Greater London · England
Window Mastic in Wandsworth
Mastic around window and door frames, sills and patio doors in Wandsworth, with a 12-month guarantee on every job. Call for a quick quote.
- Rain getting in at the frame or under the sill
- Gaps where the sill meets the wall
- Draughts coming in around windows and doors
Window mastic in Wandsworth, done properly
Homes in Wandsworth have every kind of window: uPVC, aluminium, timber and composite, plus patio doors, French doors and sills. Each gets a sealant chosen for the frame and the wall it meets. If you’re dealing with cold air getting in at the frame edge and untidy mastic left by window fitters, we can put it right, on uPVC windows, patio & French doors and composite doors alike.
London’s Victorian and Edwardian terraces were built with timber sash windows, and many still have them or their replacements. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out.
All our work is covered by our one-year guarantee, wherever you are in Greater London.
- Place
- Wandsworth (SW18, SW15, SW11)
- Region
- Greater London
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Looking after it afterwards
No joint lasts for ever, but care makes a real difference. A few tips:
- Make sure the drainage slots are not blocked
- Wash the frames with mild soapy water
- Look round the frames every year or so
- Don’t use solvent cleaners on the joint
Try not to touch the new joint while it cures, following the cure time we give you. Do not point a pressure washer at the joints.
Leaks normally show up in wet, windy weather, but resealing works best in dry conditions. Dealing with it when you first notice a crack avoids chasing leaks through the wet months.
Wandsworth: your questions answered
Is parking a problem for a job in Wandsworth?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Do you cover Wandsworth for window mastic?
Yes, Wandsworth is within the area we cover. We work across London and the South East. You can ring 0345 464 0079 or drop us an email and tell us what needs doing.
Can you work on commercial sites?
Yes. We’ve worked for hotels, offices and other businesses and we are fully insured.
Do you take out the old sealant first?
Yes. Sealing over old sealant is the main reason resealing fails early, so we never do it.
Can I do it myself?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
What should I tell you?
A short description and the location. If we need more, we’ll ask.
Can you do upstairs windows?
Yes, in most cases. We plan safe access before the job.
Do I have to be there?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
When something else is needed
Honest advice matters more to us than a booking, so here’s what new sealant will not do:
- Draughts through the window seals rather than the frame
- Damp problems in the wall away from the window
- Rotten timber, which needs a joiner first
If you’re not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer before booking.
What we seal
- Window sills
- uPVC windows
- Aluminium frames
- Timber windows & doors
- Patio & French doors
- Composite doors
The process
There isn’t much for you to do on the day. Point us to the joints and we will get on with it. The job generally takes a few hours for a handful of frames, longer for a whole house, including the tidy-up. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- First we look at every frame and agree the list.
- We remove the old mastic and clean the frame and the wall.
- We fit backing rod in deep gaps so the sealant is the right depth.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- We clear up and check every joint is fully closed.
Preparing for the visit
- Let us know about earlier repairs to the joints
- For indoor joints, keep the area dry beforehand if you can
- Tell us about any water getting in
How to get a quote
We do not publish a price list. Instead, we give you a clear price for your job. To get started, call 0345 464 0079 or send us an email.
Related advice
When to call us in Wandsworth
Plenty of failed mastic was poorly applied in the first place. Mastic laid onto dusty, damp or crumbling surfaces never bonded as it should, so it comes away long before its time.
Most people get in touch after spotting something like this:
- Mastic that is falling out in pieces
- Gaps between the frame and the inside reveal
- Rain getting in at the frame or under the sill
- Cracked sealant at the sill ends
As a London address, Wandsworth can be tricky for parking: let us know about parking bays, permits or a driveway.
Comparing quotes
- How the colour is chosen
- Whether the sealant suits the joint
- How long the guarantee is
- How much experience the applicator has
Landlord and commercial work in Wandsworth
Housing providers, facilities teams and property managers book us too in Wandsworth and across Greater London. Several sites can go on one quote.
We work for landlords and letting agents as well as homeowners. Sealant work between tenants keeps a property looking cared for.
How we quote for window mastic
For a quick quote, just ask. The main things that affect it are:
- Mould in or behind the old joints
- How much old sealant there is and how hard it is to remove
- The number and length of the joints
- The type of sealant required
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether we need extra access for height. We take all of that into account in your quote.
What we need to know
Before you ask for a quote, have a think about:
- Whether it has been sealed before
- Access, such as stairs, a lift or height
- Roughly how big the job is
- Pictures of the joints, sent by email
For a quote, ring 0345 464 0079 or drop us an email with the location and a short description of the problem. We’ll give you a clear price before any work starts.
DIY sealant or a professional job?
Sealing over old silicone is the commonest DIY error. New silicone won’t bond to old, so it peels away and traps moisture behind it. Everything old must be removed first.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
Also near Wandsworth
More services for Wandsworth
Wandsworth homes and the weather
Historic houses like Fulham Palace (about 1.5 miles north-west) are a reminder that the area around Wandsworth has older buildings as well as new. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window. In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
Rented homes near Wandsworth Town station change hands often, and cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. For site and facilities teams at buildings such as St Anne's CofE Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Wandsworth is about 3 miles south-west of Brompton, in Greater London. Jobs in Wandsworth get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. We cover 764 towns and villages across Greater London, large and small.
Every address in SW18, SW15 and SW11 is within our area for window mastic, from the main roads to the quietest streets. That includes homes and businesses on Alma Road, Marl Road and Knoll Road and the roads around them. We also cover the places around Wandsworth: Southfields (1 mile south), Earlsfield (1 mile south), Hurlingham (1 mile north), Clapham Junction (1 mile north-east) and Battersea (1 mile north-east). Further out, we also cover London (5 miles north-east), City of Westminster (4 miles north), Marylebone (5 miles north-east), Kensington (3 miles north), St Pancras (6 miles north-east) and Shoreditch (7 miles north-east).
Near you in Wandsworth
In Wandsworth, that means homes and buildings near Ashcroft Technology Academy, Emanuel School and Spread Eagle pub, among other places. There’s a railway station in Wandsworth itself: Wandsworth Town station. Other landmarks nearby include Southside Wandsworth (under half a mile west) and Antique Breadboard Museum (1.4 miles north-west). Not far away are Battersea Park Lake and Henman Hill.