City of London · England
Window & door mastic in City of London
Window mastic in City of London from a team with over 20 years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Whistling draughts around closed windows
- Cracked sealant at the sill ends
- Old mastic that has gone black or come away
Window mastic in City of London, done properly
Frames and walls do not move together. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. So the sealant has to stretch and recover, which is why we use a low-modulus product. Common call-outs are for sealant in the wrong colour for the frame and cold air getting in at the frame edge, on window sills, aluminium frames and composite doors.
Many London homes are flats, with windows high above the street. In a converted house or block, the lease generally says who is responsible for the windows, so it’s worth checking before booking.
There’s a 12-month guarantee on every job.
- Place
- City of London (EC4V, EC1A, EC2M, EC2Y)
- Region
- City of London
- Cover
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Common questions in City of London
Can you help a landlord with a rental near London Cannon Street station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we’ll give you a clear price.
Can parking be tricky for a visit in City of London?
In much of London, parking needs planning: a visitor permit or a bay close to the door helps a lot, so mention what’s available when you book.
Is the work guaranteed?
Yes. All our work carries a 12-month guarantee, and we’re ARBOMaster approved applicators.
Can I paint over the new sealant?
Not normally, if it’s silicone. We choose the product with your decorating in mind, so mention it when you book.
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.
How long will my window job take?
A few frames take a few hours. You’ll get a timescale with the quote.
Do you do commercial work?
Yes. We can plan bigger jobs in stages to suit the site.
Can new sealant go over the old?
No, it will not last. It may look fine at first, but the new bead soon lifts. Removing the old sealant completely is the only lasting way.
Places near City of London
What else we do in City of London
Aftercare tips
So the new joints stay in good condition:
- Keep paint off silicone joints
- Don’t aim a pressure washer at the joints
- Check the mastic once a year
- Make sure the drainage slots aren’t blocked
Wipe the frames with soapy water when you clean the windows, and avoid solvent cleaners on the sealant.
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.
Why act early in City of London
A cracked joint around a frame lets rain into the wall. Over time that can mean damp patches, damaged plaster and rotting timber. A reseal is a much smaller job. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in City of London, the repair is bigger than a sealant job.
There are no prices on our website, because each job is priced on what it involves. For a quick quote, please ring 0345 464 0079 or email us.
Why book with us
- A 12-month guarantee on all work
- Fully insured
- Sanitary silicone with an anti-fungal additive in wet areas
- Quality sealants from Arbo and Everbuild
See our cost guide or customer reviews.
How the visit works
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 any work begins. The work normally takes a morning for a couple of windows and a door. For a job in City of London, 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.
- Each frame is looked over and we agree which ones need resealing.
- The old mastic is cut out and scraped back to clean surfaces.
- Where the gap is deep, backing rod goes in first.
- The new sealant goes on in white, brown, anthracite grey, black or clear to suit.
- We tool each bead neatly and check every joint is closed.
Getting ready for the visit
- Let us know about earlier repairs to the joints
- Tell us about access, such as stairs, a lift or high-level joints
- Try not to wet indoor joints just before the visit
How to get a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and email photos if that’s easy.
Related advice
Window mastic in City of London: local notes
With historic houses such as Mansion House (about 0.2 miles south-east) nearby, there’s older building stock in the area around City of London as well as newer homes. 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.
If you let a flat or house near London Cannon Street station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. In the older streets around St Olave Old Jewry, the joint between an old wall and a newer frame is normally the first place rain gets in.
City of London is about 1 mile north of London, in City of London. From the centre of City of London to the outskirts, we cover window mastic for every kind of property.
Postcode districts we cover here for window mastic: EC4V, EC1A, EC2M and EC2Y. You will find streets such as Aldermanbury Square, Monkwell Square and Paternoster Square. With the A1 and A3 close by, City of London is simple for us to get to for window mastic. Other places close to City of London include Barbican Estate (1 mile north), Bishopsgate (1 mile east), Finsbury (1 mile north), Aldgate (1 mile east) and St Luke's (1 mile north).
Near you in City of London
Locally, jobs take us to homes and businesses close to St Mary-at-Hill, Prior Weston Primary School and Children's Centre and Golden Fleece pub, among other places. Nearby too are Central Foundation Boys' School (0.8 miles north), Barts Health Archives (less than half a mile north-west) and St Alphage Garden (under half a mile north). City of London has its own railway station: London Cannon Street station. Well-known places in the area include Gabriel's Wharf (0.8 miles south-west) and London Mithraeum (under half a mile south). Green spaces nearby include St. James's Park Lake and Barnsbury Wood.
What we can’t put right
Some problems need a builder, plumber or other trade rather than us:
- Damp coming through the wall itself rather than the frame joint
- A door that needs adjusting, rehanging or new seals
- Faulty window hardware
If you’re not sure, just phone 0345 464 0079 or drop us an email and we’ll give you a straight answer before you book.
Joints and surfaces we work on
- uPVC windows
- Patio & French doors
- Window sills
- Aluminium frames
- Timber windows & doors
- Composite doors
Work for landlords, hotels and businesses
Water getting past a failed joint can damage the building, which matters even more when someone else lives there. Keeping joints in good order is simple maintenance that we can handle for you.
For anyone letting property in or around City of London, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and pictures by email help.
What we are called out for in City of London
A lot of older mastic was never designed to stay flexible. Once it has hardened, the frame’s movement tears it from the wall, and a gap opens along one edge.
Signs it’s time to call us include:
- Rain getting in at the frame or under the sill
- Black, perished sealant on frames
- Gaps where the sill meets the wall
- Draughty joints inside around the window
If you look after a building such as Fashion Retail Academy, larger buildings have plenty of frames, and the mastic around each one ages.
What your quote should include
- Are they insured?
- Who does the work, and how experienced they are
- The length of the guarantee
- Which sealant they’ll use, and why
What the job involves on each surface
Timber windows & doors
Older timber windows in stone or brick can suit sand mastic rather than modern sealant. We’ll tell you which suits your home.
Aluminium frames
Aluminium needs a sealant that bonds to coated metal, and acetoxy silicones are not used, as they can attack some metals. We use a neutral-cure product.