City of London · England
Sand Mastic in City of London
Window and door surrounds in City of London need attention? We cut out the old, prepare the joints and apply the right sealant, with a one-year guarantee.
- Gaps where the frame meets the masonry
- Wind and rain getting in round a sash window
- Modern sealant on a period surround
Sand mastic in City of London
Silicone on a period window often looks wrong and does not suit the building. Sand mastic is the traditional choice and we can swap the silicone for it. We work on brick reveals, sash and case windows and period & listed homes, and people most often call us about patchy fillers round a sash window and weathered mastic on the most exposed windows.
Many London homes are flats, with windows high above the street. In a converted house or block, the lease generally says who is responsible for the windows, so it’s worth checking before booking, and access in City of London is something to talk through when you book.
We guarantee the work for a year. If something isn’t right with it in that time, tell us and we will put it right.
- Where
- City of London (EC4V, EC1A, EC2M, EC2Y)
- Region
- City of London
- Cover
- 12 months on all our work
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Can I do it myself?
Too much sealant is as bad as too little. A heavy bead looks messy and copes badly with movement, and the joint depth matters as much as the finish.
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
What we cannot put right
Some problems need a builder, plumber or other trade rather than us:
- Sashes that rattle, stick or won’t open
- Whether work needs listed building consent
- Decayed frames that need repair
Not sure which it is? You can phone 0345 464 0079 or email us and we’ll tell you honestly.
Joints and surfaces we work on
- Period & listed homes
- Brick reveals
- Tenement windows
- Stone surrounds
- Sash and case windows
- Timber door frames
Sand mastic in City of London: local notes
In a converted house or block, who looks after the windows depends on the lease, so check that before booking. Compared with the north and west, the South East gets less rain, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
City of London is in London, so parking needs planning: tell us about permits, visitor bays or off-street space when you book. If you look after a building such as Fashion Retail Academy, the mastic around its windows and doors needs looking after like any other building’s. Homes close to St Olave Old Jewry include some older properties, and replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
City of London is about 1 mile north of London, in City of London. For sand mastic in and around City of London, it’s easy to get a quote: please phone 0345 464 0079 or drop us an email. We are based in Crawley and cover City of London.
Jobs for sand mastic in EC4V, EC1A, EC2M and EC2Y works the same way as everywhere else we cover. You will find streets such as Aldermanbury Square, Monkwell Square and Paternoster Square, and we cover them all. Being close to the A1 and A3, City of London is easy for our applicators to reach. We also cover the places around City of London: Barbican Estate (1 mile north), Bishopsgate (1 mile east), Finsbury (1 mile north), Aldgate (1 mile east) and St Luke's (1 mile north).
Local landmarks in City of London
We work in homes and buildings around St Mary-at-Hill, Prior Weston Primary School and Children's Centre and Golden Fleece pub and the streets around them. Also close by are Central Foundation Boys' School (0.8 miles north), Barts Health Archives (within half a mile north-west) and St Alphage Garden (within half a mile north). City of London has its own railway station: London Cannon Street station. A little further out are Gabriel's Wharf (0.8 miles south-west) and London Mithraeum (within half a mile south). The countryside around City of London includes St. James's Park Lake and Barnsbury Wood.
Common questions in City of London
Do you work for landlords with property near London Cannon Street station?
Yes, we work for letting agents and landlords. Just call 0345 464 0079 or drop us an email and tell us about the property, and we will give you a clear price.
Is City of London in your area for sand mastic?
Yes, City of London is within the area we cover. We work across London and the South East. Just ring 0345 464 0079 or email us with a few details of the job.
Can I do it myself?
You can, for simple jobs. Preparation is everything: all the old sealant out, and a clean, dry joint. We can always put it right if it fails.
What exactly is sand mastic?
Sand plus a binder based on linseed oil. It’s applied by hand and shaped to suit the surround.
Can you match the sealant colour?
Yes. Sealants come in white, clear, grey and other colours for many products, and we agree the colour with you before any work starts.
Is there any odour?
Some sealants have a smell while they cure, but it fades. Ventilation helps.
Do I need permission for sand mastic on a listed building?
Check with your local planning authority. They decide whether consent is needed.
Where are you based?
Our base is Crawley. We work across South East England, London and Scotland.
Landlords, agents and businesses in City of London
Housing providers, facilities teams and property managers book us too. Several sites can go on one quote, and we are fully insured for the work.
Whether it’s one flat or a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
How it works
We keep the work tidy and contained to the joints we’re treating, so you can get on with your day. The job generally takes a few hours per window, depending on the condition of the joints, and we explain the cure time before we leave. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. Mention any building rules, key holders or managing agents when you book.
- First, we look at the surrounds with you and agree what needs doing.
- The loose and crumbling mastic is raked out and the joint cleaned.
- Deep voids are packed so the mastic is the right thickness.
- 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
- Tell us about access, such as stairs, a lift or high-level joints
- Let us know about parking restrictions
- Tell us about any water getting in
Getting a quote
We do not publish a price list, because every job is different. Instead, your job gets its own clear quote. To arrange one, phone 0345 464 0079 or email us.
Read more
Towns and villages near City of London
What else we do in City of London
Different surfaces, different methods
Period and listed homes
On a listed home or in a conservation area, the right material matters. Sand mastic is often the preferred finish.
Stone surrounds
Sand mastic sits naturally against stone. It finishes to look like part of the surround.
Looking after it afterwards
No joint lasts for ever, but care makes a real difference. A few tips:
- Go gently near the mastic when preparing windows
- Plan mastic work ahead of painting
- Look over the window mastic once a year
- Find out about consent before window work on a listed home
Avoid painting over the new mastic, as traditional guidance advises. If you’re redecorating, ask us first.
Fine cracks show the mastic is starting to fail. Renewing it then is simpler than waiting until it falls out.
What affects the cost of sand mastic
For a quick quote, just ask. The main things that affect it are:
- The size of the job
- Access and height
- How many areas need sealing
- The type of sealant required
What you pay reflects the work, not a rough estimate. That is why we ask about the job first.
What we need to know
A few details help us give you an accurate quote. When you get in contact, it helps to mention:
- Access, such as stairs, a lift or height
- How many joints, rooms or windows are involved
- A few photos by email, if you can
- What’s wrong with the joints now
For a quote, phone 0345 464 0079 or send us an email with the location and a short description of the problem. We’ll give you a clear price before any work starts.