Greater London · England
Sand mastic for sash & case windows in Harringay, Greater London
Sand mastic across Harringay and nearby, with old sealant always removed completely.
- Gaps round a timber door in stone or brick
- Old cement repairs round a window that have failed
- Wind and rain getting in round a sash window
Keeping the joints in good condition
A little care helps the new joints last. Our advice:
- Renew mastic before redecorating the windows
- Avoid patching sand mastic with silicone
- Take care around the mastic when scraping paint
- Make sure water runs off the sill
Avoid sealing over the mastic with silicone. If you see a crack, ask us to take a look rather than patching it.
It’s best to renew mastic before painting the windows. Painting over failed mastic hides the problem for a while.
About our sand mastic in Harringay
A silicone bead around a sash window can look out of place and does not suit the building. Sand mastic is the traditional choice, and we can replace one with the other. We work on timber door frames, stone surrounds and sash and case windows, and people most often call us about gaps round a timber door in stone or brick and window mastic to renew ahead of painting.
London has a lot of flats and conversions, where windows are often on upper floors. In a converted house or block, the lease normally says who is responsible for the windows, so it’s worth checking before booking.
The work is covered for a year after we finish. If anything is not right with it, ring 0345 464 0079 or email us.
- Place
- Harringay (N4, N15, N8)
- Region
- Greater London
- Guarantee
- One year on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Also near Harringay
What else we do in Harringay
What sand mastic looks like in Harringay
London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking.
If you let a flat or house near Harringay Green Lanes station, older sash windows in a rental need their mastic kept sound to keep the weather out. As a London address, Harringay can be tricky for parking: let us know about parking bays, permits or a driveway.
Harringay is about 2 miles north-west of West Hackney, in Greater London. From the centre of Harringay to the outskirts, we cover sand mastic for every kind of property. We cover 764 towns and villages across Greater London, from the larger towns to small villages. We also work in London, about 6 miles from Harringay.
Here we cover the N4, N15 and N8 postcode area for sand mastic. Sand mastic is available to properties on Elyne Road, Denton Road and Warham Road and the roads around them. Close by, we work in Duckett's Green (1 mile north), West Green (1 mile north-east), St Ann's (1 mile east), Manor House (1 mile south) and Seven Sisters (1 mile east). Larger places within reach include London (6 miles south), City of Westminster (5 miles south-west), Marylebone (5 miles south-west), Kensington (7 miles south-west), St Pancras (4 miles south) and Shoreditch (4 miles south).
Near you in Harringay
In Harringay, that means homes and buildings near Chestnuts Park, Park View School and Moselle Upper School, among other places. Also close by are The Salisbury pub (within half a mile north) and Church of St Andrew (1.1 miles south-east). There’s a railway station in Harringay itself: Harringay Green Lanes station. Other landmarks nearby include Montfichet's Tower (4.7 miles south) and Markfield Beam Engine and Museum (1.6 miles east). For a walk, there’s Railway Fields and Highgate Hill.
Do you need sand mastic in Harringay?
Sand mastic slowly weathers. It hardens, cracks and starts to come away on the stone or timber.
The problems people normally mention when they call are:
- Old sand mastic that has cracked, crumbled or fallen out
- Draughts and rain around sash boxes
- Gaps round a timber door in stone or brick
- Window mastic to renew ahead of painting
Schools such as South Harringay Infant School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages.
What your quote should include
- What happens if they find a problem under the old sealant
- Is the old sealant removed completely?
- Which colour the sealant will be
- What the cure time is
When it isn’t the sealant
We won’t take on work that won’t last, so these are the limits:
- Rotten sashes, sills or window boxes (a joiner’s job)
- Masonry that needs repairing
- Planning or listed building consent (your local planning authority decides)
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think.
Where we work in Harringay
- Sash and case windows
- Period & listed homes
- Timber door frames
- Brick reveals
- Tenement windows
- Stone surrounds
Landlords, agents and businesses in Harringay
Failed sealant is one of the commonest items on a check-out report. Several properties can go on one quote.
From a single let to a portfolio, you get the same standard of work: old sealant fully removed, joints prepared properly and a one-year guarantee.
DIY sealant or a professional job?
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so just mention it when you contact us.
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.
What the job involves on each surface
Tenement and terrace windows
Upper-floor windows need access planning. Tell us the height and we’ll confirm what’s needed.
Stone surrounds
Old stone surrounds are often uneven, so the gap isn’t the same all the way round. We shape it by hand to follow the stone.
Questions from Harringay
I let a flat near Harringay Green Lanes station. Can you help?
Yes, we work for landlords and agents. You can phone 0345 464 0079 or drop us an email with the address and a few details, and we will give you a fixed price before work begins.
Is parking a problem for a job in Harringay?
Parking in Harringay, as in most of London, takes a little planning: a visitor permit or a bay close to the door helps a lot.
Can I add another job to the visit?
Yes. Just list everything you need and we’ll quote it together.
Can old silicone round a sash window be swapped for sand mastic?
Often, yes. Once the silicone is out and the joint prepared we point it with sand mastic.
Is there any odour?
Some sealants have a smell while they cure, which fades as it sets. Ventilation helps.
Is it messy?
Tidy work is part of the job. Nearby surfaces are protected, and we clear up when we’re done.
Do you work in Harringay?
Yes. We work in Harringay and the rest of Greater London. To book, call 0345 464 0079 or email us.
Do you do commercial work?
Yes. Commercial and hotel work is a large part of what we do, as well as homes. Working times can be discussed when we quote.
What happens on the day
Every visit runs the same way: we check the joints, mask and protect the surrounding surfaces, carry out the job and clear up. It usually takes anything from a few hours to a full day, depending on how many windows. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in Harringay. It helps if you can point us to a visitor permit or a bay close to the door.
- First, we look at the surrounds with you and agree what needs doing.
- We rake out the old mastic and clean the joint.
- We pack any deep gaps so the mastic sits at the right depth.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- We dress the surface so it sits neatly against the masonry.
Getting ready for the visit
- Tell us about any previous sealing or DIY attempts
- Mention any tricky access
- Tell us if parking is tricky
Ask for a quote
For sand mastic in Harringay, call 0345 464 0079 or email us. Tell us what the problem is and where, and you will get a clear quote before we start.