in Lewisham
Around Lewisham, our work takes us to homes and buildings near St Joseph's Academy, Ladywell Fields and The Watch House, among other places. There’s a railway station in Lewisham itself: Lewisham station. A little further out are Greenwich Castle (1.2 miles north) and Fan Museum (1.2 miles north). The countryside around Lewisham includes Knight's Hill and Brookmill Road Local Nature Reserve.
Can I do it myself?
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.