Kent · England
Sand mastic for sash & case windows in Coursehorn, Kent
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in Coursehorn, with a 12-month guarantee on every job. Ask us for a quote.
- Mastic worn away on windows facing the weather
- Mastic round period door frames that has failed
- Draughty sash windows at the surround
How we handle sand mastic in Coursehorn
Sand mastic doesn’t last for ever, leaving gaps round the window. Renewing it closes the gap so the surround looks right again. We work on stone surrounds, timber door frames and sash and case windows, and people most often call us about cracked mastic round a front door frame and a silicone bead on a sash window that spoils the look.
Somewhere as small as Coursehorn, 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.
All our work comes with our 12-month guarantee.
- Location
- Coursehorn (TN17)
- Wider area
- Kent
- Cover
- One year on every job
- Quotes
- A clear price before work begins
- Telephone
- 0345 464 0079
- Updated
- 26 October 2026
How the visit works
We keep the work tidy and contained to the joints we are treating. Expect the work to take a few hours for a single window, longer for several, and we tell you how long to leave it before we go. Somewhere as small as Coursehorn, access is often the only tricky part. For outside work, also let us know about exposed walls and any outbuildings involved.
- We check each window surround and the condition of the joint.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic isn’t too thick.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Before we arrive
- Keep pets and children clear of the area while we work
- Move anything stored near the joints
- Let us know about parking restrictions
Get a quote
We don’t publish a price list. Instead, we give you a clear quote for your job. To get started, ring 0345 464 0079 or send us an email.
Related advice
Also near Coursehorn
What else we do in Coursehorn
Frames and glazing around Coursehorn
Rainfall in the South East is lower than in much of the UK, 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 St Dunstan, the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Coursehorn is about 12 miles south of Maidstone, in Kent. Anywhere in TN17, we cover sand mastic for homes and businesses. 922 places in Kent are on our list, large and small. There’s also a page for Crawley, about 32 miles away.
Every address in TN17 is covered for sand mastic. Other places close to Coursehorn include Baker's Cross (1 mile west), Cranbrook (1 mile west), Swattenden (1 mile south-west), Hartley (2 miles south-west) and Benenden (2 miles south-east). Within a short drive, we also cover Maidstone (12 miles north), Ashford (14 miles east), Royal Tunbridge Wells (13 miles west), Tonbridge (14 miles north-west), Kings Hill (14 miles north-west) and Foley Park (13 miles north).
Near you in Coursehorn
Typical jobs here are in homes near White Horse pub, Cranbrook Church of England Primary School and Crane Valley, among other places. Well-known places in the area include Sissinghurst Castle (1.7 miles north-east) and Sissinghurst Castle (1.7 miles north-east).
Common questions in Coursehorn
Do you cover smaller places like Coursehorn?
Yes, smaller places are covered as well as towns. We work across London and the South East. Just mention lanes, gates or anything else about the route when you book.
What guarantee comes with sand mastic in Coursehorn?
Every job comes with our one-year guarantee, wherever it is. We are fully insured, and an ARBOMaster approved applicator.
Will you leave a mess?
Very little: the area around the joints is protected first, and we clear up the old sealant and our materials before we leave.
Should I use sand mastic or silicone?
It depends on the window. On many period windows, sand mastic looks right and suits the building, while modern frames normally get a flexible sealant.
Do I have to be there?
It depends on the job. For work indoors, someone needs to let us in.
Is consent needed for window work on a listed home?
It’s best to ask your local planning authority first. Sand mastic is often favoured as like for like, but they decide.
Do you hold any approvals?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we’re part of it.
Can sand mastic be painted?
Sand mastic is normally left unpainted, as guidance on traditional windows advises. Ask us before decorating.
Landlords, agents and businesses in Coursehorn
From a single let to a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
We also work for property managers and facilities teams. Several sites can go on one quote.
Quotes for sand mastic in Coursehorn
Your quote is based on your job. We look at:
- How many areas need sealing
- The old material and how stubborn it is
- Any mould that needs treating
- How much there is to do
Combining jobs into one visit generally makes better use of the time than several visits, so tell us about everything that needs sealing. You’ll get one clear quote for the whole job.
What we need to know
You don’t need to know the technical terms. It helps if you can tell us:
- Roughly how big the job is
- Whether it’s a home or a business
- Where the job is, and your postcode
- Any access issues, like height or stairs
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we’ll explain what’s involved.
How to look after the new joints
How long the joints last depends on use and care. Here’s what we suggest:
- Check the mastic when you check the paintwork
- Leave the new mastic unpainted
- Check with your local planning authority if your home is listed
- Go gently near the mastic when preparing windows
Avoid sealing over the mastic with silicone. If anything cracks, get it looked at before trying a quick fix.
An open joint round the box lets weather through. Left, the gap tends to get bigger as more mastic falls out.
Why act early in Coursehorn
Gaps round a sash window let in rain and draughts. Left, water can reach the timber and the wall so renewing it early protects the window. Around Coursehorn, older homes often have timber in their floors and frames, where water from a failed joint can cause rot if it’s left.
What it costs depends on the amount of work, 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 Coursehorn
- 4.9 on Google from 180+ five-star reviews
- Fully insured
- ARBOMaster approved applicator
- Every job guaranteed for a year
Read what affects the cost and our reviews.
When to call us in Coursehorn
Some old mastic was never deep enough. Mastic that’s too thin cracks and drops out so we make sure the new mastic is the right thickness.
Keep an eye out for these signs:
- Mastic round period door frames that has failed
- Mastic dropping out of the joint
- Gaps between timber frames and stone or brick
- Weathered mastic on the most exposed windows
For site and facilities teams at buildings such as Cranbrook School, the mastic around its windows and doors needs looking after like any other building’s.
Before you book anyone
- Whether VAT is included
- Which sealant they’ll use, and why
- The length of the guarantee
- How the surfaces are prepared before sealing
Different surfaces, different methods
Sash and case windows
Sash windows are where we do most sand mastic work. Each joint round the box is raked out and renewed.
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.