Kent · England
Knave's Ash Sand Mastic
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for householders, landlords and businesses in Knave's Ash. Fully insured, ARBOMaster approved and guaranteed for a year.
- Draughty sash windows at the surround
- A silicone bead on a sash window that spoils the look
- Gaps round a timber door in stone or brick
How we handle sand mastic in Knave's Ash
Fresh sand mastic forms a skin quite soon but full hardening takes longer. Traditionally, sand mastic is left unpainted, so ask us before you decorate. Typical jobs include draughty sash windows at the surround and silicone on a period window that looks wrong, on tenement windows, sash and case windows and stone surrounds.
Somewhere as small as Knave's Ash, older homes often have timber frames set in stone or brickwork. Older buildings like these don’t always suit modern silicone, and sometimes a traditional sand mastic is the better choice.
A one-year guarantee comes with the work, just as it does everywhere we cover.
- Where
- Knave's Ash (CT3)
- Wider area
- Kent
- Guarantee
- 12 months on all our work
- Quotes
- A clear price before work begins
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Landlord and commercial work in Knave's Ash
We also work for businesses, from offices to washrooms and kitchens. On commercial sites, working times can be discussed when we quote.
We work for landlords and letting agents as well as homeowners. Sealant work between tenants keeps a property looking cared for.
Knave's Ash questions
Do you work for landlords with property near Herne Bay station?
Yes. We work for landlords and agents as well as homeowners. Just phone 0345 464 0079 or send us an email with the address and what needs doing, and we’ll send you a clear quote.
Do you cover smaller places like Knave's Ash?
Yes, Knave's Ash is covered. We work across London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
What is sand mastic?
It’s sand mixed with a linseed-oil-based binder, used between timber frames and stone or brick.
Do you take out the old sealant first?
Yes. We cut out all the old sealant and clean the joint before resealing.
Do I have to be there?
For indoor joints, yes, someone needs to let us in. After that, you can carry on with your day.
How do I get a quote for sand mastic in Knave's Ash?
We do not publish prices, because the cost depends on the job: its size, the old material, access and the product needed. We agree the price before any work begins.
Can you quote for more than one area?
Yes. Tell us about everything you’d like done and you will get one quote.
Can you replace silicone on a period window with sand mastic?
Often, yes. With the silicone removed and the joint cleaned we point it with sand mastic.
How it works
We keep the work tidy and contained to the area we’re working on. The job usually takes a few hours for a single window, longer for several, and we tell you how long to leave it before we go. For a village or hamlet like Knave's Ash, the journey is planned in advance: tell us about narrow lanes, gates, long drives and where we can park. Everything for the job comes with us, so a second trip is avoided where possible.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- Deep voids are packed so the mastic is the right thickness.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The mastic is finished to sit tidily against the stone or brick.
Getting ready for the visit
- Clear the area around the work
- Try not to wet indoor joints just before the visit
- For business premises, tell us about site rules or sign-in
Ask for a quote
We quote each job on its own, so the first step is telling us about yours. Just call 0345 464 0079 or email us with the details, and photos are welcome.
Related advice
Different surfaces, different methods
Period and listed homes
On a listed home or in a conservation area, the right material matters. Sand mastic is often the preferred finish.
Stone surrounds
Old stone surrounds are often uneven, so the gap is not the same all the way round. We shape it by hand to follow the stone.
Should I try it myself first?
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.
A careful DIYer can reseal a simple joint, 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.
When to call us in Knave's Ash
Shallow joints are a common cause. Mastic that’s too thin cracks and drops out so we make sure the new mastic is the right thickness.
Signs it’s time to call us include:
- Failed mastic on an exposed elevation
- Gaps where the frame meets the masonry
- Mastic dropping out of the joint
- A silicone bead on a sash window that spoils the look
For landlords with property near Herne Bay station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
What your quote should include
- Which sealant they’ll use, and why
- The length of the guarantee
- When the joint can take water or movement
- How much experience the applicator has
What else we do in Knave's Ash
Looking after it afterwards
No joint lasts for ever, but care makes a real difference. Our tips:
- Clear gutters so water doesn’t pour onto the windows
- Have rotten timber repaired before new mastic goes in
- Look over the window mastic once a year
- Take care around the mastic when scraping paint
Avoid sealing over the mastic with silicone. If you see a crack, ask us to take a look before trying a quick fix.
Sound mastic protects the frame. Failed mastic lets water reach the timber and timber that stays wet can rot.
Knave's Ash homes and the weather
Knave's Ash is close to the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. That’s hard on the mastic around older windows and doors, especially on the side facing the sea. 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.
If you live in an older home near Church of the Holy Cross, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint. If you look after a building such as Hoath Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Knave's Ash is about 2 miles south of Herne Bay, in Kent. Jobs in Knave's Ash get the same care as everywhere else we work: the old material taken out, joints prepared properly and a 12-month guarantee. Our Kent coverage runs to 922 places, and Knave's Ash is one of them. There’s also a page for Chelmsford, about 40 miles away.
We cover every part of CT3 for sand mastic. Sand mastic is available to properties on Hicks Forstal Road and Hoath Road. We also cover the places around Knave's Ash: Hoath (1 mile east), Maypole (1 mile north-east), Old Tree (1 mile north-east), Millbank (1 mile north-east) and Hicks Forstal (1 mile west). Larger places within reach include Canterbury (5 miles south-west), Margate (10 miles east), Dover (15 miles south-east), Ramsgate (11 miles east), Broadstairs (12 miles east) and Whitstable (5 miles west).
Landmarks near Knave's Ash
We work in homes and buildings around Curtis Wood and Spires Academy. Knave's Ash’s nearest station is Herne Bay station, roughly 2.6 miles north-west of the centre. A little further out are St Martins Hospital (4.4 miles south-west). Green spaces nearby include West Blean and Thornden Woods.
Why deal with it now?
Filling over old, loose mastic does not last. Raking out and preparing the joint gives it a sound base so the new mastic stays put. Around Knave's Ash, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
What it costs depends on how much there is to do, how hard the old material is to remove and how easy the joints are to reach. You’ll have a clear quote before any work starts.
Why choose Mr Mastic in Knave's Ash
- 20+ years of sealant experience
- Trusted Arbo and Everbuild sealants
- Domestic, commercial and hotel work
- Tidy, careful work
See our cost guide or what customers say.