Greater London · England
Sand Mastic in Highgate
We cover Highgate for traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old material cut out, joints cleaned and sealed neatly.
- Failed mastic on an exposed elevation
- Mastic that needs renewing before redecorating
- Open joints round the window box
About our sand mastic in Highgate
Sand mastic suits most period window surrounds. On modern frames we’d normally use a flexible sealant, and we’ll talk through which suits your home. We work on brick reveals, tenement windows and period & listed homes, and people most often call us about a silicone bead on a sash window that spoils the look and mastic round period door frames that has failed.
Many London homes are flats, with windows high above the street. In a converted house or block, the lease usually says who is responsible for the windows, so it’s worth checking before booking, and access in Highgate is something to talk through when you book.
We stand behind the work with a 12-month guarantee.
- Place
- Highgate (N6, N19, NW5)
- Region
- Greater London
- Cover
- A year, on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Landlords, agents and businesses in Highgate
We work for landlords and agents as well as householders. Sealant work between tenants is a simple way to keep a property in good order before the next move-in.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We have worked in hotels as well as homes and businesses.
Looking after it afterwards
Once the sealant has cured, a few habits help it last:
- Clear gutters so water does not pour onto the windows
- Take care around the mastic when scraping paint
- Don’t paint over the new mastic
- Don’t run silicone over sand mastic
Check the mastic when you check the paintwork. Small cracks are easier to deal with early.
An open joint round the box lets weather through. Left, the gap tends to get bigger.
How the job changes by surface
Timber door frames
Door frames get knocked and soaked and the mastic can crack early. We rake it out and renew it.
Stone surrounds
We take care not to mark the stone while raking out the old mastic.
FAQs for Highgate
Is parking an issue for sand mastic in Highgate?
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.
Is Highgate in your area for sand mastic?
Yes, Highgate is within the area we cover. We work across London and the South East. Just call 0345 464 0079 or send us an email with a few details of the job, and we’ll give you a clear quote.
Is it possible to paint over sand mastic?
Traditional guidance is not to paint over sand mastic. If you’re redecorating the window, ask us first and we will advise.
Is consent needed for window work on a listed home?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like but the decision is theirs.
Which products do you use?
Each joint gets the product that suits it. Where it moves, gets wet or faces the weather makes a difference, and we will tell you what we’re using.
How long does the job take?
As a guide, most jobs take anything from a few hours to a full day, depending on how many windows. Bigger jobs take longer, and we’ll tell you how long to expect.
How much does sand mastic cost in Highgate?
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.
Can you replace silicone on a period window with sand mastic?
In most cases. The silicone is cut out and the joint cleaned before the sand mastic goes in.
What sand mastic looks like in Highgate
Rainfall in the South East is lower than in much of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day. With historic houses such as Witanhurst (about 0.4 miles south-west) nearby, there’s older building stock in the area around Highgate as well as newer homes. In older buildings, 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 Michael's Church of England Primary School, its window and door frames need their mastic kept sound, just like a home’s. Rented homes near Upper Holloway station change hands often, and older sash windows in a rental need their mastic kept sound to keep the weather out. Highgate is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Highgate is about 2 miles north-east of Hampstead, in Greater London. Whether you are in the middle of Highgate or further out, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. 764 places in Greater London are on our list, large and small.
Jobs for sand mastic in N6, N19 and NW5 is quoted and booked the same way as anywhere else. That includes homes and businesses on Wood Lane, Grange Road and Talbot Road. We also cover the places around Highgate: Upper Holloway (1 mile south-east), Dartmouth Park (1 mile south), Lissenden Gardens (1 mile south), Crouch End (1 mile north-east) and Tufnell Park (1 mile south-east). Within a short drive, we also cover London (5 miles south-east), City of Westminster (4 miles south), Marylebone (4 miles south), Kensington (6 miles south-west), St Pancras (3 miles south) and Shoreditch (4 miles south-east).
Near you in Highgate
We work in homes and buildings around The Angel Inn, St Aloysius RC College and Whittington Park. The closest station to Highgate is Upper Holloway station, about 0.9 miles south-east. Other landmarks nearby include Highgate Private Hospital (0.6 miles north-west) and Montfichet's Tower (4.4 miles south-east). Green spaces nearby include Darland's Lake and Parkland Walk.
Honest limits
In fairness, some problems need a different trade:
- Sashes that need overhauling
- Broken panes
- Damaged stone surrounds
If in doubt, ring 0345 464 0079 or drop us an email and we will say what we think before booking.
Surfaces we seal
- Sash and case windows
- Tenement windows
- Timber door frames
- Stone surrounds
- Brick reveals
- Period & listed homes
DIY sealant or a professional job?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
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.
What we do, step by step
When we get to you, we compare the joints with what we discussed. If anything is different, we explain it before carrying on. After that, the work takes a few hours per window, depending on the condition of the joints. In a London area like Highgate, the main things to plan are parking and access: tell us about permits, visitor bays or off-street space, which floor we are working on and whether there’s a lift.
- We look at the surrounds with you and agree the joints to renew.
- We remove the old, loose mastic.
- Deep gaps are packed so the mastic sits at the right depth.
- The sand mastic is mixed and pressed into the joint by hand.
- The surface is finished to suit the stone or brick.
How to prepare
- Try not to wet indoor joints just before the visit
- Tell us about access, such as stairs, a lift or high-level joints
- Keep pets and children clear of the area while we work
Getting a quote
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. You’ll have a clear quote before work begins.
Read more
Why deal with it now?
Draughts round a sash window are not always the sashes. Open mastic joints round the box can let air in, and renewing the mastic closes them. Converted houses in London often have a bathroom above someone else’s living room, and a slow leak from a failed seal can end up in the flat below. Putting it right early is much less trouble.
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. Call for a quick quote and we’ll explain what it covers.
Why Highgate clients choose us
- Fully insured
- Tidy, careful work
- Anti-fungal sanitary silicone in wet areas
- Homes, businesses and hotels
Take a look at our cost guide or what customers say.