Greater London · England
Sand mastic for sash & case windows in Cheam, Greater London
Window and door surrounds in Cheam need attention? We cut out the old, prepare the joints and apply the right sealant, with a 12-month guarantee.
- Mastic worn away on windows facing the weather
- Gaps where the frame meets the masonry
- Draughts and rain around sash boxes
Cheam questions
Can you do sand mastic in Cheam?
Yes. Our work covers London and the South East, and Cheam is part of that. You can call 0345 464 0079 or drop us an email and tell us what needs doing, and we’ll give you a clear quote.
Is parking an issue for sand mastic in Cheam?
Parking in Cheam, as in most of London, takes a little planning: a visitor permit or a nearby bay makes the day run more smoothly.
Can old silicone round a sash window be swapped for sand mastic?
Often, yes. With the silicone removed and the joint cleaned we point it with sand mastic.
What guarantee comes with the work?
Every job comes with our 12-month guarantee, and we are fully insured.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. Our applicators cover Cheam, along with the rest of our area.
Can I choose the sealant colour?
We help you choose a colour that suits, from white and clear to greys and other shades. The product needed can limit the range.
How long does the job take?
That depends on how much there is to do, but as a guide it takes anything from a few hours to a full day, depending on how many windows. We will give you a better idea when we quote.
I’m a tenant. Can you help?
We can work for tenants, landlords or agents. Just make sure your landlord agrees.
How we handle sand mastic in Cheam
On many period windows, sand mastic looks right and suits the building. On modern frames we’d normally use a flexible sealant, and we will talk through which suits your home. We work on period & listed homes, stone surrounds and brick reveals, and people most often call us about open joints round the window box and crumbling sand mastic round a window.
Many London homes are flats, with windows high above the street. Who looks after the outside of the frames can depend on the lease, so check that first, and access in Cheam is something to talk through when you book.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we’ll sort it.
- Location
- Cheam (SM2, SM3, SM1)
- Wider area
- Greater London
- Cover
- A year, on every job
- Price
- A clear price before work begins
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Do you need sand mastic in Cheam?
Previous repairs in cement or silicone often trap water or crack away. They do not suit the joint and we normally remove them.
The most common problems we see are:
- Weathered mastic on the most exposed windows
- Mastic that needs renewing before redecorating
- Draughty sash windows at the surround
- Gaps round a timber door in stone or brick
If you live in an older home near Church of St Andrew, the joint between an old wall and a newer frame is normally the first place rain gets in.
What to look for in a quote
- Are they insured?
- Who does the work, and how experienced they are
- When the joint can take water or movement
- Is the old sealant removed completely?
Frames and glazing around Cheam
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. In London conversions and blocks, the lease decides who is responsible for the frames, so check that before booking.
As a London address, Cheam can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. Managing a site like Glaisdale School? Then larger buildings have plenty of frames, and the mastic around each one ages.
Cheam is about 1 mile south-west of Sutton, in Greater London. Across the SM2 area, our applicators can take on sand mastic. Across Greater London, we cover 764 places, Cheam among them. You can also see our page for London, roughly 12 miles from Cheam.
Here we cover the SM2, SM3 and SM1 postcode area for sand mastic. If you need sand mastic at a property on Wray Road, York Road and The Avenue or a nearby road, we can help. Close by, we work in Belmont (1 mile south-east), Cuddington (1 mile north-west), North Looe (1 mile south-west), North Cheam (2 miles north) and Nork (2 miles south). Further out, we also cover London (12 miles north-east), City of Westminster (12 miles north), Marylebone (12 miles north), Kensington (11 miles north), St Pancras (13 miles north) and Shoreditch (14 miles north-east).
Near you in Cheam
Typical jobs here are in homes near Avenue Primary Academy, Howell Hill and Overton Grange School. The nearest railway station is Cheam station, about 0.6 miles north of the centre. Other landmarks nearby include The Ashley Centre (2.7 miles south-west) and Chessington Castle Hill (3.5 miles west). The countryside around Cheam includes Duppas Hill and Belmont Pastures.
How to look after the new joints
Joint life depends on how it’s used and looked after. We suggest:
- Ask us before painting near the mastic
- Go gently near the mastic when preparing windows
- Keep modern sealant off the mastic
- Make sure water runs off the sill
Leave the new mastic unpainted, which is the traditional advice. If you’re redecorating, ask us first.
Fine cracks show the mastic is starting to fail. It’s easier to renew it before it drops out.
DIY sealant or a professional job?
Some jobs are best left to a professional: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
Nearby places to Cheam
Also in Cheam
How the job changes by surface
Sash and case windows
The box of a sash and case window sits in the stone or brick opening. Sand mastic seals the joint round it.
Tenement and terrace windows
Upper-floor windows need access planning. Tell us the height and we’ll confirm what’s needed.
How we quote for sand mastic
We quote each job individually. These are the things that affect it:
- The number and length of the joints
- How easy the joints are to reach
- Working hours on commercial sites
- The product the joint needs
Commercial jobs are quoted on the same basis as homes: 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 to tell us for a quote
The more you tell us, the more accurate the quote. When you ask for a quote, tell us:
- The address or postcode of the job
- Whether it has been sealed before
- If it’s domestic, commercial or a hotel
- A few pictures by email, if you can
If you are in Cheam and need sand mastic, ring 0345 464 0079 or send us an email. Tell us what the problem is and where, and you will get a clear quote before any work starts.
What we can’t put right
We’d rather tell you now than do work that won’t last, so here’s what sealant cannot put right:
- Sashes that rattle, stick or won’t open
- Decisions on consent for listed homes
- Cracked or broken glass
Not sure which it is? You can ring 0345 464 0079 or email us and we’ll tell you honestly before booking.
What we seal
- Timber door frames
- Stone surrounds
- Brick reveals
- Period & listed homes
- Tenement windows
- Sash and case windows
How the visit works
We work through the job in order: protect, prepare, seal, tidy. For most jobs that takes a few hours per window, depending on the condition of the joints, and the area is left clean. 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.
- We look at the surrounds with you and agree the joints to renew.
- We remove the old, loose mastic.
- Deep gaps are packed so the mastic sits at the right depth.
- We apply the mastic by hand and shape it.
- We dress the finish so it sits neatly against the masonry.
How to prepare
- Tell us if parking is tricky
- Keep children and pets away from the work area
- Tell us about any water getting in
Get a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we will talk you through what we’d do. When it suits you, phone 0345 464 0079 or email us.