Greater London · England
Eltham Window Mastic
We cover Eltham for mastic around window and door frames, sills and patio doors. Old sealant removed completely, joints prepared properly.
- Gaps left after new windows were fitted
- Hard, cracked sealant around windows
- Water coming in at the bottom corners of a door
Window mastic for homes and businesses in Eltham
Some gaps around frames are far deeper than they look. Filling it with sealant alone leaves a joint that cannot move properly, so deep gaps get backing rod first. That way the new bead bonds to the frame and the wall only. If you have gaps left after new windows were fitted and draughty joints inside around the window, we can help.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. Over the years, the sealant around them shrinks, cracks and pulls away, letting in draughts and water.
Our work is backed for twelve months.
- Place
- Eltham (SE9, SE12, DA15, BR7)
- Region
- Greater London
- Cover
- One year on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
What we can’t put right
Honest advice matters more to us than a booking, so here’s what sealant cannot fix:
- Worn gaskets, brush seals or a door that has dropped
- A sash or casement that won’t close properly
- Misting between the panes of a double-glazed unit (that needs a new unit)
Not sure which it is? You can phone 0345 464 0079 or send us an email and we’ll tell you honestly.
What we seal
- Aluminium frames
- Window sills
- Composite doors
- Timber windows & doors
- Patio & French doors
- uPVC windows
More services for Eltham
Questions from Eltham
Can you do window mastic in Eltham?
Yes, Eltham is within the area we cover. Our work covers London and the South East. Just phone 0345 464 0079 or send us an email with a few details of the job, and we’ll give you a clear quote.
Can you help a landlord with a rental near Mottingham station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. Just ring 0345 464 0079 or email us with the address and what needs doing, and we will send you a clear quote.
Do the sealants smell?
It depends on the product. Some smell for a while, some hardly at all, and any smell fades as they cure.
What does window mastic cost?
There’s no set price, as it depends on the job: how much there is, what’s there now, how we reach it and what it needs. You will get a clear quote before work begins.
What sealant do you use?
We choose the sealant for the joint, not the other way round. Movement, water and weather all affect the choice.
Can you seal over the old sealant?
No, because it fails. We remove every bit of old sealant first, so the new joint bonds to clean surfaces.
Will resealing my frames help with draughts?
Yes, where the draught is at the frame edge. We find where the air is coming from before we reseal.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status, and we’re fully insured.
How the job changes by surface
Timber windows & doors
Soft or rotten wood can’t be sealed successfully. If we find rot, we’ll tell you before going ahead, as that’s a job for a joiner.
uPVC windows
We clean the frame edge carefully so the plastic is not marked, then the new bead is laid against the frame and the wall and tooled smooth.
Why act early in Eltham
Getting a straight, even bead on an outside frame takes practice, especially upstairs. We cut out properly, back deep gaps and tool every joint neatly, using a product chosen for the frame and wall. 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 Eltham, 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, how we reach it and what it needs. Ask us for a quote and we’ll go through it with you.
Why us?
- White, clear, grey or another colour, product permitting
- Trusted Arbo and Everbuild sealants
- We agree the colour with you first
- Anti-fungal sanitary silicone in wet areas
Signs you need window mastic in Eltham
Sills take more water than any other part of a window, and the ends of the sill, where it meets the wall, are where it gets in. When that sealant fails, water gets into the wall or under the frame.
These are the problems we’re asked about most:
- Gaps left after new windows were fitted
- Cracked sealant at the sill ends
- Rain getting in at the frame or under the sill
- Draughts coming in around windows and doors
Schools such as St Thomas More Catholic Comprehensive School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
What your quote should include
- Whether you can choose the colour
- Whether the sealant suits the joint
- Whether they’re fully insured
- Who does the work, and how experienced they are
What window mastic looks like in Eltham
Historic houses like Eltham Palace (about 0.4 miles north-west) are a reminder that the area around Eltham has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.
As a London address, Eltham can be tricky for parking: let us know about parking bays, permits or a driveway. For an older house near a landmark such as Church of Holy Trinity, the joint between an old wall and a newer frame is generally the first place rain gets in.
Eltham is about 7 miles west of Dartford, in Greater London. Wherever you are in the SE9 postcode area, we can carry out window mastic at your property. 764 places in Greater London are on our list. For nearby work, see our London page.
Here we cover the SE9, SE12, DA15 and BR7 postcode area for window mastic. Streets in the area include Eltham High Street, Tarnwood Park and Elmslie Court, and we cover them all. Main roads around Eltham include the A20 and B263. Neighbouring places we cover for window mastic include Middle Park (1 mile west), New Eltham (1 mile south-east), Well Hall (1 mile north), Coldharbour (1 mile south) and Avery Hill (1 mile north-east). Further out, we also cover London (8 miles north-west), City of Westminster (10 miles north-west), Marylebone (10 miles north-west), Kensington (12 miles west), St Pancras (9 miles north-west) and Shoreditch (8 miles north-west).
Local landmarks in Eltham
Locally, jobs take us to homes and businesses close to Horn Park, Eltham Church of England Primary School and The Greyhound Public House and the streets around them. There’s a railway station in Eltham itself: Mottingham station. A little further out are Eltham Community Hospital (under half a mile north) and Metropolitan Police Museum (2.1 miles east). The countryside around Eltham includes The Tarn and Summer Hill.
What happens on the day
At the end, we look at the finished work together and tell you how long to leave it. The visit itself usually takes most of a day for a typical house, less for a few frames, depending on the amount of work. For a job in Eltham, parking and access are the things to plan: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- We start by checking each window and door with you.
- Next the failed sealant is cut away and the joint cleaned.
- We fit backing rod in deep gaps so the sealant is the right depth.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- Every joint is checked before we leave.
Before we arrive
- Keep pets and children clear of the area while we work
- Where the joints are inside, avoid wetting them before we arrive
- Clear items away from the joints we’re working on
Ask for a quote
Call for a quick quote, or email us if that is easier. Describe what needs sealing and we’ll talk you through the work.
Related advice
How we quote for window mastic
There’s no set price list, because no two jobs are the same. The quote depends on:
- Any working-time requirements on site
- How many rooms, windows or areas are involved
- Any mould that needs treating
- The size of the job
Rather than a set price list, we price the job in front of us: how many joints, what’s in them now and how we reach them. You’ll know the price before we begin.
Asking for a quote
To help us quote quickly, let us know:
- Whether it has been sealed before
- Whether it’s a home or a business
- Where the job is, and your postcode
- What’s wrong with the joints now
We quote each job on its own. Just ring 0345 464 0079 or email us with the details and send pictures if you have them.
Work for landlords, hotels and businesses
Failed sealant is one of the commonest items on a check-out report, and it’s quick to put right between tenancies. Several properties can go on one quote.
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Resealing at the right time is simple maintenance that we can handle for you.