Greater London · England
Hornsey Sand Mastic
Specialist sand mastic for Hornsey: careful preparation, the right product and tidy work. Ask us for a quick quote.
- Gaps between timber frames and stone or brick
- Cement or filler used on old window joints that has cracked
- Silicone on a period window that looks wrong
About our sand mastic in Hornsey
Traditional burnt sand mastic blends with stone and brick surrounds. It suits period and listed homes, where modern sealant can look out of place. We work on tenement windows, brick reveals and timber door frames, and people most often call us about weathered mastic on the most exposed windows and tired mastic found when preparing windows for paint.
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 Hornsey as anywhere.
We stand behind the work with a 12-month guarantee.
- Place
- Hornsey (N8, N22)
- Wider area
- Greater London
- Guarantee
- One year on every job
- Price
- A clear price before any work starts
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Can I do it myself?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas need the right product, the right access and the right method.
Too much sealant is as bad as too little. A thick, smeared bead looks untidy and does not move well, and the joint depth matters as much as the finish.
Windows and doors in Hornsey
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. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. 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.
In the older streets around Church of Holy Innocents, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. For landlords with property near Hornsey station, older sash windows in a rental need their mastic kept sound to keep the weather out.
Hornsey is about 3 miles east of Finchley, in Greater London. Whether you’re in the middle of Hornsey or further out, sand mastic is available for homes and businesses alike. Our area takes in 764 places across Greater London, large and small. Our London page covers work nearby.
Work in N8 and N22 is quoted and booked the same way as anywhere else. Local streets include High Street, Brandon Place and Cross Lane, all of which we cover. If you are just outside Hornsey, we cover 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). Within a short drive, we also cover 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).
Near you in Hornsey
Typical jobs here are in homes near Great Northern Railway pub, Priory Park and Greek Secondary School of London, among other places. Hornsey has its own railway station: Hornsey station. Nearby you’ll also find Hornsey Central Hospital (0.7 miles west) and Broomfield House Museum (2 miles north). Green spaces nearby include Darland's Lake and Highgate Hill.
Aftercare tips
To keep the joints looking good and working properly:
- Take care around the mastic when scraping paint
- Leave the new mastic unpainted
- Plan mastic work ahead of painting
- Ask the planning authority about consent for listed or conservation-area homes
Avoid sealing over the mastic with silicone. If you see a crack, ask us to take a look rather than patching it.
Once mastic starts to crumble, rain gets in. It can soak into the frame and the surrounding masonry so early renewal protects both.
Work for landlords, hotels and businesses
Failed sealant is one of the commonest items on a check-out report. Several properties can be quoted together.
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
What we’re called out for in Hornsey
Decorating can disturb tired mastic. Many people find it crumbling when they prepare the windows.
It’s worth asking for a quote if you see:
- Mastic worn away on windows facing the weather
- Gaps where the frame meets the masonry
- Draughts and rain around sash boxes
- Gaps round a timber door in stone or brick
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.
What to look for in a quote
- How the joint is cleaned and prepared
- Is the old sealant removed completely?
- Whether VAT is included
- How hidden problems are handled
Towns and villages near Hornsey
What else we do in Hornsey
Quotes for sand mastic in Hornsey
Jobs vary more than people expect. What affects the quote:
- How much there is to do
- Mould in or behind the old joints
- The product the joint needs
- How much old sealant there is and how hard it is to remove
The cost reflects the work involved, not a rough estimate. That’s why we ask about the job first and agree the price before starting.
What we need to know
When you call or email, these details help:
- The address or postcode of the job
- The type of property
- If someone has resealed it before
- A few photos by email, if you can
We don’t publish a price list. Instead, your job gets its own clear quote. To arrange one, phone 0345 464 0079 or email us.
How it works
We bring everything the job needs with us, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. It normally takes a few hours per window, depending on the condition of the joints. 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 the surrounds with you and agree what needs doing.
- Old, loose mastic is raked out and the joint cleaned.
- We pack any deep gaps so the mastic sits at the right depth.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
Preparing for the visit
- Clear the area around the work
- Where the joints are inside, avoid wetting them before we arrive
- Keep children and pets away from the work area
Get a quote
Getting a quote is simple: tell us what needs doing and where, and roughly how big it is. A few pictures by email make the job easier to understand, and we’ll take it from there.
Read more
Honest limits
We will always be straight with you, so here’s what sealant cannot fix:
- Sashes that rattle, stick or won’t open
- Damaged stone surrounds
- Timber that has rotted
If in doubt, call 0345 464 0079 or send us an email and we will say what we think.
Joints and surfaces we work on
- Stone surrounds
- Brick reveals
- Tenement windows
- Period & listed homes
- Sash and case windows
- Timber door frames
Common questions in Hornsey
Is Hornsey in your area for sand mastic?
Yes, Hornsey is within the area we cover. Our work covers London and the South East. You can call 0345 464 0079 or drop us an email and tell us what needs doing, and we’ll give you a clear price.
Can parking be tricky for a visit in Hornsey?
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.
What information do you need?
A short description and the location, with pictures by email if possible. We will ask anything else we need to know.
When will the new mastic be hard?
It skins over fairly quickly but takes longer to harden fully. We’ll explain what to expect before we leave.
Is it OK to seal over old sealant?
No. Fresh sealant does not stick to old sealant, and it traps any mould or water underneath. It all has to come out first.
Where is Mr Mastic based?
We are a Crawley-based firm. We work across South East England, London and Scotland.
How much does sand mastic cost in Hornsey?
We do not publish prices, because the cost depends on the job: how much there is, what’s there now, how we reach it and what it needs. We agree the price before any work begins.
I’m a tenant. Can you help?
Yes, though it’s best to check with your landlord first. Many landlords are glad to have it sorted.