Greater London · England
Kensington Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for householders, landlords and businesses in Kensington. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Gaps where the frame meets the masonry
- Mastic dropping out of the joint
- Modern sealant on a period surround
What we can’t put right
Before you book, it’s worth knowing the limits:
- Broken panes
- Planning or listed building consent (your local planning authority decides)
- Sash cords, weights and draught-proofing of the sashes
If you are not sure, just phone 0345 464 0079 or send us an email and we’ll give you a straight answer.
Joints and surfaces we work on
- Sash and case windows
- Period & listed homes
- Tenement windows
- Brick reveals
- Timber door frames
- Stone surrounds
Sand mastic for homes and businesses in Kensington
A silicone bead around a sash window can look out of place and is not always the right material. Sand mastic is the traditional choice and we can swap the silicone for it. Common call-outs are for failed mastic on an exposed elevation and wind and rain getting in round a sash window, on tenement windows, sash and case windows and period & listed homes.
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 Kensington.
There’s a 12-month guarantee on every job, whatever its size.
- Where
- Kensington (W11, W8, W14, SW7)
- Region
- Greater London
- Guarantee
- One year on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Signs you need sand mastic in Kensington
Paint, silicone or cement used over old mastic causes problems. They do not move with the timber and we normally remove them.
If you can see any of these, it’s time to have the joints looked at:
- Modern sealant on a period surround
- Weathered mastic on the most exposed windows
- Old cement repairs round a window that have failed
- Mastic dropping out of the joint
As a London address, Kensington can be tricky for parking: tell us about permits, visitor bays or off-street space when you book.
What your quote should include
- Whether all the old sealant comes out first
- Who does the work, and how experienced they are
- What happens if they find a problem under the old sealant
- What insurance they hold
Aftercare tips
A little care helps the new joints last. We recommend:
- Avoid patching sand mastic with silicone
- Check with your local planning authority if your home is listed
- Leave the new mastic unpainted
- Sort the mastic before the decorators arrive
Look at the mastic when you look over the windows. Small cracks are easier to deal with early.
An open joint round the box lets weather through. Left, the gap tends to get bigger as more mastic falls out.
Why act early in Kensington
A silicone bead can be quicker, but on period stone or brick it often looks out of place. Sand mastic is the traditional material and blends with the stone or brick. Converted houses in London often have a bathroom above someone else’s living room, so a small leak from tired sealant can mean a neighbour’s ceiling and a lot of disruption. Putting it right early is much less trouble for homes in Kensington.
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed. Call for a quick quote and we’ll explain what it covers.
Why choose Mr Mastic in Kensington
- 4.9 on Google from 180+ five-star reviews
- Old sealant always removed completely
- Quality sealants from Arbo and Everbuild
- Approved under the ARBOMaster scheme
Different surfaces, different methods
Period and listed homes
Materials matter on listed and conservation-area homes. Sand mastic is often the preferred finish.
Sash and case windows
A sash window’s box frame sits in the masonry opening. The gap round it is pointed with sand mastic.
What we do, step by step
We bring everything the job needs with us, so there’s nothing for you to buy. Once we’ve agreed what’s being done, the area is protected and the work begins. It normally takes a few hours for a single window, longer for several. Many London jobs are in flats, so we come ready for stairs, narrow hallways and shared entrances. If the building has a concierge, managing agent or access rules, tell us when you book.
- Each surround is checked first.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic isn’t too thick.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Before we arrive
- On commercial sites, let us know about site rules
- Mention any leaks or damp you’ve noticed
- Keep children and pets away from the work area
How to get a quote
For sand mastic in Kensington, call 0345 464 0079 or send us an email. Tell us what the problem is and where, and you will get a clear quote before we start.
Read more
Kensington homes and the weather
In a converted house or block, who looks after the windows depends on the lease, so it’s worth checking before booking. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
For an older house near a landmark such as Church of St Barnabas, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. If you let a flat or house near Kensington Olympia station, any sash windows need sound mastic to keep draughts and rain out.
Kensington is about 5 miles west of London, in Greater London. Our applicators cover sand mastic for homeowners, landlords and businesses in Kensington. Our area takes in 764 places across Greater London.
Jobs for sand mastic in W11, W8, W14 and SW7 is quoted and booked the same way as anywhere else. If you need sand mastic at a property on Kensington High Street, Edwardes Square and Somerset Square or anywhere close by, we can help. Being close to the A402 and B316, Kensington is easy for our applicators to reach for sand mastic. Neighbouring places we cover for sand mastic include Holland Park (1 mile north), Notting Hill (1 mile north), Shepherd's Bush (1 mile west), Notting Dale (1 mile north) and White City (1 mile north-west). Larger places within reach include London (5 miles east), Marylebone (3 miles north-east), St Pancras (4 miles north-east), Shoreditch (6 miles east), Walthamstow (10 miles north-east) and Hoxton (6 miles north-east). Being one of Greater London’s larger places, Kensington has homes, rented property and businesses of every kind.
Landmarks near Kensington
In Kensington, that means homes and buildings near Holland Park, Scarsdale Tavern and Holland Park School, among other places. Also close by are Kensington School (0.5 miles east) and Abdus Salam Library (1 mile east). There’s a railway station in Kensington itself: Kensington Olympia station. Nearby you will also find Kensington Arcade (less than half a mile east) and London Museum (0.7 miles north-east). Not far away are WWT London Wetland Centre and The Long Water.
Quotes for sand mastic in Kensington
The price is agreed before any work begins. It takes into account:
- How much there is to do
- How much old sealant there is and how hard it is to remove
- The type of sealant required
- How many rooms, windows or areas are involved
Every job is a little different, so we quote each one individually. Size, access and the product the joint needs all make a difference, and we’ll explain the quote if you ask.
What we need to know
To make quoting easier, let us know:
- What the problem is, such as mould, gaps, leaks or cracking
- Where the job is, and your postcode
- Access, such as stairs, a lift or height
- The type of property
Getting a quote is simple: let us know what needs doing and where, and roughly how big it is. A few photos by email make the job easier to understand.
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Common questions in Kensington
Is parking an issue for sand mastic in Kensington?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
Is Kensington in your area for sand mastic?
Yes. Our work covers London and the South East, and Kensington is part of that. You can phone 0345 464 0079 or send us an email and tell us what needs doing.
Do you do commercial work?
Yes. We work in offices, washrooms, hotels and other commercial premises, as well as homes. Working times can be discussed when we quote.
Can new sealant go over the old?
No, because it fails. The old sealant always comes out first, so the new joint bonds to clean surfaces.
Do I need to be at home?
Access is agreed with you when the job is booked. Indoors, that generally means someone at home.
What should I tell you?
Only a few details: where it is, what you’ve noticed and how we reach it. Then phone 0345 464 0079 or send us an email.
Is it messy?
Very little: the area around the joints is protected first, and we clear up the old sealant and our materials before we leave.
What does sand mastic cost?
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 will talk you through it.