Greater London · England
Agar Town Window Mastic
Problem with your window and door frames in Agar Town? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- A bead that does not match the frame
- Draughts coming in around windows and doors
- Mastic that has split away from the wall
Window mastic in Agar Town
Most frames have an outside joint and an inside one. Outside, the mastic keeps rain out; the internal joint closes the gap to the plaster and stops draughts. We seal one or both, depending on what’s needed. We are often asked to deal with whistling draughts around closed windows and black, perished sealant on frames, across uPVC windows, composite doors and window sills.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease generally says who is responsible for the windows, so it’s worth checking before booking.
You get a one-year guarantee, the same in Agar Town as everywhere else we work.
- Place
- Agar Town (NW1W, NW1, N1)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What affects the cost of window mastic
Jobs vary more than people expect. What affects the quote:
- Mould in or behind the old joints
- How easy the joints are to reach
- How many areas need sealing
- Whether old sealant or filler has to be cut out
No two jobs are quite the same, so we quote each one individually. The number of joints, how easy they are to reach and the sealant needed all play a part, and we will explain the quote if you ask.
What to tell us for a quote
Photos help, but a description is a good start. Try to tell us:
- Where the job is, and your postcode
- What the problem is, such as mould, gaps, leaks or cracking
- Whether it has been sealed before
- Photos by email, if that is easy
Call for a quick quote, or send an email if you’d rather. Describe what needs sealing and we’ll talk you through the work and give you a clear quote.
Your questions about window mastic in Agar Town
Do you work for landlords with property near Camden Road station?
Yes, rental work is part of what we do. You can call 0345 464 0079 or email us with the address and a few details, and we will give you a fixed price before any work starts.
Can you do window mastic in Agar Town?
Yes. Our work covers London and the South East, and Agar Town is part of that. You can ring 0345 464 0079 or email us and let us know what needs doing.
Do you work on first-floor windows?
Yes, where they can be reached safely. Tell us about access when you get in touch so we can plan the job.
Is the work guaranteed?
Yes. Each job is covered for 12 months.
Can I paint over the new sealant?
It depends on the sealant. Silicone isn’t paintable, but some hybrid sealants are. Tell us if you are decorating and we’ll choose accordingly.
What do you need from me for a quote?
Where the job is, what the problem is and roughly how big it is. If you can, email a few pictures.
Can you seal over the old sealant?
No. New silicone will not bond to old silicone, and anything trapped underneath, including mould and water, stays there. We remove it all first.
Are you an approved applicator?
Yes. We hold ARBOMaster approved applicator status.
Why act early in Agar Town
Resealing frames is a short job: the visit takes anything from an hour or two to a full day, depending on how many frames there are. Wait for damp to appear and there may be plaster and decorating to sort out too. Converted houses in London often have a bathroom above someone else’s living room, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble.
Instead of a standard rate, we look at what your job involves: the amount of work, the old material and the access. You’ll know the price before we begin.
Why us?
- Every job guaranteed for a year
- We are fully insured
- White, clear, grey or another colour, product permitting
- You choose the colour before work begins
See our cost guide and our reviews.
Signs you need window mastic in Agar Town
Sills take more water than any other part of a window, so the sill ends and the joint below the frame are common leak points. When that sealant fails, water gets into the wall or under the frame.
Common reasons people contact us are:
- Black, perished sealant on frames
- Cracked internal joints between frame and plaster
- Whistling draughts around closed windows
- Hard, cracked sealant around windows
If you live in an older home near All Saints, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Before you book anyone
- Whether the sealant suits the joint
- Are they insured?
- What preparation is included
- What the cure time is
What the job involves on each surface
Composite doors
Front doors take the weather head on, and the top and bottom corners tend to fail first. Those corners get the most care.
Window sills
Masonry sills can have joints where water gets in, and the joint under the frame can let rain run behind. Those are sealed with a product suited to stone or concrete.
What we can’t put right
It helps to know what we can’t do too:
- Damp coming through the wall itself rather than the frame joint
- Rotten timber, which needs a joiner first
- Draughts through the window seals rather than the frame
Not sure which it is? You can ring 0345 464 0079 or drop us an email and we’ll tell you honestly before booking.
Surfaces we seal
- Window sills
- Aluminium frames
- Patio & French doors
- Composite doors
- Timber windows & doors
- uPVC windows
Window mastic in Agar Town: local notes
In a converted house or block, who looks after the windows depends on the lease, so check that before you book. With historic houses such as Winfield House (about 1.5 miles west) nearby, there’s older building stock in the area around Agar Town as well as newer homes. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
For landlords with property near Camden Road station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. Schools such as Abacus Belsize Primary School are buildings too, and its window and door frames need their mastic kept sound, just like a home’s.
Agar Town is about 1 mile north-west of St Pancras, in Greater London. Jobs in Agar Town get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. 764 places in Greater London are on our list, large and small.
Jobs for window mastic in NW1W, NW1 and N1 is quoted and booked the same way as anywhere else. Whether your property is on Water Lane, Maiden Lane and Camden Road or anywhere close by, we can help. Being close to the A400 and A5200, Agar Town is easy for our applicators to reach. Other places close to Agar Town include Camden Town (1 mile west), Somers Town (1 mile south), Kings Cross (1 mile south-east), Kentish Town (1 mile north-west) and Barnsbury (1 mile north-east). Larger places within reach include London (3 miles south-east), Kensington (4 miles south-west), Walthamstow (6 miles north-east), Whitechapel (3 miles south-east), Ruislip (12 miles west) and Brompton (3 miles south-west).
Near you in Agar Town
Typical jobs here are in homes near Vaughan Williams Memorial Library, Golden Lion pub and North Bridge House School. You’ll also find Regent High School (under half a mile south) and Lewis Cubitt Park (within half a mile east). There’s a railway station in Agar Town itself: Camden Road station. Other landmarks nearby include St Pancras Hospital (within half a mile south) and Montfichet's Tower (2.2 miles south-east). For a walk, there’s Barnsbury Wood and St. James's Park Lake.
How to look after the new joints
How long the joints last depends on use and care. We suggest:
- Air rooms to keep condensation down around windows
- Avoid harsh chemicals near the mastic
- Repaint timber before it’s bare
- Look round the frames every year or so
Wipe the frames with soapy water when you clean the windows, and avoid solvent cleaners on the sealant.
A failed joint lets water into the wall a little at a time. You might not see it until plaster blows or a damp patch appears inside. Early resealing stops it reaching that point.
What we do, step by step
A visit follows a simple pattern: we look at the joints together, protect the area around them, carry out the job and tidy away. It normally takes a few hours for a few frames, or a day or more for a whole house. For a job in Agar Town, parking and access are the things to plan: let us know about parking, the floor we will be working on and any lift or shared entrance.
- First we look at every frame and agree the list.
- 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.
- Finally we tidy up and check each joint.
Preparing for the visit
- Move anything stored near the joints
- Tell us about access, such as stairs, a lift or high-level joints
- Tell us if parking is tricky
How to get a quote
The more we know about the job, the more useful the quote. Tell us where the job is, what’s wrong and how much there is, and email photos if that is easy.