Isle of Wight · England
Sand mastic for sash & case windows in Cowes, Isle of Wight
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Cowes and across the Isle of Wight. Fully insured, ARBOMaster approved and guaranteed for a year.
- Open joints round the window box
- Old sand mastic that has cracked, crumbled or fallen out
- Draughts and rain around sash boxes
About our sand mastic in Cowes
Sand mastic skins over fairly quickly, but it takes longer to harden fully. Traditionally, sand mastic is left unpainted, so ask us before you decorate. We work on stone surrounds, brick reveals and sash and case windows, and common reasons people get in touch are silicone on a period window that looks wrong and open joints round the window box.
Around Cowes, many houses have gained conservatories, French doors or replacement windows over time. Every addition brings more joints, each wearing at its own pace. Leaks generally start at a sill, a frame head or a glazing joint.
A one-year guarantee comes as standard, so you are not left on your own once the job is done.
- Location
- Cowes (PO31)
- Wider area
- Isle of Wight
- Cover
- 12 months on all our work
- Price
- Quoted before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
Questions from Cowes
Is sand mastic in Cowes guaranteed?
All our work, in Cowes and everywhere else, comes with a 12-month guarantee. We are fully insured, and an ARBOMaster approved applicator.
Is sand mastic in a coastal place like Cowes any different?
Near the sea, outside joints face more wind, rain and salt than they would inland, so preparation and the right sealant matter all the more. Walls facing the sea are usually the first to need attention.
Do you come to Cowes?
Yes. We cover Cowes and the rest of the Isle of Wight, as part of our work across South East England, London and Scotland. To book, phone 0345 464 0079 or send us an email.
When will the new mastic be hard?
Not straight away. The skin forms first, and the full set comes later, and we will tell you what to expect.
Should I use sand mastic or silicone?
Sand mastic generally suits period timber windows best. On modern frames, we’d normally use a flexible sealant.
Do I need to be at home?
For indoor joints, yes, someone needs to let us in. Once we’ve agreed the job, you do not need to watch us work.
What do you put in the joint?
We choose the sealant for the joint, not the other way round. Movement, water and weather all affect the choice, and we will tell you what we are using.
Will the old sealant be removed?
Yes, every time. New sealant won’t bond properly to old, so any old material comes out before anything new goes in.
Places near Cowes
Also in Cowes
What affects the cost of sand mastic
The quote reflects the job in front of us. We take into account:
- How many areas need sealing
- How much there is to do
- Any mould that needs treating
- When we can work, for business premises
We do not show prices on the website, because each job is priced on what it involves. For a quick quote, please phone 0345 464 0079 or send us an email and we will talk you through it.
Asking for a quote
When you call or email, it’s useful to know:
- How we’d reach the joints
- The type of property
- Roughly how big the job is
- The address or postcode of the job
We do not publish a price list, because every job is different. Instead, we send you a clear quote for your job. To arrange one, call 0345 464 0079 or send us an email.
Signs you need sand mastic in Cowes
Previous repairs in cement or silicone often trap water or crack away. They don’t suit the joint and we normally remove them.
Keep an eye out for these signs:
- Wind and rain getting in round a sash window
- Mastic worn away on windows facing the weather
- Mastic round period door frames that has failed
- Gaps where the frame meets the masonry
For site and facilities teams at buildings such as Cowes Primary School, its window and door frames need their mastic kept sound, just like a home’s.
Comparing quotes
- What product goes in the joint
- What guarantee comes with the work
- What insurance they hold
- When the joint can take water or movement
What we can’t put right
We’d rather tell you now than do work that won’t last, so these are the limits:
- Cracked or broken glass
- Sash cords, weights and draught-proofing of the sashes
- Masonry that needs repairing
If in doubt, ring 0345 464 0079 or send us an email and we’ll say what we think before you book.
What we seal
- Sash and case windows
- Stone surrounds
- Tenement windows
- Period & listed homes
- Brick reveals
- Timber door frames
Why deal with it now?
A silicone bead can be quicker, but it can look wrong on a period surround. Sand mastic is the traditional material and blends with the stone or brick. Draughts from a gap round a frame, damp under a sill or water behind a bath panel all start small, and early is when they’re cheapest and quickest to sort.
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, whether mould needs treating, and whether the work is at height. Your quote takes all of that into account.
Why us?
- 20+ years of sealant experience
- Tidy, careful work
- We never seal over old sealant
- 12-month guarantee on every job
Surface by surface
Tenement and terrace windows
Tenements and terraces often have many sash windows with ageing mastic. We work on single windows or whole elevations.
Sash and case windows
A sash window’s box frame sits in the masonry opening. Sand mastic seals the joint round it.
How the visit works
We bring everything the job needs with us, so you don’t need to buy or prepare anything. Once we have agreed what’s being done, the area is protected and the work begins. It normally takes a few hours for a single window, longer for several. Parking in a town like Cowes is normally straightforward, but tell us if there’s a driveway or any restrictions, and let us know if the work is upstairs, in a flat or up high outside.
- First we agree which joints need doing.
- Old mastic and any loose material are raked out.
- Deep gaps are packed so the mastic sits at the right depth.
- We apply the mastic by hand and shape it.
- We dress the finish so it sits neatly against the masonry.
Preparing for the visit
- Plan for the work area to be out of bounds to pets and children
- Mention any tricky access
- Tell us about any water getting in
Getting a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and email photos if that’s easy.
Advice
Should I try it myself first?
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is matched to the joint and its conditions, and the work is guaranteed for a year.
If you do try it yourself, take your time over the preparation: take out all the old sealant, make sure the joint is clean and dry, and give it the full cure time. If it fails, we can still redo it.
Sand mastic in Cowes: local notes
Cowes is within about 2 miles of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. Both are hard on the mastic around older windows and doors, which can dry out and crack sooner where a building faces the weather. The South East is one of the drier parts of the UK, though outdoor sealant still has to go onto a dry joint, so the forecast decides the day.
Homes close to St. Faith's Church include some older properties, and the joint between an old wall and a newer frame is generally the first place rain gets in.
Cowes is about 8 miles south-west of Gosport, in the Isle of Wight. If you need sand mastic in Cowes, it’s easy to get a quote: please call 0345 464 0079 or drop us an email. We’re based in Crawley and cover the Isle of Wight. Cowes is one of 125 towns and villages in the Isle of Wight where we work. Our Portsmouth page covers work nearby (11 miles or so).
Postcode districts we cover here for sand mastic: PO31. Whether your property is on Church Road, Market Hill and High Street or anywhere close by, we can help. Cowes is on the A3020 and B3320, which makes it straightforward to reach. Neighbouring places we cover for sand mastic include Gurnard (1 mile west), Northwood (1 mile south), Rew Street (1 mile south-west), Noke Common (3 miles south) and Parkhurst (3 miles south). Within a short drive, we also cover Newport (4 miles south), Ryde (7 miles east), Sandown (10 miles south-east), Shanklin (10 miles south-east), Ventnor (12 miles south) and Oakfield (7 miles east). Cowes is one of the larger places we cover in the Isle of Wight. Remote and island addresses need a little more planning, so please mention your location when you call 0345 464 0079 or email us.
What’s near Cowes
Locally, jobs take us to homes and businesses close to The Painters Arms, Isle of Wight Studio School and Cowes Enterprise College, among other places. Nearby you will also find Isle of Wight Natural History Centre (0.5 miles south-west) and West Cowes Castle (0.7 miles north). For a walk, there’s Briddlesford Nature Reserve and Mill Hill.