Greater London · England
Sand mastic for sash & case windows in Gospel Oak, Greater London
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Gospel Oak and across Greater London. ARBOMaster approved applicators, fully insured, with a 12-month guarantee.
- Gaps where the frame meets the masonry
- Crumbling sand mastic round a window
- Silicone on a period window that looks wrong
Sand mastic in Gospel Oak
We work across Gospel Oak renewing sand mastic on sash windows and doors. Each joint is raked out, prepared and pointed by hand for a neat, traditional finish. Typical jobs include weathered mastic on the most exposed windows and crumbling sand mastic round a window, across brick reveals, sash and case windows and stone surrounds.
From mansion-block windows to modern glazing in new flats, London has every kind of frame. Over the years, the sealant around them shrinks, cracks and pulls away, which is when draughts and damp patches appear in homes in Gospel Oak.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we will sort it.
- Place
- Gospel Oak (NW5, NW3, NW1)
- Wider area
- Greater London
- Guarantee
- 12 months on all our work
- Quote
- A clear price before work begins
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
Aftercare tips
Looking after new joints is easy:
- Inspect the joints round the windows every year or so
- Plan mastic work ahead of painting
- Avoid heavy scraping on the mastic joint
- Clear gutters so water doesn’t pour onto the windows
Leave the new mastic unpainted, as traditional guidance advises. If you are redecorating, ask us first.
Renewing mastic before redecorating saves doing it twice. Painting over failed mastic hides the problem for a while.
FAQs for Gospel Oak
Can you do sand mastic in Gospel Oak?
Yes, Gospel Oak is within the area we cover. We work across London and the South East. Just call 0345 464 0079 or email us with a few details of the job, and we’ll give you a clear quote.
Can parking be tricky for a visit in Gospel Oak?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Should I try DIY first?
You can, for simple jobs. Preparation is everything: all the old sealant out, and a clean, dry joint. If it doesn’t work out, we can redo it.
What’s sand mastic made of?
It’s the traditional filler for the joint round timber windows and doors. It combines sand with a linseed-oil-based binder.
How long does sand mastic take to go off?
It takes a while. It skins first and hardens fully later and we’ll give you an idea for your job.
Is there any odour?
Sometimes, a little. It fades as the sealant cures.
Do I have to be there?
If the work is inside, we need someone to let us in. After that, you can carry on with your day.
Can old silicone round a sash window be swapped for sand mastic?
Generally, yes. Once the silicone is out and the joint prepared, sand mastic is applied by hand.
For landlords and businesses
If you manage several properties in or around Gospel Oak, jobs at different addresses can be quoted together. Just tell us the addresses and what each one needs, and pictures by email help.
Housing providers, facilities teams and property managers book us too. Several sites can be quoted together, and we’re fully insured.
What happens on the day
Good joint work is mostly preparation, so that is where we spend the time. Joints are cleaned back and dried before anything new goes in. In total, it normally takes a few hours for a single window, longer for several. For a job in Gospel Oak, parking and access are the things to plan: let us know about parking, the floor we will be working on and any lift or shared entrance.
- Each surround is checked first.
- We rake out the old mastic and clean the joint.
- We fill deep gaps so the new mastic is not too thick.
- New sand mastic is applied and shaped by hand.
- The finish is dressed neatly.
Before we arrive
- For indoor joints, keep the area dry beforehand if you can
- For business premises, tell us about site rules or sign-in
- Plan for the work area to be out of bounds to pets and children
How to get a quote
Want a quote for sand mastic? Please ring 0345 464 0079 or drop us an email and tell us about the job. We will explain what we’d do and give you a clear price before work begins.
Related advice
Common problems we fix in Gospel Oak
Shallow joints are a common cause. A thin layer doesn’t hold well so we make sure the new mastic is the right thickness.
Look out for these signs:
- Window mastic to renew ahead of painting
- Gaps between timber frames and stone or brick
- Old sand mastic that has cracked, crumbled or fallen out
- Silicone on a period window that looks wrong
As a London address, Gospel Oak can be tricky for parking: let us know about parking bays, permits or a driveway.
Questions to ask before booking
- Are they insured?
- How the colour is chosen
- Whether all the old sealant comes out first
- Is VAT in the price?
How we quote for sand mastic
Call for a quick quote. The main things that affect it are:
- Mould in or behind the old joints
- The type of sealant required
- How many rooms, windows or areas are involved
- The number and length of the joints
Homes and businesses are quoted the same way: the amount of work, the access and the products needed, along with when we can work on site. Ask us for a quote and we will explain what it covers.
What we need to know
You do not need to know the technical terms. It helps if you can tell us:
- What’s wrong with the joints now
- How we’d reach the joints
- Where the job is, and your postcode
- Photos by email, if that’s easy
To get a quote, ring 0345 464 0079 or send us an email with the location and a short description of the problem. You will have a clear quote before work begins.
Windows and doors in Gospel Oak
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. Historic houses like Keats House (about 0.9 miles west) are a reminder that the area around Gospel Oak has older buildings as well as new. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
For site and facilities teams at buildings such as Carlton Primary School, its window and door frames need their mastic kept sound, just like a home’s. In the older streets around Highgate Road Chapel, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Gospel Oak is about 1 mile east of Hampstead, in Greater London. Gospel Oak gets the same service as everywhere we cover: old sealant removed completely, careful preparation and a 12-month guarantee. Gospel Oak is one of 764 places in Greater London where we work.
We work across NW5, NW3 and NW1 for sand mastic. Sand mastic is available to properties on Rona Road, Dale Road and Regis Road. Nearby, we also carry out sand mastic in Lissenden Gardens (1 mile north), Dartmouth Park (1 mile north-east), Kentish Town (1 mile south), Tufnell Park (1 mile east) and Chalk Farm (1 mile south). Within a short drive, we also cover London (4 miles south-east), City of Westminster (3 miles south), Kensington (4 miles south-west), Shoreditch (4 miles south-east), Walthamstow (6 miles north-east) and Hoxton (3 miles south-east).
What’s near Gospel Oak
We work in homes and buildings around Vaughan Williams Memorial Library, St. Mary's Town and Country School and Bull and Gate pub, among other places. Nearby too are Parliament Hill (0.7 miles north-west) and Parliament Hill School (within half a mile north). Gospel Oak has its own railway station: Gospel Oak station. Well-known places in the area include Royal Northern Hospital (1.2 miles north-east) and O2 Centre (1.5 miles west). Open spaces near Gospel Oak include Belsize Wood and The Long Water.
Also near Gospel Oak
More services for Gospel Oak
Why act early in Gospel Oak
Not every draught comes from the sashes themselves. Gaps between the frame and the wall can be just as bad and new mastic seals them. In a flat in Gospel Oak, failed sealant seldom stays inside your own four walls: water from a shower or window joint can reach the flat below, and gaps in fire-stopping matter to everyone in the building.
Doing several joints on one visit generally makes better use of the time than several visits, so it’s worth mentioning everything you’d like done. You’ll get one clear quote for the whole job.
Why Gospel Oak customers choose us
- A 12-month guarantee on all work
- We leave the area clean and tidy
- We never seal over old sealant
- Homes, businesses and hotels
See what affects the cost and customer reviews.
How the job changes by surface
Brick reveals
Loose mastic comes out and deep gaps are packed before the new mastic goes in.
Period and listed homes
Period homes look their best with traditional materials.