Greater London · England
Sand Mastic in Merton Park
Professional sand mastic in and around Merton Park, with every bit of old sealant taken out first and a 12-month guarantee.
- Cement or filler used on old window joints that has cracked
- Crumbling sand mastic round a window
- Silicone on a period window that looks wrong
How the job changes by surface
Tenement and terrace windows
Rows of sash windows on tenements and terraces often need renewing together. We can do one window or several.
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.
Sand mastic in Merton Park
Our applicators renew the sand mastic around sash and case windows and doors set in stone or brick. Out comes the old, loose mastic, and new mastic is applied and shaped by hand. If you have draughty sash windows at the surround and window mastic to renew ahead of painting, we can put it right, on timber door frames, sash and case windows and tenement windows alike.
Much of London’s older housing was built with timber sash windows, some still in place and some long since replaced. Whatever is in the opening now, the joint between frame and wall is what keeps the weather out, in Merton Park as anywhere.
You are covered for a year from the day we finish. If anything is not right with it, ring 0345 464 0079 or email us.
- Location
- Merton Park (SW19, SW20, SM4)
- Wider area
- Greater London
- Cover
- A year, on every job
- Quote
- A clear price before work begins
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Looking after it afterwards
So the new joints stay in good condition:
- Do not paint over the new mastic
- Avoid heavy scraping on the mastic joint
- Keep sills and gutters clear so water drains away
- Get any rot dealt with first
Avoid painting over the new mastic, as traditional guidance advises. If you’re redecorating, ask us first.
Renewing mastic before redecorating saves doing it twice. Painting over failed mastic hides the problem for a while.
How it works
On the day, we start by going over the job with you. We protect the surfaces around the joints before any work begins. Most jobs take 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.
- 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.
- We pack any deep gaps so the mastic sits at the right depth.
- Sand mastic is mixed and applied by hand, then shaped to the joint.
- We dress the surface so it sits neatly against the masonry.
Before we arrive
- Clear items away from the joints we’re working on
- Let us know if you’ve seen damp or leaks
- Plan for the work area to be out of bounds to pets and children
Ask for a quote
Asking for a quote is easy: let us know what needs doing and where. Photos by email help us understand the job, and we will take it from there.
Advice
Merton Park homes and the weather
In London conversions and blocks, the lease decides who is responsible for the frames, so it’s worth checking before booking. With historic houses such as Southside House (about 1.4 miles west) nearby, there’s older building stock in the area around Merton Park as well as newer homes. Where a home is older, older timber frames in brick or stone need a different approach from a modern uPVC window.
For site and facilities teams at buildings such as Merton Park Primary School, larger buildings have plenty of frames, and the mastic around each one ages. Merton Park is in London, so parking needs planning: let us know about parking bays, permits or a driveway.
Merton Park is about 1 mile south-east of Wimbledon, in Greater London. Whether you are in the middle of Merton Park or further out, sand mastic is available for homes and businesses alike, from flats and houses to offices and hotels. Merton Park is one of 764 towns and villages in Greater London where we work. You can also see our page for London, roughly 8 miles from Merton Park.
Here we cover the SW19, SW20 and SM4 postcode area for sand mastic. Local streets include Mina Road, Manor Road and Cecil Road, all of which we cover. Neighbouring places we cover for sand mastic include Wimbledon Chase (1 mile west), Bushey Mead (1 mile west), Cannon Hill (1 mile south-west), Wimbledon (1 mile north-west) and Crooked Billet (1 mile north-west). Larger places within reach include London (8 miles north-east), City of Westminster (7 miles north), Marylebone (8 miles north), Kensington (6 miles north), St Pancras (9 miles north-east) and Shoreditch (10 miles north-east).
Around Merton Park
Typical jobs here are in homes near Wibbas Down Inn, Morden Hall Park and Wimbledon School of Art, among other places. The nearest railway station is South Merton station, about 0.5 miles south. Other landmarks nearby include St George's Hospital (1.6 miles north-east) and Southside Wandsworth (3.1 miles north). Green spaces nearby include Merton Park Green Walks and Henman Hill.
Why deal with it now?
New sash windows are a major, costly change, and in listed buildings it may need consent. If the frames are sound, renewing the mastic deals with gaps and draughts at the surround. 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. Dealing with it early is far simpler.
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. Your quote takes all of that into account.
What you get with us
- Sanitary silicone with an anti-fungal additive in wet areas
- Trusted Arbo and Everbuild sealants
- 4.9 on Google from 180+ five-star reviews
- Homes, businesses and hotels
Places near Merton Park
More services for Merton Park
Should I try it myself first?
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you’re set on DIY, put the effort into preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
When it is not the sealant
To be straight with you, there are a few things sealant won’t fix:
- Planning or listed building consent (your local planning authority decides)
- Sash cords, weights and draught-proofing of the sashes
- Crumbling stone or brickwork round the window
If in doubt, ring 0345 464 0079 or send us an email and we will say what we think.
What we seal
- Tenement windows
- Stone surrounds
- Period & listed homes
- Sash and case windows
- Brick reveals
- Timber door frames
Signs you need sand mastic in Merton Park
Over the years, sand mastic weathers. It dries out, cracks and loses its grip on the stone or timber.
Most people get in touch when they notice one of these:
- Old sand mastic that has cracked, crumbled or fallen out
- A silicone bead on a sash window that spoils the look
- Patchy fillers round a sash window
- Gaps between timber frames and stone or brick
In the older streets around St Mary's Church, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
What to look for in a quote
- When the joint can take water or movement
- Whether you can choose the colour
- What guarantee comes with the work
- How much experience the applicator has
Common questions in Merton Park
Can you help a landlord with a rental near South Merton station?
Yes, landlords and agents are among the people we work for, and several properties can be quoted together. Just phone 0345 464 0079 or email us with the address and what needs doing, and we will send you a clear quote.
Is parking a problem for a job in Merton Park?
London parking needs a little planning, so let us know about permits, bays or a driveway when you book. The visit is then planned around what’s available.
Can you work on commercial sites?
Yes. We have worked for hotels, offices and other businesses and we are fully insured.
Which is right for my windows, sand mastic or modern sealant?
We will talk it through with you. Sand mastic suits many period homes and newer frames suit modern sealant.
Do you work in Merton Park?
We do. Merton Park is part of the area we cover.
Is it possible to take out silicone and use sand mastic instead?
Yes, it’s a common request. The old silicone has to come out completely so the mastic beds in well.
Will it make a mess?
Tidy work is part of the job. Nearby surfaces are protected.
Can you quote for more than one area?
Yes. Several rooms, windows or areas can go on one quote.