Hertfordshire · England
Sand mastic for sash & case windows in Thorley, Hertfordshire
Specialist sand mastic for Thorley: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Cement or filler used on old window joints that has cracked
- Mastic that needs renewing before redecorating
- Weathered mastic on the most exposed windows
Why it’s worth doing now in Thorley
Gaps round a sash window let in rain and draughts. Water can get to the frame and the masonry so renewing it early protects the window. Around Thorley, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
Rather than a set price list, we look at what your job involves: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Why choose Mr Mastic in Thorley
- Every job guaranteed for a year
- Any old sealant cut out fully, not covered over
- 20+ years of sealant experience
- Neat joints and a tidy finish
Take a look at what affects the cost and customer reviews.
Sand mastic in Thorley
For a listed home or one in a conservation area, ask your local planning authority whether consent is needed for work to windows. Like-for-like sand mastic is often the preferred finish. If you’re dealing with window mastic to renew ahead of painting and a silicone bead on a sash window that spoils the look, we can help, on stone surrounds, sash and case windows and timber door frames alike.
Mastic can only go onto a dry, clean joint, so window work in Thorley is booked around the forecast. Let us know about access to all the frames, upstairs ones included.
The work is covered for a year after we finish. If there’s a problem with it, please phone 0345 464 0079 or email us.
- Place
- Thorley (CM23)
- Wider area
- Hertfordshire
- Cover
- 12 months on all our work
- Quotes
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Work for landlords, hotels and businesses
Mouldy or split sealant often shows up at the end of a tenancy. Several properties can go on one quote.
Hotels need rooms back in use, so we plan the work room by room. We have worked in hotels as well as homes and businesses.
Towns and villages near Thorley
Other services in Thorley
Aftercare tips
Aftercare is simple:
- Avoid patching sand mastic with silicone
- Ask us before painting near the mastic
- Keep sills and gutters clear so water drains away
- 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.
It’s best to renew mastic before painting the windows. Painting over failed mastic hides the problem for a while.
FAQs for Thorley
Can you help a landlord with a rental near Bishops Stortford station?
Yes, landlords and agents are among the people we work for. Just call 0345 464 0079 or drop us an email with the address and what needs doing, and we will give you a clear quote.
Will you come out to Thorley?
Yes, Thorley is covered. We work across London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Can old silicone round a sash window be swapped for sand mastic?
Yes. We remove the silicone and clean the joint before the sand mastic goes in.
Where do you work from?
Our base is in Crawley, West Sussex, and we cover South East England, London and all of Scotland.
Do you take out the old sealant first?
Yes, every time. New silicone doesn’t stick to old silicone, so any old material comes out before anything new goes in.
Which products do you use?
Quality sealants from brands including Arbo and Everbuild, chosen to suit the joint. We will tell you what we’re using and why.
What is sand mastic?
Sand mastic is a traditional material for pointing round windows and doors. It’s made with sand and a linseed-oil-based binder.
Is it OK to seal over old sealant?
No, it will not last. It may look fine at first, but the new bead soon lifts. The old sealant has to come out completely.
Common problems we fix in Thorley
Paint, silicone or cement used over old mastic causes problems. They do not move with the timber, and they usually need raking out.
Common reasons people contact us are:
- Draughts and rain around sash boxes
- Failed mastic on an exposed elevation
- Gaps where the frame meets the masonry
- Gaps round a timber door in stone or brick
If you look after a building such as Richard Whittington Primary School, the mastic around its windows and doors needs looking after like any other building’s.
Comparing quotes
- How the surfaces are prepared before sealing
- Are they insured?
- How the colour is chosen
- What happens if the job turns out different
What happens on the day
Good joint work is mostly preparation, so that is where we spend the time. Every joint is cleaned and dried before new material goes in. All told, the work takes a few hours for a single window, longer for several. In a small place like Thorley, access is usually the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- 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.
- The sand mastic is mixed and pressed into the joint by hand.
- The surface is finished to suit the stone or brick.
Before we arrive
- Mention any tricky access
- Clear the area around the work
- Try not to wet indoor joints just before the visit
How to get a quote
Every job is quoted individually, so the first step is telling us about yours. Just ring 0345 464 0079 or send us an email with the details.
Read more
Windows and doors in Thorley
Historic houses like Much Hadham Palace (about 2.9 miles west) are a reminder that the area around Thorley has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic. The South East is one of the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Letting a property close to Bishops Stortford station? Then any sash windows need sound mastic to keep draughts and rain out. In the older streets around Parish Church of St James the Great, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Thorley is about 1 mile south-west of Bishop's Stortford, in Hertfordshire. Every kind of property in Thorley can book us for sand mastic, old or new, large or small. The work is guaranteed for a year. 381 places in Hertfordshire are on our list. We also work in Chelmsford, around 17 miles away.
Work in CM23 works the same way as everywhere else we cover. If you are just outside Thorley, we cover Thorley Street (1 mile east), Spellbrook (1 mile south-east), Bishop's Stortford (1 mile north-east), Little Hallingbury (2 miles south-east) and Allen's Green (2 miles south-west). Further out, we also cover Stevenage (14 miles west), Welwyn Garden City (15 miles west), Hoddesdon (9 miles south-west), Cheshunt (13 miles south-west), Hertford (10 miles west) and Ware (8 miles west).
Around Thorley
Locally, jobs take us to homes and businesses close to Coach And Horses Public House and The Bishop's Stortford High School, among other places. The closest station to Thorley is Bishops Stortford station, about 1.5 miles north-east. A little further out are Bishops Stortford Local History Museum (2.4 miles north) and Moated mound (3 miles north-west). Not far away are Portingbury Hills and Thorley Wash nature reserve.
When it is not the sealant
We’ll always be straight with you, so here’s what new sealant will not do:
- Broken panes
- Sashes that rattle, stick or won’t open
- Crumbling stone or brickwork round the window
If in doubt, call 0345 464 0079 or send us an email and we will say what we think before you book.
What we seal
- Sash and case windows
- Stone surrounds
- Timber door frames
- Tenement windows
- Brick reveals
- Period & listed homes
Should I try it myself first?
The biggest DIY mistake is sealing over old sealant. Silicone doesn’t stick to old silicone, so it peels away and traps moisture behind it. Everything old must be removed first.
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.