Southampton · England
Sand mastic for sash & case windows in Thornhill, Southampton
Specialist sand mastic for Thornhill: the right sealant, proper preparation and a neat finish. Call for a quick quote.
- Mastic round period door frames that has failed
- Weathered mastic on the most exposed windows
- Patchy fillers round a sash window
Questions from Thornhill
Does the coastal weather in Thornhill affect outside sealant?
Near the coast, wind-driven rain and, nearer the shore, salt air make outside sealant work harder. Choosing the right sealant for the frame and wall, laid at the right depth, helps it last.
Will you come out to Thornhill?
Yes, we do. Our work covers London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Do the sealants smell?
It depends on the product. Some products have a noticeable smell, others very little.
Is it possible to take out silicone and use sand mastic instead?
Often, yes. Once the silicone is out and the joint prepared we point it with sand mastic.
Are you an approved applicator?
Yes. We’re approved under the ARBOMaster scheme, the approved applicator scheme for Arbo sealants.
Where do you work from?
We are a Crawley-based firm, with over 20 years’ experience. Our area covers South East England, London and Scotland.
Should I use sand mastic or silicone?
We will talk it through with you. Period homes often look best with sand mastic, and modern sealants suit newer frames.
Which products do you use?
Quality sealants from brands including Arbo and Everbuild, picked for each joint. We explain the product when we quote.
Sand mastic in Thornhill, done properly
We renew sand mastic around sash windows and doors in stone and brick. The old mastic is raked out, and new mastic is applied and shaped by hand. We work on brick reveals, stone surrounds and tenement windows, and the jobs we see most are mastic round period door frames that has failed and mastic that needs renewing before redecorating.
Around Thornhill, conservatories, garden rooms and patio doors are often part of the house. Those joints need the same attention as the main windows.
We stand behind the work with a 12-month guarantee, so you’re not left on your own once the job is done.
- Place
- Thornhill (SO19, SO18, SO30)
- Wider area
- Southampton
- Guarantee
- One year on every job
- Quotes
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
What affects the quote in Thornhill
Every job gets its own quote. These are the things that affect it:
- How many areas need sealing
- Any working-time requirements on site
- The size of the job
- Any mould that needs treating
Rather than a set price list, we price the job in front of us: how many joints, what’s in them now and how we reach them. The price is agreed before we begin.
Helping us quote
Photos by email are helpful but not essential. Try to tell us:
- Access, such as stairs, a lift or height
- How many joints, rooms or windows are involved
- Any previous sealing or DIY work
- The address or postcode of the job
Need a quote? Please phone 0345 464 0079 or email us and tell us about the job. We’ll explain what we’d do and send you a clear quote before we start.
Why deal with it now?
Cement-based fillers and modern sealants do not always suit a period surround. Sand mastic matches what was there, which can matter on listed and conservation-area homes. In a smaller place like Thornhill, wherever a wall is exposed, a failed outside joint is a real source of damp. Inside, a split seal lets water into floors and panels just as it would anywhere.
The cost depends on the size of the job, how hard the old material is to remove and access to the work. We give a clear quote before any work starts.
What you get with us
- Homes, businesses and hotels
- Over 20 years’ experience
- Neat joints and a tidy finish
- Rated 4.9 stars on Google
How the visit works
When we get to you, we check the joints match what you told us. If anything is different, we explain it before carrying on. After that, the work takes a few hours per window, depending on the condition of the joints. Parking around Thornhill is usually easier than in a town centre, but mention any lanes, gates or long drives. For outside work, side access and the height of the joints help us plan.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- 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 mastic is finished to sit tidily against the stone or brick.
Before we arrive
- Mention if the joints have been sealed before
- Keep children and pets away from the work area
- Try not to wet indoor joints just before the visit
How to get a quote
It all starts with a short chat. Describe the problem, the location and the size of the job, and we will talk you through what we’d do. When it suits you, ring 0345 464 0079 or drop us an email.
Related advice
Landlords, agents and businesses in Thornhill
Letting agents often deal with us directly. Tell us the address, the job and how access works.
We also work for property managers and facilities teams. Several sites can be quoted together, and we are fully insured.
Towns and villages near Thornhill
More services for Thornhill
How the job changes by surface
Brick reveals
Brick reveals round timber windows are often pointed with sand mastic. It suits older brickwork.
Sash and case windows
Sash windows are where we do most sand mastic work. We renew the mastic round each box.
Frames and glazing around Thornhill
Thornhill is within about 3 miles of 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. With historic houses such as South Stoneham House (about 2.4 miles north-west) nearby, there’s older building stock in the area around Thornhill as well as newer homes. Where a home is older, older frames set in brick or stone need a sealant that suits them, and sometimes that is traditional sand mastic.
Schools such as Thornhill Primary School are buildings too, and the mastic around its windows and doors needs looking after like any other building’s. For an older house near a landmark such as St Christopher, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Thornhill is about 2 miles east of Southampton, in Southampton. We carry out sand mastic for homes and businesses in Thornhill. Across Southampton, we cover 40 places, Thornhill among them.
We work across SO19, SO18 and SO30 for sand mastic and the streets around it. Sand mastic is available to properties on Drove Road, Barry Road and Luton Road and the roads around them. Being close to the A334, Thornhill is easy for our applicators to reach. Close by, we work in Harefield (1 mile north), Sholing (1 mile south-west), Bitterne (1 mile west), West End (1 mile north) and Chartwell Green (1 mile north). We also work in nearby towns such as Shirley (4 miles west), Regents Park (4 miles west), Maybush (5 miles west), Portswood (3 miles north-west), Coxford (5 miles west) and Freemantle (4 miles west). Thornhill is among the bigger towns we cover in Southampton.
What’s near Thornhill
In Thornhill, that means homes and buildings near Westwood Woodland Park, Woodlands Community College and Grove Park Business and Enterprise College. The closest station to Thornhill is Sholing station, about 1.4 miles south-west. Other landmarks nearby include Moorgreen Hospital (1.4 miles north-east) and Bitterne Local History Society Heritage And Research Centre (1.1 miles west). Open spaces near Thornhill include Netley Common.
What we cannot put right
Before you book, it’s worth knowing the limits:
- Decayed frames that need repair
- Masonry that needs repairing
- Broken panes
If you are not sure, just phone 0345 464 0079 or send us an email and we will give you a straight answer.
Where we work in Thornhill
- Tenement windows
- Brick reveals
- Timber door frames
- Sash and case windows
- Period & listed homes
- Stone surrounds
Do you need sand mastic in Thornhill?
Shallow joints are a common cause. Mastic that’s too thin cracks and drops out, which is why we pack deep voids first and get the depth right.
People normally contact us after spotting one of these:
- Old sand mastic that has cracked, crumbled or fallen out
- Cracked mastic round a front door frame
- Tired mastic found when preparing windows for paint
- Modern sealant on a period surround
Letting a property close to Sholing station? Then older sash windows in a rental need their mastic kept sound to keep the weather out.
What to look for in a quote
- What insurance they hold
- Is VAT in the price?
- Whether all the old sealant comes out first
- What happens if they find a problem under the old sealant