Greater London · England
Seven Sisters Window Mastic
Window mastic for Seven Sisters, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Water coming in at the bottom corners of a door
- Mastic that is falling out in pieces
- Whistling draughts around closed windows
How we handle window mastic in Seven Sisters
Mr Mastic’s applicators have more than 20 years’ experience with window and door sealants. We are fully insured ARBOMaster approved applicators, and we give a 12-month guarantee on the work. If you are dealing with cracked internal joints between frame and plaster and sealant in the wrong colour for the frame, we can put it right, on composite doors, uPVC windows and aluminium frames alike.
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, letting in draughts and water.
Each job carries a 12-month guarantee, whatever its size.
- Where
- Seven Sisters (N15, N17, N16)
- Region
- Greater London
- Guarantee
- One year on every job
- Quote
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Questions from Seven Sisters
Do you work for landlords with property near Seven Sisters station?
Yes, landlords and agents are among the people we work for, and several properties can go on one quote. You can call 0345 464 0079 or drop us an email with the details for a clear quote.
Is parking a problem for a job in Seven Sisters?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly, so mention what’s available when you book.
Are you fully insured?
Yes, we are fully insured for domestic and commercial work.
When is the sealant fully cured?
It depends on the product and the conditions. Before we leave, we will tell you the cure time.
Can you seal over the old sealant?
No, and we never do. It can look neat for a few weeks, but the new bead soon lifts. Removing the old sealant completely is the only lasting way.
Will the old sealant be removed?
Yes, always, and completely. New silicone does not stick to old silicone, so the joint is cleaned back first.
What should I tell you?
Only a few details: where it is, what you’ve noticed and how we reach it. After that, simply phone 0345 464 0079 or email us.
Do you have sealant for grey or black windows?
Yes. White, brown, anthracite grey, black and clear sealants are all available.
Surface by surface
Composite doors
Composite doors are normally hung in an uPVC-type frame, so its perimeter joint is sealed much like a window. The bead is colour-matched to the frame.
Patio & French doors
Not every patio door leak is a mastic problem: blocked drain slots, worn brush seals and threshold details can let water in too. We look for the cause first.
Nearby places to Seven Sisters
What else we do in Seven Sisters
How it works
The work is kept neat and contained to the area we’re working on. The job usually takes a few hours for a few frames, or a day or more for a whole house, and we tell you how long to leave it before we go. In a London area like Seven Sisters, the main things to plan are parking and access: let us know about parking, the floor we’ll be working on and any lift or shared entrance.
- We start by checking each window and door with you.
- The old mastic is cut out and the surfaces cleaned back.
- Where gaps are deep, backing rod goes in first.
- 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
- Keep pets and children clear of the area while we work
- Where the joints are inside, avoid wetting them before we arrive
- Let us know about parking restrictions
Ask for 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.
Read more
Quotes for window mastic in Seven Sisters
You’ll get a clear quote before work begins. It’s based on:
- When we can work, for business premises
- How many areas need sealing
- The number and length of the joints
- The type of sealant required
The cost reflects the work involved, not guesswork. That’s why we ask about the job first.
What to tell us for a quote
Photos by email are helpful but not essential. Try to tell us:
- What’s wrong with the joints now
- Any previous sealing or DIY work
- Photos by email, if that is easy
- How many joints, rooms or windows are involved
To get a quote, call 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. We will give you a clear price before any work starts.
Seven Sisters homes and the weather
With historic houses such as Bruce Castle (about 1.2 miles north) nearby, there’s older building stock in the area around Seven Sisters as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window. In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking.
Managing a site like Earlsmead Primary School? Then larger buildings have plenty of frames, and the mastic around each one ages. For an older house near a landmark such as Church of Holy Trinity, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Seven Sisters is about 2 miles west of Walthamstow, in Greater London. Every kind of property in Seven Sisters is covered for window mastic, old or new, large or small. Every job comes with our one-year guarantee. Our Greater London coverage runs to 764 places, Seven Sisters among them. There’s also a page for London, roughly 6 miles from Seven Sisters.
Our applicators cover all of the N15, N17 and N16 postcode area for window mastic and the streets around it. Local streets include Ida Road, Elmar Road and Grove Road. Neighbouring places we cover for window mastic include South Tottenham (1 mile north), Tottenham Green (1 mile north), St Ann's (1 mile west), Tottenham Hale (1 mile north-east) and West Green (1 mile west). Further out, we also cover London (6 miles south), City of Westminster (6 miles south-west), Marylebone (5 miles south-west), Kensington (8 miles south-west), St Pancras (4 miles south-west) and Shoreditch (4 miles south).
Local landmarks in Seven Sisters
Around Seven Sisters, our work takes us to homes and buildings near No.8 Seven Sisters pub, Ada College and Chestnuts Park, among other places. Nearby too are Gladesmore Community School (within half a mile east) and Church of St Andrew (0.8 miles south). Seven Sisters has its own railway station: Seven Sisters station. Well-known places in the area include Montfichet's Tower (4.9 miles south) and The Mall Wood Green (1.7 miles north-west). Open spaces near Seven Sisters include Highgate Hill and Woodberry Wetlands.
Looking after it afterwards
Good habits help new joints last longer. Our tips:
- Don’t use solvent cleaners on the joint
- Clean frames with a soft cloth and soapy water
- Keep drainage slots and sill grooves clear
- Walk round the house once a year and look at the joints
On timber frames, keep the paintwork in good order, because bare, wet timber moves more and pulls at the joint. Keep paint off the silicone itself.
On timber windows, water behind the joint can lead to rot. Rotten timber needs a joiner, not a sealant, so early resealing is worth it.
What we cannot put right
A few problems are outside what sealant work can do:
- Faulty window hardware
- Damp problems in the wall away from the window
- Worn gaskets, brush seals or a door that has dropped
Not sure which it is? You can phone 0345 464 0079 or email us and we’ll tell you honestly before booking.
Joints and surfaces we work on
- uPVC windows
- Window sills
- Aluminium frames
- Composite doors
- Timber windows & doors
- Patio & French doors
Why deal with it now?
Not every sealant suits a window. Decorators’ caulk and bathroom silicone are not designed for outside joints that move. A low-modulus exterior sealant keeps its stretch through hot and cold weather. 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. Dealing with it early is far simpler.
Some things make a job bigger or smaller: 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 choose Mr Mastic in Seven Sisters
- A sealant colour to suit the surroundings
- Experience in homes, commercial sites and hotels
- Quality sealants from Arbo and Everbuild
- Full insurance on every job
See what affects the cost and customer reviews.
Do you need window mastic in Seven Sisters?
Joints that are too thin or too deep fail early. A thin smear across a wide gap has nothing to it, and a gap filled solid cannot flex. Backing rod sets the right depth.
Common reasons people contact us include:
- Old mastic that has gone black or come away
- Cracked sealant at the sill ends
- Whistling draughts around closed windows
- Gaps between the frame and the inside reveal
As a London address, Seven Sisters can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
Comparing quotes
- Who does the work, and how experienced they are
- How the joint is cleaned and prepared
- What guarantee comes with the work
- Whether all the old sealant comes out first