Greater London · England
Sand mastic for sash & case windows in Smithfield, Greater London
Professional sand mastic in and around Smithfield, with old sealant always removed completely.
- Modern sealant on a period surround
- Weathered mastic on the most exposed windows
- Patchy fillers round a sash window
What sealant work can’t fix
Some problems need a builder, plumber or other trade rather than us:
- Sashes that need overhauling
- Damaged stone surrounds
- Timber that has rotted
Not sure which it is? You can call 0345 464 0079 or send us an email and we’ll tell you honestly before you book.
Where we work in Smithfield
- Sash and case windows
- Stone surrounds
- Brick reveals
- Period & listed homes
- Timber door frames
- Tenement windows
Sand mastic in Smithfield
Sand mastic has long been used to fill the joint between timber frames and masonry. It’s a mix of sand and a linseed-oil-based binder, applied by hand. On older homes, it suits the building far better than silicone. We work on sash and case windows, brick reveals and stone surrounds, and the jobs we see most are weathered mastic on the most exposed windows and mastic round period door frames that has failed.
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, letting in draughts and water.
You are covered for a year from the day we finish. If anything isn’t right with it, ring 0345 464 0079 or drop us an email.
- Place
- Smithfield (EC1V, EC1P, EC1R)
- Region
- Greater London
- Guarantee
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Updated
- 26 October 2026
What the job involves on each surface
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.
Period and listed homes
Period homes look their best with traditional materials.
DIY versus a professional finish
What a professional job adds is preparation and the right 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.
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs call for the right materials, safe access and experience.
How to look after the new joints
After the cure time, these simple habits help:
- Inspect the joints round the windows every year or so
- Keep sills and gutters clear so water drains away
- Leave the new mastic unpainted
- Keep modern sealant off the mastic
Make sure water drains away from the window surround. Constant wetting wears the mastic faster.
Good mastic helps keep the frame dry. Once it fails, water can sit against the timber, which can lead to rot.
Smithfield: your questions answered
Do you cover Smithfield for sand mastic?
Yes. We work across London and the South East, and Smithfield is part of that. You can call 0345 464 0079 or drop us an email and let us know what needs doing, and we’ll send you a clear quote.
I let a flat near Farringdon station. Can you help?
Yes, we work for landlords and letting agents. You can call 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.
How do I get a quote for sand mastic in Smithfield?
The cost depends on the size of the job, access and how much old sealant has to come out. Ask us for a quote and we’ll talk you through it.
Do you work for hotels and businesses?
Yes, regularly. Larger jobs can be planned room by room or area by area to suit the site.
Can I add another job to the visit?
Yes. More than one area can be quoted together.
Is it possible to take out silicone and use sand mastic instead?
Often, yes. With the silicone removed and the joint cleaned, sand mastic is applied by hand.
What exactly is sand mastic?
It’s a mix of sand and a linseed-oil-based binder. It’s applied by hand and shaped to suit the surround.
Do you remove the old sealant?
Yes, always, and completely. New sealant will not bond properly to old, so the joint is cleaned back first.
What happens on the day
Every visit runs the same way: we check the joints, protect the area around them, do the work and clear up. It normally takes anything from a few hours to a full day, depending on how many windows. In a London area like Smithfield, the main things to plan are parking and access: let us know about parking, the floor we’ll 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.
- Large voids are packed out first, so the mastic is not too thick.
- We mix the sand mastic and apply it by hand, shaping it to the joint.
- The finish is dressed so it sits neatly against the stone or brick.
How to prepare
- For business premises, tell us about site rules or sign-in
- Tell us about any water getting in
- Where the joints are inside, avoid wetting them before we arrive
How to get a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Advice
Quotes for sand mastic in Smithfield
Every job gets its own quote. This is what makes a difference:
- Which sealant suits the joint
- How many rooms, windows or areas are involved
- Whether there’s mould to deal with
- Whether the work is at height
Some things make a job bigger or smaller: the old material and how easily it comes out, any mould to treat, and whether the work is at height. We take all of that into account in your quote.
Helping us quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- Roughly how big the job is
- A few pictures by email, if you can
- Where the property is
- Access, such as stairs, a lift or height
We quote each job on its own. Simply call 0345 464 0079 or drop us an email and describe the job and send pictures if you have them.
Nearby places to Smithfield
Also in Smithfield
Smithfield homes and the weather
With historic houses such as Dr Johnson's House (about 0.3 miles south-west) nearby, there’s older building stock in the area around Smithfield 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. 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.
Rented homes near Farringdon station change hands often, and cracked sand mastic around sash windows lets in the draughts tenants complain about. Managing a site like Charterhouse Square School? Then the mastic around its windows and doors needs looking after like any other building’s.
Smithfield is about 1 mile north of London, in Greater London. Whether you are in the middle of Smithfield or further out, sand mastic is available for homes and businesses alike. 764 places in Greater London are on our list, from the larger towns to small villages.
Every address in EC1V, EC1P and EC1R is within our area for sand mastic. Local streets include Oat Lane, Shoe Lane and Long Lane, all of which we cover. With the A1 and A4 close by, Smithfield is simple for us to get to for sand mastic. We also cover the places around Smithfield: Farringdon (1 mile north), Blackfriars (1 mile south), Holborn (1 mile west), Temple Bar (1 mile south-west) and Clerkenwell (1 mile north). We also work in nearby towns such as Kensington (4 miles west), Walthamstow (6 miles north-east), Hampstead (4 miles north-west), Ruislip (14 miles west), Brompton (3 miles south-west) and Stockwell (4 miles south).
Landmarks near Smithfield
Locally, jobs take us to homes and businesses close to London Nautical School, Barts Health Archives and St Alban's Church of England Primary School. You’ll also find St Mary-at-Hill (1 mile south-east), Oriole pub (within half a mile south-west) and Postman's Park (under half a mile south-east). Smithfield has its own railway station: Farringdon station. A little further out are Montfichet's Tower (under half a mile south) and Postal Museum (within half a mile south-east). For a walk, there’s Ludgate Hill and St. James's Park Lake.
Common problems we fix in Smithfield
Timber frames move with the seasons. That movement opens up the mastic joint little by little.
Common reasons people contact us are:
- Crumbling sand mastic round a window
- Cracked mastic round a front door frame
- Patchy fillers round a sash window
- Gaps where the frame meets the masonry
For an older house near a landmark such as St Bartholomew-the-Less, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Before you book anyone
- Whether you can choose the colour
- Are they insured?
- How the surfaces are prepared before sealing
- What the quote includes, VAT included or not