Greater London · England
Window Mastic in Keston
Mastic around window and door frames, sills and patio doors for Keston, backed by a one-year guarantee. Call for a quick quote.
- White mastic on grey or black frames
- Old mastic that has gone black or come away
- Rushed sealant from a window installation
What happens if it’s left?
If you are painting or rendering, reseal at the same time. Fresh joints finish the job neatly, and it’s easier while the walls are being worked on anyway. In a London flat, a failed joint rarely stays your problem alone: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether we need extra access for height. We take all of that into account in your quote.
Why book with us
- White, clear, grey or another colour, product permitting
- Any old sealant cut out fully, not covered over
- We leave the area clean and tidy
- We agree the colour with you first
Take a look at our cost guide and what customers say.
Window mastic in Keston, done properly
Colour matters on a frame. We can seal in white, brown, anthracite grey, black or clear, so the line suits the frame instead of standing out. We work on aluminium frames, uPVC windows and composite doors, and common reasons people get in touch are whistling draughts around closed windows and white mastic on grey or black frames.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. The mastic around them dries out and cracks with age, which is when draughts and damp patches appear in homes in Keston.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we’ll put it right.
- Place
- Keston (BR2)
- Region
- Greater London
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
When it isn’t the sealant
A few problems are outside what sealant work can do:
- A door that needs adjusting, rehanging or new seals
- Condensation trapped between the panes
- Faulty window hardware
If in doubt, call 0345 464 0079 or send us an email and we’ll say what we think before you book.
What we seal
- Timber windows & doors
- Composite doors
- uPVC windows
- Patio & French doors
- Aluminium frames
- Window sills
Places near Keston
Also in Keston
Looking after it afterwards
To keep the joints looking good and working properly:
- Clear any debris from frame drain holes
- Keep solvents and bleach off the sealant
- Wash the frames with mild soapy water
- Do not aim a pressure washer at the joints
Keep the new mastic undisturbed while it cures, following the cure time we give you. Keep jet washers away from the frames.
A small gap around a frame only grows. As old mastic keeps shrinking, the gap widens, and a cold room gets colder. Resealing closes it.
Signs you need window mastic in Keston
Frames are never completely still. A plastic or aluminium frame lengthens in sunshine and shortens as it cools, while the masonry beside it stays put. A sealant that can’t keep up eventually tears.
If you can see any of these, it’s time to have the joints looked at:
- Hard, cracked sealant around windows
- Mastic that is falling out in pieces
- White mastic on grey or black frames
- Cracked internal joints between frame and plaster
Homes close to Keston Parish Church include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Comparing quotes
- Which sealant they’ll use, and why
- When the joint can take water or movement
- Who does the work, and how experienced they are
- Is the old sealant removed completely?
FAQs for Keston
Do you work for landlords with property near Hayes (Kent) station?
Yes, landlords and agents are among the people we work for. You can ring 0345 464 0079 or drop us an email with the details for a clear quote.
Is Keston in your area for window mastic?
Yes. We work across London and the South East, and Keston is part of that. Just call 0345 464 0079 or drop us an email with a few details of the job, and we will send you a clear quote.
Will it make a mess?
Not at all. We work neatly, protect the area around the joints and tidy up afterwards.
Do you take out the old sealant first?
Yes, every time. New sealant will not bond properly to old, so any old material comes out before anything new goes in.
Is it OK to seal over old sealant?
No. Fresh sealant does not stick to old sealant, and anything trapped underneath, including mould and water, stays there. We remove it all first.
Should I try DIY first?
You can, for simple jobs. Preparation is everything: all the old sealant out, and a clean, dry joint. If it doesn’t work out, we can redo it.
Can new window sealant be painted?
It depends on the sealant. Some hybrid sealants can be painted; silicone can’t. Mention any painting plans before any work starts.
Will resealing my frames help with draughts?
Yes, if the air is getting in around the frame. If it’s through the window’s own seals or a hinge, that’s a different fix, and we will say so.
Should I try it myself first?
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Overfilling a joint is a classic DIY mistake. A heavy bead looks messy and copes badly with movement, and getting the depth right matters as much as the look.
Window mastic in Keston: local notes
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. Historic houses like Down House (about 2.2 miles south-east) are a reminder that the area around Keston has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
Keston is in London, so parking needs planning: let us know about parking bays, permits or a driveway. For site and facilities teams at buildings such as Keston Church of England Primary School, larger buildings have plenty of frames, and the mastic around each one ages.
Keston is about 3 miles south of Bromley, in Greater London. Wherever you are in the BR2 postcode area, our applicators can take on window mastic. Our area takes in 764 places across Greater London, from the larger towns to small villages. You can also see our page for London, about 11 miles away.
Jobs for window mastic in BR2 is quoted and booked the same way as anywhere else. If you need window mastic at a property on Church Road, Greys Park Close and Heathfield Road or anywhere close by, our applicators can take on the job. Neighbouring places we cover for window mastic include Nash (1 mile west), Farthing Street (1 mile south-east), Locksbottom (1 mile north-east), Leaves Green (2 miles south) and Hayes (2 miles north-west). Larger places within reach include London (11 miles north-west), City of Westminster (13 miles north-west), Marylebone (13 miles north-west), Kensington (14 miles north-west), St Pancras (13 miles north-west) and Shoreditch (12 miles north).
Local landmarks in Keston
In Keston, that means homes and buildings near South Park, Ravens Wood School and The Greyhound pub, among other places. The nearest railway station is Hayes (Kent) station, about 1.5 miles north-west of the centre. Other landmarks nearby include Princess Royal University Hospital (1.1 miles east) and Bethlem Museum of the Mind (1.5 miles north). Not far away are West Kent Golf Course nature reserve and Summer Hill.
What affects the cost of window mastic
We don’t publish a price list, because jobs vary so much. What we look at:
- Working hours on commercial sites
- How easy the joints are to reach
- The number and length of the joints
- Any mould that needs treating
What it costs depends on how much there is to do, how hard the old material is to remove and access to the work. You’ll have a clear quote before any work starts.
What to tell us for a quote
When you call or email, these details help:
- Where the property is
- Photos by email, if that’s easy
- Any previous sealing or DIY work
- Any access issues, like height or stairs
If you’re in Keston and need window mastic, phone 0345 464 0079 or drop us an email. Tell us what the problem is and where, and we’ll agree the price before any work begins.
The process
When we arrive, we start by going over the job with you, so there are no surprises. We protect the surfaces around the joints before we start. The work normally takes anything from an hour or two to a full day, depending on how many frames there are. In a London area like Keston, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we’re working on and whether there’s a lift.
- First, we confirm safe access to each frame.
- All the failed sealant is cut away, along with any loose debris.
- The surfaces are cleaned and left dry, and primed where the sealant calls for it.
- Deep voids are backed, then the sealant is gunned in.
- The joint is shaped to shed water and the area tidied.
Before we arrive
- Clear the area around the work
- Try not to wet indoor joints just before the visit
- Let us know if you’ve seen damp or leaks
Get a quote
Asking for a quote is easy: let us know what needs doing and where, and roughly how big it is. A few photos by email make the job easier to understand, and we will take it from there.