Greater London · England
Window Mastic in Hornsey
Mastic around window and door frames, sills and patio doors for householders, landlords and businesses in Hornsey. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Hard, cracked sealant around windows
- Gaps where the sill meets the wall
- Black, perished sealant on frames
Why it’s worth doing now in Hornsey
Redecorating is a good moment to renew the mastic. Fresh joints finish the job neatly. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and once it shows in Hornsey, the repair is bigger than a sealant job.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, any mould to treat, and whether we need extra access for height. We take all of that into account in your quote.
Why choose Mr Mastic in Hornsey
- Quality sealants from Arbo and Everbuild
- White, clear, grey or another colour, product permitting
- Rated 4.9 stars on Google
- Sanitary silicone with an anti-fungal additive in wet areas
Read our cost guide and customer reviews.
How we handle window mastic in Hornsey
The mastic around a window or door seals the gap between the frame and the wall. When it cracks, hardens or pulls away, draughts and rain get in. Our applicators cut it out and replace it with a flexible, weatherproof sealant. We work on uPVC windows, patio & French doors and timber windows & doors, and common reasons people get in touch are black, perished sealant on frames and untidy mastic left by window fitters.
London homes have every kind of window, from timber sashes in period terraces to aluminium and uPVC in newer blocks. Over the years, the sealant around them shrinks, cracks and pulls away, letting in draughts and water.
There’s a 12-month guarantee on every job, large or small.
- Where
- Hornsey (N8, N22)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Places near Hornsey
Other services in Hornsey
What sealant work cannot fix
A few problems are outside what sealant work can do:
- Damp problems in the wall away from the window
- A frame that has rotted at the joint
- Condensation trapped between the panes
Not sure which it is? You can call 0345 464 0079 or email us and we’ll tell you honestly before you book.
Where we work in Hornsey
- Aluminium frames
- uPVC windows
- Timber windows & doors
- Composite doors
- Patio & French doors
- Window sills
DIY versus a professional finish
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly.
The difference is mostly in the preparation and the product. We take joints back to clean, dry surfaces, and the sealant is chosen for how the joint moves and where it is, and the work is guaranteed for a year.
Common questions in Hornsey
I let a flat near Hornsey station. Can you help?
Yes, rental work is part of what we do. Just ring 0345 464 0079 or drop us an email and tell us about the property, and we will send you a clear quote.
Do you cover Hornsey for window mastic?
Yes. We work across London and the South East, and Hornsey is part of that. Just phone 0345 464 0079 or send us an email with a few details of the job, and we’ll give you a clear price.
Can you do the inside joint as well?
Yes. The outside joint keeps the weather out, and the inside joint stops draughts and finishes the reveal. We do one or both.
Is there any odour?
Sometimes, a little. Any smell clears as the sealant cures.
Which products do you use?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We explain the product when we quote.
Will resealing my frames help with draughts?
In many cases. The gap between frame and wall is a common source of draughts, and resealing inside and out closes it.
Do I have to be there?
We need access to the joints, so we’ll agree that with you when we book. Indoors, that normally means someone at home.
Can I add another job to the visit?
Yes, we can. Several rooms, windows or areas can go on one quote.
Surface by surface
Composite doors
A composite door normally sits in a plastic outer frame, so its perimeter joint is sealed much like a window. The bead is colour-matched to the frame.
Patio & French doors
Patio and French doors have the longest joints on most houses. Most leaks start at the bottom corners, so they get particular care.
How the visit works
A visit follows a simple pattern: we look at the joints together, protect the area around them, carry out the job and clear up. It usually takes a few hours for a few frames, or a day or more for a whole house. In a London area like Hornsey, the main things to plan are parking and access: 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.
- Where gaps are deep, backing rod goes in first.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- We clear up and check every joint is fully closed.
Getting ready for the visit
- Keep pets and children clear of the area while we work
- Try not to wet indoor joints just before the visit
- Mention any parking rules near the property
How to get a quote
A good description makes for an accurate quote. Tell us where the job is, what’s wrong and how much there is, and email photos if that’s easy.
Related advice
Looking after it afterwards
A little care helps the new joints last. We recommend:
- Look round the frames every year or so
- Paint up to the joint, not over it
- Avoid harsh chemicals near the mastic
- Wipe condensation off the frames
Timber frames need their paint kept up, because bare, wet timber moves more and pulls at the joint. Paint up to the joint, not over the silicone.
Wet, windy weather is when failed mastic shows itself, but resealing works best in dry conditions. Sorting cracked mastic early means the joint is sound before the bad weather.
Windows and doors in Hornsey
London and the South East are among the drier parts of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Bruce Castle (about 2 miles north-east) nearby, there’s older building stock in the area around Hornsey 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.
If you look after a building such as St Mary's CofE Primary School, its window and door frames need their mastic kept sound, just like a home’s. Letting a property close to Hornsey station? Then cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. Homes close to Church of Holy Innocents include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Hornsey is about 3 miles east of Finchley, in Greater London. Jobs in Hornsey get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. We cover 764 towns and villages across Greater London, large and small. There’s also a page for London, about 6 miles away.
Jobs for window mastic in N8 and N22 works the same way as everywhere else we cover. Window mastic is available to properties on High Street, Brandon Place and Cross Lane and the roads around them. Neighbouring places we cover for window mastic include Turnpike Lane (1 mile east), Crouch End (1 mile south-west), Stroud Green (1 mile south-east), Wood Green (1 mile north-east) and Noel Park (1 mile north-east). We also work in nearby towns such as London (6 miles south), City of Westminster (5 miles south), Marylebone (5 miles south), Kensington (7 miles south-west), St Pancras (4 miles south) and Shoreditch (5 miles south).
Landmarks near Hornsey
Around Hornsey, our work takes us to homes and buildings near Great Northern Railway pub, Priory Park and Greek Secondary School of London, among other places. There’s a railway station in Hornsey itself: Hornsey station. Other landmarks nearby include Hornsey Central Hospital (0.7 miles west) and Broomfield House Museum (2 miles north). Not far away are Darland's Lake and Highgate Hill.
What affects the cost of window mastic
There’s no set price list. What we look at:
- The number and length of the joints
- Whether the work is at height
- The type of sealant required
- When we can work, for business premises
Homes and businesses are quoted the same way: the amount of work, how we reach it and what it needs. Call for a quick quote and we’ll explain what it covers.
Helping us quote
Before you ask for a quote, have a think about:
- Whether it has been sealed before
- The rough size of the job
- How we’d reach the joints
- What the problem is, such as mould, gaps, leaks or cracking
Want a quote for window mastic? Please ring 0345 464 0079 or send us an email and tell us about the job. We’ll explain what we’d do and give you a clear price before any work starts.