Greater London · England
Window Mastic in Chelsea
Window mastic in Chelsea from a team with over 20 years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Old mastic that has gone black or come away
- Water coming in at the bottom corners of a door
- Hard, cracked sealant around windows
Common problems we fix in Chelsea
Some failures date back to when the windows were fitted. Sealant run over dust, wet brick or loose mortar never bonded as it should, so it comes away long before its time.
Keep an eye out for these signs:
- Damp patches on the reveal after heavy rain
- Cracked or shrunken mastic around the frame
- Untidy mastic left by window fitters
- Cracked sealant at the sill ends
If you look after a building such as Oratory Roman Catholic Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Comparing quotes
- What product goes in the joint
- What happens if the job turns out different
- What guarantee comes with the work
- Which colour the sealant will be
Window mastic in Chelsea
The mastic around a window or door seals the gap between the frame and the wall. Once that seal fails, wind and rain find the gap. Our applicators cut it out and replace it with a flexible, weatherproof sealant. We’re often asked to deal with gaps between the frame and the inside reveal and gaps where the sill meets the wall, across timber windows & doors, composite doors and aluminium frames.
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, and access in Chelsea is something to talk through when you book.
You are covered for a year from the day we finish. If there’s a problem with it, please phone 0345 464 0079 or email us.
- Where
- Chelsea (SW3, SW10, SW1X, SW1W)
- Region
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear price before work begins
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
How to look after the new joints
Joint life depends on how it’s used and looked after. Here’s what we suggest:
- Keep solvents and bleach off the sealant
- Paint up to the joint, not over it
- Wash the frames with mild soapy water
- Clear any debris from frame drain holes
On timber frames, keep the paintwork in good order, since wood that gets wet swells and shrinks more. Keep paint off the silicone itself.
Look out for the warning signs: cracks in the mastic, gaps you can see light through, damp on the reveal or mould around the inside of the frame. If you notice one, it’s time to get the joint looked at.
Nearby places to Chelsea
What else we do in Chelsea
What window mastic looks like in Chelsea
In London conversions and blocks, the lease decides who is responsible for the frames, so check that before you book. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Homes close to Former Welsh Congregational Church include some older properties, and the joint between an old wall and a newer frame is normally the first place rain gets in. As a London address, Chelsea can be tricky for parking: let us know about parking bays, permits or a driveway.
Chelsea is about 2 miles south-east of Kensington, in Greater London. Homes, rented property, offices and hotels in Chelsea can book us for window mastic. The work is guaranteed for a year. Across Greater London, we cover 764 places, Chelsea among them.
Here we cover the SW3, SW10, SW1X and SW1W postcode area for window mastic. If you need window mastic at a property on Markham Square, Wellington Square and Tedworth Square or a nearby road, our applicators can take on the job. With the B302 and B304 close by, Chelsea is easy for our applicators to reach. If you’re just outside Chelsea, we cover Brompton (1 mile north), South Kensington (1 mile west), Little Chelsea (1 mile south-west), Belgravia (1 mile north-east) and World's End (1 mile south-west). Within a short drive, we also cover London (3 miles east), St Pancras (3 miles north-east), Shoreditch (5 miles north-east), Walthamstow (9 miles north-east), Hoxton (5 miles north-east) and Whitechapel (5 miles north-east).
Landmarks near Chelsea
In Chelsea, that means homes and buildings near Burton’s Court, St Thomas More RC Language College and Markham Arms Public House. You will also find Natural History Museum Library and Archives (0.7 miles north-west) and Hellenic College of London (0.5 miles north). The nearest railway station is London Victoria station, roughly 1 mile north-east. A little further out are Baynard's Castle (3.2 miles north-east) and Harrods (0.7 miles north). Green spaces nearby include Campden Hill and Battersea Park Lake.
The process
The work is kept neat and contained to the area we’re working on, so you can get on with your day. The job normally takes a few hours for a few frames, or a day or more for a whole house, and we tell you how long to leave it before we go. In Chelsea, 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 start by checking each window and door with you.
- Next the failed sealant is cut away and the joint cleaned.
- Deep gaps are filled with backing rod to set the depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Finally we tidy up and check each joint.
How to prepare
- Let us know about stairs, lifts or work at height
- Mention if the joints have been sealed before
- Let us know about parking restrictions
Getting a quote
Need a quote? Please ring 0345 464 0079 or email us with a few details. We will explain what we’d do and give you a clear price before any work starts.
Advice
What we cannot put right
It helps to know what we cannot do:
- A door that needs adjusting, rehanging or new seals
- A failed sealed unit that has misted up
- Faulty window hardware
If you’re not sure, just phone 0345 464 0079 or email us and we’ll give you a straight answer before booking.
Where we work in Chelsea
- Window sills
- Timber windows & doors
- Patio & French doors
- uPVC windows
- Composite doors
- Aluminium frames
Can I do it myself?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
If you are set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it fails, we can still redo it.
Leave it or put it right?
Getting a straight, even bead on an outside frame takes practice, especially on upper floors. We cut out properly, back deep gaps and tool every joint neatly, in a sealant suited to the wall. In London conversions, one flat’s bathroom is often above another flat’s ceiling, and a slow leak from a failed seal can end up in the flat below. Dealing with it early is far simpler.
The cost reflects the work involved, not a rough estimate. That is why we ask about the job first and send you a clear quote before any work starts.
Why book with us
- A sealant colour to suit the surroundings
- Tidy, careful work
- A 12-month guarantee on all work
- Sanitary silicone with an anti-fungal additive in wet areas
Read what affects the cost and our reviews.
Landlords, agents and businesses in Chelsea
For anyone letting property in or around Chelsea, several properties can be quoted together. Send us the addresses and the work at each.
We regularly work with letting and managing agents. Send the address, what’s needed and the access arrangements and we will quote.
Your questions about window mastic in Chelsea
Can parking be tricky for a visit in Chelsea?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Do you cover Chelsea for window mastic?
Yes. Our work covers London and the South East, and Chelsea is part of that. Just phone 0345 464 0079 or send us an email with a few details of the job.
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.
Can you seal over the old sealant?
No. The old sealant always comes out first, so the new joint bonds to clean surfaces.
Does the work come with a guarantee?
Yes. Our one-year guarantee covers every job, inside or out.
Can you match the sealant to my frames?
Yes. We can use white, brown, anthracite grey, black or clear.
How long will my window job take?
It depends on access, the old mastic and the size of the frames. You’ll know the timing when we quote.
Which products do you use?
Products from Arbo and Everbuild, among others, picked for each joint. We will tell you what we’re using and why.