Greater London · England
Hendon Window Mastic
Professional window mastic in and around Hendon, with old sealant always removed completely and a 12-month guarantee.
- Leaking joints at the ends of sills
- Cracked internal joints between frame and plaster
- Hard, cracked sealant around windows
Common problems we fix in Hendon
Mastic ages in the weather. Sunlight dries the surface out, and over the years it loses its give, cracks and comes away.
Signs it’s time to call us include:
- Draughts coming in around windows and doors
- Sealant in the wrong colour for the frame
- Hard, cracked sealant around windows
- Gaps between the frame and the inside reveal
Managing a site like Hendon School? Then the mastic around its windows and doors needs looking after like any other building’s.
What your quote should include
- What product goes in the joint
- Whether VAT is included
- How the colour is chosen
- What happens if the job turns out different
Window mastic in Hendon
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 composite doors, window sills and timber windows & doors, and the jobs we see most are untidy mastic left by window fitters and cracked internal joints between frame and plaster.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Either way, the mastic between frame and brickwork is what stops draughts and rain getting in, in Hendon as anywhere.
A one-year guarantee comes as standard, so you are not left on your own once the job is done.
- Location
- Hendon (NW4, NW9, NW2, NW11)
- Region
- Greater London
- Cover
- One year on every job
- Price
- A clear price before work begins
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
What happens if it’s left?
The work is quick compared with the damage it prevents: it takes most of a day for a typical house, less for a few frames. Wait for damp to appear and there may be plaster and decorating to sort out too. In a London flat, a failed joint rarely stays your problem alone: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
Leaving a failed joint usually makes the job bigger, not smaller. If you’re not sure whether it needs doing, call 0345 464 0079 or send us an email and we’ll give you an honest view and a quote.
What you get with us
- We agree the colour with you first
- A 12-month guarantee on all work
- Old sealant always removed completely
- Anti-fungal sanitary silicone in wet areas
Take a look at our cost guide and what customers say.
Towns and villages near Hendon
What else we do in Hendon
Frames and glazing around Hendon
Historic houses like Heath Hall (about 2.3 miles east) are a reminder that the area around Hendon 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. Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Rented homes near Hendon station change hands often, and sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. In the older streets around Christ Church Hendon, the joint between an old wall and a newer frame is normally the first place rain gets in.
Hendon is about 3 miles north-west of Hampstead, in Greater London. For window mastic in and around Hendon, it’s easy to get a quote: please phone 0345 464 0079 or email us. We cover Greater London from our Crawley base. Our Greater London coverage runs to 764 places, Hendon among them. Our London page covers work nearby.
Here we cover the NW4, NW9, NW2 and NW11 postcode area for window mastic. Local streets include Church Road, Station Road and Sydney Grove, and we cover them all. Being close to the A5 and A41, Hendon is simple for us to get to. Other places close to Hendon include The Burroughs (1 mile north-west), Brent Cross (1 mile south), Staples Corner (1 mile south), West Hendon (1 mile west) and The Hyde (1 mile west). Further out, we also cover London (8 miles south-east), City of Westminster (6 miles south-east), Marylebone (6 miles south-east), Kensington (6 miles south), St Pancras (6 miles south-east) and Shoreditch (7 miles south-east).
Local landmarks in Hendon
Locally, jobs take us to homes and businesses close to Hasmonean Primary School, The White Bear pub and Kisharon College. The nearest railway station is Hendon station, roughly 0.7 miles south-west of the centre. Nearby you will also find Brent Cross Shopping Centre (0.5 miles south) and St Andrew's Hospital (1.6 miles south). For a walk, there’s Darland's Lake and Parliament Hill.
The process
The work is kept neat and contained to the joints we’re treating. The job usually takes a few hours for a handful of frames, longer for a whole house. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Hendon. A visitor permit or a nearby bay makes the visit run more smoothly.
- We start by checking each window and door with you.
- The old mastic is cut out and the surfaces cleaned back.
- Deep gaps are filled with backing rod to set the depth.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- We clear up and check every joint is fully closed.
Before we arrive
- Keep pets and children clear of the area while we work
- Clear items away from the joints we’re working on
- Tell us about any water getting in
Getting a quote
To get a quote, phone 0345 464 0079 or email us and tell us where the job is and what the problem looks like. We’ll give you a clear quote before any work starts.
Advice
Work for landlords, hotels and businesses
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. We can quote for more than one property at once.
We also work for property managers and facilities teams. We can quote a run of properties together, and we are fully insured for the work.
Aftercare tips
Simple care keeps the joints in good condition. Our advice:
- Look round the frames every year or so
- Do not aim a pressure washer at the joints
- Do not use solvent cleaners on the joint
- Make sure the drainage slots are not blocked
Silicone can’t usually be painted, so if you are planning to paint the frames or walls, tell us beforehand. We can use a paintable sealant where that matters.
On timber windows, water behind the joint can lead to rot. Once wood has rotted, it needs repair before it can be sealed, so early resealing is worth it.
Hendon questions
Can you do window mastic in Hendon?
Yes, Hendon is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or drop us an email with a few details of the job.
Is parking an issue for window mastic in Hendon?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. That way the visit can be planned around it.
Can I do it myself?
Some simple jobs can be done by a careful DIYer. The usual mistakes are sealing over old sealant, sealing a damp joint and using too much.
Can landlords and businesses book you?
Yes, regularly. Several properties can be quoted together.
How long will my window job take?
It depends on access, the old mastic and the size of the frames. We will tell you how long your job needs when we quote.
What do you need from me for a quote?
Just the basics: where it is, what you’ve noticed and how we reach it. After that, simply ring 0345 464 0079 or send us an email.
How long before the joint can be used?
That depends on the sealant used, so follow the cure time we give you.
Can I paint over the new sealant?
Most silicone can’t be painted. Let us know beforehand, and we will use a paintable product where it suits.
DIY sealant or a professional job?
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
Quotes for window mastic in Hendon
We quote each job individually. This is what makes a difference:
- Which sealant suits the joint
- The size of the job
- How many areas need sealing
- Working hours on commercial sites
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed, along with when we can work on site. Ask us for a quote and we’ll explain what it covers.
What to tell us for a quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- The type of property
- Photos by email, if that is easy
- Whether it has been sealed before
- Access, such as stairs, a lift or height
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is.