Greater London · England
Window & door mastic in Clapham, Greater London
Specialist window mastic for Clapham: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Rain getting in at the frame or under the sill
- Old mastic that has gone black or come away
- Cracked internal joints between frame and plaster
Window mastic in Clapham
From a single sill to a whole house of windows, the work is priced before anything is done. To get one, ring 0345 464 0079 or drop us an email with the number of frames and any access details. Typical jobs include water coming in at the bottom corners of a door and gaps between the frame and the inside reveal, across timber windows & doors, composite doors and patio & French doors.
London has a lot of flats and conversions, where windows are often on upper floors. Who looks after the outside of the frames can depend on the lease, so check that first.
All our work is covered by our 12-month guarantee.
- Place
- Clapham (SW4, SW8, SW9)
- Wider area
- Greater London
- Cover
- A year, on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
What we can’t put right
Before you book, it’s worth knowing the limits too:
- A sash or casement that won’t close properly
- Damp problems in the wall away from the window
- Draughts through the window seals rather than the frame
If you’re not sure, just call 0345 464 0079 or drop us an email and we’ll give you a straight answer before you book.
Surfaces we seal
- Aluminium frames
- Patio & French doors
- Window sills
- uPVC windows
- Composite doors
- Timber windows & doors
Clapham homes and the weather
With historic houses such as Carlyle's House (about 1.9 miles north-west) nearby, there’s older building stock in the area around Clapham as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Rented homes near Clapham High Street station change hands often, and sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. If you look after a building such as Clapham Manor Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Clapham is about 3 miles north of Streatham, in Greater London. Wherever you are in the SW4 postcode area, our applicators can take on window mastic. Across Greater London, we cover 764 places, Clapham among them.
We work across SW4, SW8 and SW9 for window mastic and the streets around it. Whether your property is on Grafton Square, Clapham High Street and Houghton Square or a nearby road, our applicators can take on the job. You will find Clapham on the B224 and B303, which makes it straightforward to reach with everything needed for window mastic. If you are just outside Clapham, we cover Stockwell (1 mile east), Little Portugal (1 mile north-east), Clapham Park (1 mile south), South Lambeth (1 mile north-east) and Brixton (1 mile south-east). Further out, we also cover London (3 miles north-east), City of Westminster (3 miles north), Marylebone (4 miles north), Kensington (4 miles north-west), St Pancras (4 miles north) and Shoreditch (5 miles north-east).
Local landmarks in Clapham
Typical jobs here are in homes near Lambeth Academy, Larkhall Park and Trinity Academy. There’s a railway station in Clapham itself: Clapham High Street station. A little further out are Baynard's Castle (3.5 miles north-east) and Harrods (2.6 miles north-west). The countryside around Clapham includes Battersea Park Lake and Knight's Hill.
Leave it or put it right?
Not every sealant suits a window. Interior caulk and bathroom silicone aren’t made for exterior frame joints. A low-modulus exterior sealant keeps its stretch through hot and cold weather. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Clapham, the repair is bigger than a sealant job.
The cost reflects the work involved, not guesswork. That’s why we ask about the job first and give you a clear price before any work starts.
Why book with us
- 20+ years of sealant experience
- Tidy, careful work
- Sanitary silicone with an anti-fungal additive in wet areas
- Rated 4.9 stars on Google
See our cost guide or our reviews.
Common problems we fix in Clapham
Sun, frost and rain wear sealant out. UV light hardens the outside of the bead, and over the years it loses its give, cracks and comes away.
Most people get in touch after spotting one of these:
- Draughts coming in around windows and doors
- Draughty joints inside around the window
- Damp patches on the reveal after heavy rain
- Rushed sealant from a window installation
As a London address, Clapham can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
What to look for in a quote
- How the joint is cleaned and prepared
- How long to leave it before use
- What insurance they hold
- Who does the work, and how experienced they are
What affects the cost of window mastic
Some jobs are bigger than they look, and some smaller. What affects the quote:
- The number of rooms or windows
- The size of the job
- The old material and how stubborn it is
- Any working-time requirements on site
What it costs depends on how much there is to do, how much old material has to come out and access to the work. You will have a clear quote before any work starts, so you know where you stand.
What to tell us for a quote
Photos by email are helpful but not essential. Try to tell us:
- Roughly how big the job is
- The problem you’ve noticed
- Whether it’s a home or a business
- Where the job is, and your postcode
Getting a quote is simple: let us know the job and the location and its rough size. Photos by email help us understand the job, and we’ll take it from there.
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. Everything old must be removed first.
If you’ve already had a go yourself, that is fine. We cut it out and start again, so just mention it when you contact us.
Clapham questions
Is parking an issue for window mastic in Clapham?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
I let a flat near Clapham High Street station. Can you help?
Yes, landlords and agents are among the people we work for. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Do you work in Clapham?
We do. Clapham is part of the area we cover.
Will new mastic stop draughts?
If the draught is coming in around the frame, yes. If it’s coming through the window seals, we’ll tell you.
What sealant do you use?
Quality sealants from brands including Arbo and Everbuild, picked for each joint. We explain the product when we quote.
Are you fully insured?
Yes, we’re fully insured for domestic and commercial work.
Can you seal over the old sealant?
No. New silicone will not bond to old silicone, and anything trapped underneath, including mould and water, stays there. We remove it all first.
Do you seal inside as well as outside?
Yes, we do both. Inside, the joint between frame and plaster is sealed neatly, using a paintable sealant if you want to decorate.
Towns and villages near Clapham
Also in Clapham
What happens on the day
Most of a good job is in the preparation, and we don’t rush it. Every joint is cleaned and dried before new material goes in. In total, it usually takes most of a day for a typical house, less for a few frames. In Clapham, as in most of London, parking needs a little planning. It helps if you can point us to a visitor permit or a bay close to the door.
- We check how each frame can be reached safely.
- All the failed sealant is cut away.
- Frame and wall are cleaned and must be dry before sealing, and primed where the sealant calls for it.
- Deep voids are backed, then the sealant is gunned in.
- We tool the joint so water runs off, then clear up.
Preparing for the visit
- Clear the area around the work
- For indoor joints, keep the area dry beforehand if you can
- Plan for the work area to be out of bounds to pets and children
Get a quote
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we will explain what’s involved.
Advice
Landlord and commercial work in Clapham
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance.
In hotels, rooms out of use cost money, so the work can be planned room by room around your bookings where we can. Hotel work is part of what we do, alongside homes and businesses.