Dumfries and Galloway · Scotland
Sand mastic for sash & case windows in Thornhill, Dumfries and Galloway
Traditional burnt sand mastic around sash and case windows and doors in stone and brick in Thornhill, with a 12-month guarantee on every job. Call for a quick quote.
- A silicone bead on a sash window that spoils the look
- Open joints round the window box
- Gaps round a timber door in stone or brick
Sand mastic for homes and businesses in Thornhill
We renew sand mastic around sash windows and doors in stone and brick. Out comes the old, loose mastic, the joint is prepared and new mastic is shaped by hand. We work on period & listed homes, brick reveals and timber door frames, and the jobs we see most are old cement repairs round a window that have failed and silicone on a period window that looks wrong.
Mastic can only go onto a dry joint, so outside work in Thornhill depends on the weather, and longer journeys are planned in advance. Tell us about access to all the windows and doors, upstairs included.
Big or small, you get the same one-year guarantee.
- Place
- Thornhill (DG3)
- Region
- Dumfries and Galloway
- Guarantee
- A year, on every job
- Quotes
- Quoted before any work starts
- info@mrmastic.co.uk
- Updated
- 26 October 2026
For landlords and businesses
We also work for property managers and facilities teams. We can quote a run of properties together, and we’re fully insured for the work.
Whether it’s one flat or a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
Also near Thornhill
More services for Thornhill
What we can’t put right
We will not take on work that will not last, so these are the limits:
- Sash cords, weights and draught-proofing of the sashes
- Whether work needs listed building consent
- Timber that has rotted
If you are not sure, just send an email to info@mrmastic.co.uk and we will give you a straight answer before you book.
What we seal
- Period & listed homes
- Tenement windows
- Sash and case windows
- Timber door frames
- Stone surrounds
- Brick reveals
What the job involves on each surface
Tenement and terrace windows
Rows of sash windows on tenements and terraces often need renewing together. We work on single windows or whole elevations.
Stone surrounds
We take care not to mark the stone when the old mastic comes out.
What affects the quote in Thornhill
The price is agreed before any work begins. It’s based on:
- When we can work, for business premises
- The type of sealant required
- Whether old sealant or filler has to be cut out
- Whether there’s mould to deal with
Combining jobs into one visit generally makes better use of the time than several visits, so tell us about everything that needs sealing. You will get one clear quote for the whole job.
Asking for a quote
To help us quote quickly, let us know:
- Whether it has been sealed before
- Access, such as stairs, a lift or height
- The problem you’ve noticed
- How many joints, rooms or windows are involved
Getting a quote is simple: let us know what needs doing and where and its rough size. A few pictures by email make the job easier to understand, and we will come back to you with a quote.
Questions from Thornhill
Is sand mastic in Thornhill guaranteed?
Every job comes with our one-year guarantee, wherever it is. We’re fully insured, and an ARBOMaster approved applicator.
Will you come out to Thornhill?
Yes, smaller places are covered as well as towns. Our work covers the whole of Scotland. Let us know about access, parking and anything unusual about getting there when you book.
What do you put in the joint?
Products from Arbo and Everbuild, among others, chosen to suit the joint. We explain the product when we quote.
Do you hold any approvals?
Yes. We hold ARBOMaster approved applicator status and we are fully insured too.
Can tenants book the work?
Yes. Ask your landlord first, and we can send them the quote if that helps.
Do I need permission for sand mastic on a listed building?
It’s best to ask your local planning authority first. Like-for-like sand mastic is often the preferred finish but the decision is theirs.
Do I need to be at home?
Access is agreed with you when the job is booked. For inside work, that normally means someone being in.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. We cover Thornhill and the rest of Dumfries and Galloway.
What sand mastic looks like in Thornhill
Sash and case windows are common in older Scottish homes, often pointed into the wall with traditional sand mastic. Under the Repairing Standard, private landlords in Scotland have to keep homes wind and watertight, and failed outside joints work against that.
Schools such as Wallace Hall Academy are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages. In and around Thornhill, as anywhere, good sand mastic starts with a clean, dry, properly prepared joint.
Thornhill is about 13 miles north-west of Dumfries, in Dumfries and Galloway. From the centre of Thornhill to the outskirts, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. Our area takes in 138 places across Dumfries and Galloway, from the larger towns to small villages. There’s also a page for Glasgow, roughly 47 miles from Thornhill.
We work across DG3 for sand mastic. That includes homes and businesses on Drumlanrig Street, West Morton Street and St Cuthbert's Walk. We also cover Keir Mill (2 miles south-west), Carronbridge (2 miles north), Penpont (2 miles west), Closeburn (2 miles south-east) and Wallaceton (5 miles south). Further out, we also cover Dumfries (13 miles south-east), Moffat (14 miles north-east), Heathhall (13 miles south-east), Newbridge Drive (12 miles south-east), Lochmaben (15 miles south-east) and Troqueer (14 miles south-east).
Landmarks near Thornhill
Other landmarks nearby include Morton Castle (2.5 miles north) and Thornhill Hospital (under half a mile south). Open spaces near Thornhill include Bellstane Loch.
Why it’s worth doing now in Thornhill
Filling over old, loose mastic doesn’t last. We remove the loose material first so the new mastic stays put. When the nearest tradesperson is a drive away, it’s tempting to leave a small leak, but water through a failed joint keeps working away until it’s fixed.
A few things move the cost up or down: how much old sealant there is and how stubborn it is, any mould to treat, and whether we need extra access for height. Your quote takes all of that into account.
Why choose Mr Mastic in Thornhill
- Fully insured
- Over 20 years’ experience
- Sanitary silicone with an anti-fungal additive in wet areas
- An ARBOMaster approved applicator
Take a look at our cost guide or our reviews.
The process
A visit follows a simple pattern: we look at the joints together, mask and protect the surrounding surfaces, do the work and tidy away. It usually takes a few hours per window, depending on the condition of the joints. For a place like Thornhill, longer drives are planned in advance. Mention tracks, gates, ferries or anything else about the route.
- We check the window surrounds and agree which joints need renewing.
- 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.
- The mastic is mixed, pressed into the joint by hand and shaped.
- The finish is dressed so it sits neatly against the stone or brick.
How to prepare
- Tell us if parking is tricky
- Let us know if you’ve seen damp or leaks
- Move anything stored near the joints
How to get a quote
To get a quote, send an email to info@mrmastic.co.uk with the location and a short description of the problem. We’ll give you a clear quote before any work starts.
Read more
DIY versus a professional finish
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, then guaranteed for a year.
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.