Greater London · England
Window & door mastic in Mildmay, Greater London
Window and door frames in Mildmay need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Mastic that has split away from the wall
- Damp patches on the reveal after heavy rain
- Whistling draughts around closed windows
Mildmay questions
I let a flat near Dalston Kingsland station. Can you help?
Yes. We work for landlords and agents as well as homeowners. You can phone 0345 464 0079 or email us with the details for a clear quote.
Can parking be tricky for a visit in Mildmay?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. That way the visit can be planned around it.
Do I have to be there?
We need access to the joints, so we’ll agree that with you when we book. For inside work, that normally means someone being in.
Can new window sealant be painted?
Not generally, if it’s silicone. Tell us your decorating plans and we’ll pick a sealant to suit.
Will new mastic stop draughts?
It will if the frame joint is the problem. We check where the draught is before work begins.
Is it OK to seal over old sealant?
No, and we never do. It may look fine at first, but the new bead soon lifts. Removing the old sealant completely is the only lasting way.
Do you come to Mildmay?
We do. Our applicators work in Mildmay, and the service is the same as everywhere else.
Are you an approved applicator?
Yes. Mr Mastic is an ARBOMaster approved applicator.
Window mastic in Mildmay
A cold draught around a closed window often comes from the frame edge. A new joint stops the air getting through. Where the air is getting in through the window itself, we’ll say so. We are often asked to deal with gaps left after new windows were fitted and old mastic that has gone black or come away, across window sills, aluminium frames and patio & French doors.
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 Mildmay.
Each job carries a 12-month guarantee, whatever its size.
- Location
- Mildmay (N1, N16, E8)
- Region
- Greater London
- Cover
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Different surfaces, different methods
Patio & French doors
The joints around patio doors run a long way, top, sides and threshold. The threshold and the bottom corners take the most water, so we pay close attention there.
uPVC windows
Plastic frames move a lot between a hot afternoon and a cold night, so we use a flexible, low-modulus sealant. White is the usual colour, with brown, anthracite grey and black for coloured frames.
How it works
You don’t need to clear the whole room or building before we come, only the area right around the joints. We protect the rest, and the work takes a morning for a couple of windows and a door in most cases. In Mildmay, as in most of London, parking needs a little planning. A visitor permit or a nearby bay makes the visit run more smoothly.
- Each frame is looked over and we agree which ones need resealing.
- We remove the old mastic and clean the frame edge and wall.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
Getting ready for the visit
- Mention any sign-in or site rules at work premises
- Let us know if you’ve seen damp or leaks
- Keep pets and children clear of the area while we work
Ask for a quote
Need a quote? Please phone 0345 464 0079 or email us with a few details. You will know what we plan to do, and what it will cost, before any work begins.
Read more
DIY versus a professional finish
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Places near Mildmay
Other services in Mildmay
Mildmay homes and the weather
In a converted house or block, who looks after the windows depends on the lease, so check that before you book. Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Homes close to Church of St Jude and St Paul include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall. If you let a flat or house near Dalston Kingsland station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first.
Mildmay is about 1 mile north of Hoxton, in Greater London. Anywhere in N1, we cover window mastic for homes and businesses. Mildmay is one of 764 places in Greater London where we work for window mastic.
We cover every part of the N1, N16 and E8 postcode area for window mastic. If you need window mastic at a property on Dove Road, Essex Road and Burma Road or anywhere close by, our applicators can take on the job. Mildmay sits on or near the A1199. We also cover the places around Mildmay: Newington Green (1 mile north), De Beauvoir Town (1 mile south), Canonbury (1 mile south-west), Kingsland (1 mile south-east) and Highbury (1 mile west). Within a short drive, we also cover London (3 miles south), City of Westminster (4 miles south-west), Marylebone (3 miles south-west), Kensington (6 miles south-west), Walthamstow (4 miles north-east) and Hampstead (4 miles west).
Near you in Mildmay
We work in homes and buildings around City of London Academy Highbury Grove, Highbury Fields and Army and Navy pub and the streets around them. Mildmay has its own railway station: Dalston Kingsland station. Well-known places in the area include Clowns Gallery-Museum (0.6 miles south-east) and Hackney Walk (1.5 miles east). Green spaces nearby include Gillespie Park and Ludgate Hill.
What happens if it’s left?
Running fresh sealant over the old joint is tempting, but it won’t grip old, dirty sealant. It peels before long, and water still gets in behind. Proper resealing starts with removing the old joint. 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 Mildmay, the repair is bigger than the sealant job would have been.
There are no prices on our website, because the cost depends so much on the job itself. Call for a quick quote and we will talk you through it.
Why Mildmay clients choose us
- Arbo and Everbuild products
- Full insurance on every job
- You choose the colour before work begins
- Every job guaranteed for a year
Read what affects the cost or customer reviews.
When it is not the sealant
To be straight with you, some problems need a different trade:
- A sash or casement that won’t close properly
- A door that needs adjusting, rehanging or new seals
- Damp coming through the wall itself rather than the frame joint
If you’re not sure, just call 0345 464 0079 or email us and we’ll give you a straight answer.
Joints and surfaces we work on
- Aluminium frames
- Composite doors
- Patio & French doors
- uPVC windows
- Window sills
- Timber windows & doors
For landlords and businesses
Mouldy or split sealant often shows up at the end of a tenancy, and it’s quick to put right between tenancies. Several properties can go on one quote.
A neglected joint can let water reach the structure, which is a bigger problem in a rented property. Resealing at the right time is simple maintenance that we can handle for you.
Common problems we fix in Mildmay
Frames are never completely still. Sun on a frame makes it expand, and it contracts again overnight, while the masonry beside it stays put. If the sealant cannot stretch, it splits.
These are the problems we are asked about most:
- Black, perished sealant on frames
- Mastic that has split away from the wall
- Cracked sealant at the sill ends
- Cold air getting in at the frame edge
Schools such as Newington Green Primary School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
What your quote should include
- The length of the guarantee
- Who does the work, and how experienced they are
- What preparation is included
- How long to leave it before use