Greater London · England
Sand Mastic in New Malden
Our applicators work in New Malden on traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old material cut out, joints cleaned and sealed neatly.
- A silicone bead on a sash window that spoils the look
- Old cement repairs round a window that have failed
- Failed mastic on an exposed elevation
When to call us in New Malden
Water gets into small cracks in the mastic and loosens it further. Exposed elevations normally fail first.
These are the problems we are asked about most:
- Tired mastic found when preparing windows for paint
- Crumbling sand mastic round a window
- Wind and rain getting in round a sash window
- Weathered mastic on the most exposed windows
For site and facilities teams at buildings such as Christ Church New Malden CofE Primary School, its window and door frames need their mastic kept sound, just like a home’s.
What your quote should include
- Is the old sealant removed completely?
- Whether you can choose the colour
- How long the guarantee is
- Whether they’re fully insured
About our sand mastic in New Malden
Silicone on a period window often looks wrong and doesn’t suit the building. Sand mastic gives a finish that matches the age of the house, and we can replace one with the other. We work on brick reveals, sash and case windows and timber door frames, and the jobs we see most are mastic that needs renewing before redecorating and open joints round the window box.
Many London homes are flats, with windows high above the street. In a converted house or block, the lease usually says who is responsible for the windows, so it’s worth checking before booking, and access in New Malden is something to talk through when you book.
There’s a 12-month guarantee on every job, whatever its size.
- Location
- New Malden (KT3, KT1, SW20)
- Wider area
- Greater London
- Cover
- One year on every job
- Quotes
- A clear quote up front
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
Leave it or put it right?
New mastic over crumbling mastic will not hold. Raking out and preparing the joint gives it a sound base so the new mastic stays put. In older London homes, water behind a failed joint soaks into brick and timber without much sign, and by the time it shows on a wall or ceiling in New Malden, the repair is bigger than the sealant job would have been.
What you pay reflects the work, not guesswork. That’s why we ask a few questions first.
Why choose Mr Mastic in New Malden
- Anti-fungal silicone where joints get wet
- We never seal over old sealant
- Full insurance on every job
- Domestic, commercial and hotel work
Take a look at what affects the cost or our reviews.
Frames and glazing around New Malden
Compared with the north and west, the South East gets less rain, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast. With historic houses such as Southside House (about 1.6 miles north-east) nearby, there’s older building stock in the area around New Malden as well as newer homes. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
Letting a property close to New Malden station? Then any sash windows need sound mastic to keep draughts and rain out. As a London address, New Malden can be tricky for parking: let us know about parking bays, permits or a driveway.
New Malden is about 3 miles south-west of Wimbledon, in Greater London. Jobs in New Malden get the same care as everywhere else we work: old sealant removed completely, careful preparation and a 12-month guarantee. Our area takes in 764 places across Greater London. You can also see our page for London, about 10 miles away.
Every address in KT3, KT1 and SW20 is within our area for sand mastic, from the main roads to the quietest streets. If you need sand mastic at a property on High Street, Ashcombe Square and Melrose Gardens or anywhere close by, we can help. New Malden sits on or near the B283, so getting to you is simple. Other places close to New Malden include Motspur Park (1 mile north-east), West Barnes (1 mile east), Norbiton (1 mile north-west), Coombe (1 mile north) and Raynes Park (1 mile east). Further out, we also cover London (10 miles north-east), City of Westminster (9 miles north-east), Marylebone (9 miles north-east), Kensington (7 miles north), St Pancras (11 miles north-east) and Shoreditch (12 miles north-east).
What’s near New Malden
We work in homes and buildings around Beverley Park, The Glasshouse pub and Holy Cross School and the streets around them. There’s a railway station in New Malden itself: New Malden station. A little further out are Chessington Castle Hill (3.3 miles south) and Bentall Centre (1.9 miles west). For a walk, there’s Rose Walk and Kingston Hill Road area.
How it works
Good joint work is mostly preparation, so that’s where we spend the time. Every joint is cleaned and dried before new material goes in. All told, the work takes a few hours per window, depending on the condition of the joints. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in New Malden. It helps if you can point us to a visitor permit or a bay close to the door.
- First we agree which joints need doing.
- 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.
- The surface is finished to suit the stone or brick.
Preparing for the visit
- Tell us about any water getting in
- Tell us about access, such as stairs, a lift or high-level joints
- Where the joints are inside, avoid wetting them before we arrive
How to get a quote
Quotes start with a quick conversation. Tell us what’s wrong, where it is and how much there is, and we’ll explain how we’d tackle it. When it suits you, phone 0345 464 0079 or send us an email.
Advice
Quotes for sand mastic in New Malden
The quote reflects the job in front of us. We take into account:
- Whether the work is at height
- How many rooms, windows or areas are involved
- Which sealant suits the joint
- How much old sealant there is and how hard it is to remove
Commercial jobs are quoted on the same basis as homes: the amount of work, how we reach it and what it needs, along with when we can work on site. Ask us for a quote and we will go through it with you.
Asking for a quote
Photos help, but a description is a good start. Please mention:
- Photos by email, if that’s easy
- Where the property is
- What’s wrong with the joints now
- If it’s domestic, commercial or a hotel
For a quick quote, get us on the phone, or send an email if you’d rather. Describe what needs sealing and we’ll talk you through the work.
How the job changes by surface
Stone surrounds
Sand mastic sits naturally against stone. The finish blends with the masonry.
Period and listed homes
Sand mastic is the like-for-like choice for many period homes. On listed buildings, check with your planning authority first.
Aftercare tips
Joint life depends on how it’s used and looked after. We suggest:
- Go gently near the mastic when preparing windows
- Renew mastic before redecorating the windows
- Get any rot dealt with first
- Inspect the joints round the windows every year or so
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 and timber that stays wet can rot.
Honest limits
Before you book, it’s worth knowing the limits:
- Damaged stone surrounds
- Decisions on consent for listed homes
- Rotten sashes, sills or window boxes (a joiner’s job)
If you’re not sure, just ring 0345 464 0079 or send us an email and we’ll give you a straight answer.
Surfaces we seal
- Period & listed homes
- Stone surrounds
- Tenement windows
- Brick reveals
- Sash and case windows
- Timber door frames
Places near New Malden
More services for New Malden
Your questions about sand mastic in New Malden
Do you work for landlords with property near New Malden station?
Yes, we work for landlords and letting agents. You can call 0345 464 0079 or send us an email with the address and a few details, and we’ll give you a fixed price before any work starts.
Can parking be tricky for a visit in New Malden?
In much of London, parking needs planning: a visitor permit or a nearby bay makes the day run more smoothly.
What information do you need?
Where the job is, what the problem is and roughly how big it is. If you can, email a few pictures.
Should I use sand mastic or silicone?
It depends on the window. On many period windows, sand mastic looks right and suits the building and newer frames normally get a flexible sealant.
Can old silicone round a sash window be swapped for sand mastic?
Yes, we do this often. The old silicone has to come out completely so the mastic beds in well.
What’s sand mastic made of?
Sand plus a binder based on linseed oil. It’s applied by hand and finished to sit neatly against the masonry.
When will the new mastic be hard?
A skin forms quite soon, but full hardening takes longer. We’ll tell you what to expect for your job.
How long does sand mastic take?
That depends on how much there is to do, but most jobs take anything from a few hours to a full day, depending on how many windows. We’ll tell you when we quote.