Greater London · England
The Wrythe Sand Mastic
Sand mastic for The Wrythe, by sealant specialists with 20+ years’ experience. Rated 4.9 on Google from 180+ five-star reviews.
- Gaps between timber frames and stone or brick
- Silicone on a period window that looks wrong
- Old sand mastic that has cracked, crumbled or fallen out
Common questions in The Wrythe
Do you cover The Wrythe for sand mastic?
Yes, The Wrythe is within the area we cover. We work across London and the South East. You can phone 0345 464 0079 or email us and let us know what needs doing, and we will send you a clear quote.
Is parking a problem for a job in The Wrythe?
It can be, so it helps to tell us about permits, visitor bays or off-street space when you book. The visit is then planned around what’s available.
Do you work for landlords and businesses?
Yes, regularly. Several properties can be quoted together.
Where do you work from?
We work from Crawley. Our applicators cover The Wrythe, along with the rest of our area.
I’m a tenant. Can you help?
Yes. Ask your landlord first, and we can send them the quote if that helps.
What do you need from me for a quote?
Only a few details: the address or postcode, what’s wrong and any access issues. Then phone 0345 464 0079 or drop us an email.
Is there any odour?
Sometimes, a little. Any smell clears as the sealant cures.
Is it OK to seal over old sealant?
No, because it fails. The old sealant always comes out first, so the new joint bonds to clean surfaces.
Sand mastic in The Wrythe, done properly
If your home is listed or in a conservation area, check with your local planning authority whether consent is needed for work to windows. Sand mastic is often favoured as a like-for-like material. Common call-outs are for wind and rain getting in round a sash window and mastic worn away on windows facing the weather, across tenement windows, brick reveals and stone surrounds.
London has a lot of flats and conversions, where windows are often on upper floors. 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 The Wrythe 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.
- Place
- The Wrythe (SM5, SM6, SM1)
- Wider area
- Greater London
- Guarantee
- A year, on every job
- Quotes
- A clear quote up front
- Call
- 0345 464 0079
- Last updated
- 26 October 2026
Also near The Wrythe
Also in The Wrythe
Landlords, agents and businesses in The Wrythe
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. We can quote for more than one property at once.
From a single let to a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
When it isn’t the sealant
It helps to know what we cannot do:
- Sash cords, weights and draught-proofing of the sashes
- Timber that has rotted
- Damaged stone surrounds
If in doubt, phone 0345 464 0079 or drop us an email and we’ll say what we think before you book.
What we seal
- Brick reveals
- Tenement windows
- Period & listed homes
- Timber door frames
- Stone surrounds
- Sash and case windows
What happens on the day
When we get to you, we check the joints match what you told us. If we find something unexpected, we talk it through with you first. After that, the work takes a few hours for a single window, longer for several. Parking in much of London is by permit or pay-and-display, so it helps to know what’s near you in The Wrythe. A visitor permit or a nearby bay makes the visit run more smoothly.
- First, we look at the surrounds with you and agree what needs doing.
- Old, loose 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.
- The finish is dressed so it sits neatly against the stone or brick.
Getting ready for the visit
- Let us know if you’ve seen damp or leaks
- Mention any parking rules near the property
- Keep pets and children clear of the area while we work
Ask for a quote
To get a quote, ring 0345 464 0079 or drop us an email and tell us where the job is and what the problem looks like. You’ll have a clear quote before work begins.
Related advice
Looking after it afterwards
How long the joints last depends on use and care. Here’s what we suggest:
- Take care around the mastic when scraping paint
- Leave the new mastic unpainted
- Make sure water runs off the sill
- Get any rot dealt with first
Make sure water drains away from the window surround. Water sitting against the mastic shortens its life.
Fine cracks show the mastic is starting to fail. It’s easier to renew it before it drops out.
Surface by surface
Sash and case windows
The box of a sash and case window sits in the stone or brick opening. The gap round it is pointed with sand mastic.
Tenement and terrace windows
In shared buildings, the windows may be part of a wider repair, so check who is responsible first.
Why deal with it now?
New mastic over crumbling mastic won’t hold. We remove the loose material first so the new work lasts. In a flat in The Wrythe, failed sealant seldom stays inside your own four walls: water can reach the neighbours below, and gaps in fire-rated joints affect the whole building.
What it costs depends on the size of the job, how much old material has to come out and access to the work. You’ll have a clear quote before any work starts.
Why choose Mr Mastic in The Wrythe
- 180+ five-star Google reviews
- An ARBOMaster approved applicator
- 20+ years of sealant experience
- Fully insured
Should I try it myself first?
Sealing over old silicone is the commonest DIY error. New silicone will not bond to old, so it peels away and traps moisture behind it. Everything old must be removed 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.
Windows and doors in The Wrythe
In a converted house or block, who looks after the windows depends on the lease, so check that before you book. With historic houses such as Nonsuch Mansion (about 2.9 miles west) nearby, there’s older building stock in the area around The Wrythe 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.
In the older streets around Bishop Andrewes Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame. As a London address, The Wrythe can be tricky for parking: tell us about permits, visitor bays or off-street space when you book. Letting a property close to Carshalton station? Then cracked sand mastic around sash windows lets in the draughts tenants complain about.
The Wrythe is about 7 miles south of Stockwell, in Greater London. For sand mastic in and around The Wrythe, it’s easy to get a quote: please phone 0345 464 0079 or send us an email. We cover Greater London from our Crawley base. The Wrythe is one of 764 places in Greater London where we work for sand mastic. For nearby work, see our London page (9 miles or so).
All of SM5, SM6 and SM1 is covered for sand mastic. You will find streets such as Elm Road, Byne Road and Mill Lane, all of which we cover. If you’re just outside The Wrythe, we cover Carshalton (1 mile south), Wallington (1 mile south-east), Rosehill (1 mile north-west), St Helier (1 mile north-west) and Benhilton (1 mile west). Further out, we also cover London (9 miles north), City of Westminster (10 miles north), Marylebone (10 miles north), Kensington (9 miles north), St Pancras (11 miles north) and Shoreditch (11 miles north).
Landmarks near The Wrythe
Typical jobs here are in homes near Carshalton Park, The Railway Tavern and Carshalton High School for Girls, among other places. There’s a railway station in The Wrythe itself: Carshalton station. Other landmarks nearby include Centrale Croydon (2.7 miles east) and Honeywood Museum (0.6 miles south). For a walk, there’s The Spinney Local Nature Reserve and Duppas Hill.