West Sussex · England
Sand mastic for sash & case windows in Southbourne, West Sussex
Traditional burnt sand mastic around sash and case windows and doors in stone and brick for homes and businesses in Southbourne and across West Sussex. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Open joints round the window box
- Old sand mastic that has cracked, crumbled or fallen out
- Gaps round a timber door in stone or brick
What the job involves on each surface
Tenement and terrace windows
Tenements and terraces often have many sash windows with ageing mastic. We can do one window or several.
Sash and case windows
A sash window’s box frame sits in the masonry opening. The gap round it is pointed with sand mastic.
How we handle sand mastic in Southbourne
Old sand mastic cracks, crumbles and falls out over time and gaps open up round the frame. We rake it out and renew it and tidies the surround. If you are dealing with patchy fillers round a sash window and gaps round a timber door in stone or brick, we can put it right, on timber door frames, sash and case windows and tenement windows alike.
In smaller places like Southbourne, homes range from older cottages to newer houses, with windows to match: timber, uPVC and aluminium. The right sealant depends on the frame and on what it sits in.
Big or small, you get the same one-year guarantee.
- Place
- Southbourne (PO10)
- Region
- West Sussex
- Guarantee
- A year, on every job
- Price
- A clear quote up front
- Telephone
- 0345 464 0079
- Last updated
- 26 October 2026
Also near Southbourne
Also in Southbourne
The process
You do not need to clear the whole room or building, only the area right around the joints. We protect the rest, and the work takes anything from a few hours to a full day, depending on how many windows in most cases. In a smaller place like Southbourne, parking is seldom the issue; lanes, gates and long drives are worth mentioning. If the job is outside, tell us about side access and how high the joints are.
- Each surround is checked first.
- The joint is raked out and cleaned.
- Large voids are packed out.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Keep children and pets away from the work area
- On commercial sites, let us know about site rules
- Mention if the joints have been sealed before
Ask for a quote
Every job is quoted individually. Just ring 0345 464 0079 or send us an email with the details and send pictures if you have them.
Read more
How to look after the new joints
Simple care keeps the joints in good condition. We recommend:
- Make sure water runs off the sill
- Go gently near the mastic when preparing windows
- Ask a joiner to look at soft timber first
- Renew mastic before redecorating the windows
Don’t touch or press the mastic while it hardens. It forms a skin fairly soon but needs longer to fully harden.
Small cracks are a sign the mastic is ageing. It’s easier to renew it before it drops out.
Southbourne: your questions answered
Is sand mastic in a coastal place like Southbourne any different?
Coastal weather is harder on outside sealant: there’s more wind-driven rain and, closer to the shore, salt in the air. The right product, a clean joint and the right depth all help it cope.
I let a flat near Southbourne station. Can you help?
Yes, landlords and agents are among the people we work for. Just phone 0345 464 0079 or email us with the address and what needs doing, and we will give you a clear quote.
Should I use sand mastic or silicone?
It depends on the window. Period windows in stone or brick normally suit sand mastic and newer frames generally get a flexible sealant.
Where is Mr Mastic based?
Mr Mastic is based in Crawley. We cover Southbourne and the rest of West Sussex, along with the rest of our area.
Can sand mastic be painted?
Traditional guidance is not to paint over sand mastic. Ask us before you decorate around it and we’ll advise.
Can you match the sealant colour?
Yes. Sealants come in white, clear, grey and other colours for many products, and we will agree it with you first.
Is consent needed for window work on a listed home?
Checking first is sensible. Your local planning authority can say if consent is needed for work on a listed home or in a conservation area.
Can you replace silicone on a period window with sand mastic?
Yes, we do this often. All the old silicone is removed first so the mastic beds in well.
Signs you need sand mastic in Southbourne
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.
The problems people normally mention when they call include:
- Patchy fillers round a sash window
- A silicone bead on a sash window that spoils the look
- Gaps where the frame meets the masonry
- Mastic round period door frames that has failed
Managing a site like Southbourne Junior School? Then larger buildings have plenty of frames, and the mastic around each one ages.
Questions to ask before booking
- Who turns up on the day
- How the joint is cleaned and prepared
- Whether you can choose the colour
- Whether VAT is included
When it isn’t the sealant
Some problems need a builder, plumber or other trade rather than us:
- Sashes that rattle, stick or will not open
- Crumbling stone or brickwork round the window
- Decisions on consent for listed homes
If you are not sure, just ring 0345 464 0079 or send us an email and we’ll give you a straight answer before you book.
Surfaces we seal
- Sash and case windows
- Timber door frames
- Tenement windows
- Period & listed homes
- Stone surrounds
- Brick reveals
Why act early in Southbourne
Draughts round a sash window aren’t always the sashes. Open mastic joints round the box can let air in, and renewing the mastic closes them. In an older home around Southbourne, damp from a failed joint can get into timber and plaster, which is far harder to put right than the sealant itself.
Combining jobs into one visit is generally more efficient than separate visits, so tell us about everything that needs sealing. We’ll give you a clear price for the lot.
Why choose Mr Mastic in Southbourne
- Rated 4.9 stars on Google
- Anti-fungal silicone where joints get wet
- Arbo and Everbuild products
- Fully insured
For landlords and businesses
Mouldy or split sealant often shows up at the end of a tenancy, and it’s easy to sort out between tenants. Several properties can go on one quote.
Hotels need rooms back in use, so the work can be planned room by room. Hotel work is part of what we do, alongside homes and businesses.
What sand mastic looks like in Southbourne
Southbourne is within about 1 mile of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. That is hard on the mastic around older windows and doors, especially on the side facing the sea. With historic houses such as Warblington Castle (about 2.5 miles west) nearby, there’s older building stock in the area around Southbourne 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.
Homes close to St. John's include some older properties, and the joint between an old wall and a newer frame is generally the first place rain gets in. Rented homes near Southbourne station change hands often, and older sash windows in a rental need their mastic kept sound to keep the weather out.
Southbourne is about 4 miles east of Havant, in West Sussex. Jobs in Southbourne get the same care as everywhere else we work: old sealant removed completely, careful preparation and a 12-month guarantee. Across West Sussex, we cover 371 places, Southbourne among them. For nearby work, see our Portsmouth page.
All of PO10 is within our area for sand mastic. If you need sand mastic at a property on Lodgebury Close, Manor Road and Northcote Gardens or a nearby road, we can help. Neighbouring places we cover for sand mastic include Woodmancote (1 mile north), Lumley (1 mile west), Westbourne (1 mile north-west), Emsworth (1 mile west) and Thorney Island (2 miles south-west). Further out, we also cover Bognor Regis (11 miles south-east), Chichester (6 miles east), Selsey (10 miles south-east), Portfield (6 miles east), Yapton (13 miles east) and East Wittering (6 miles south).
Landmarks near Southbourne
Typical jobs here are in homes near The Traveller's Joy Public House, Eames Farm and Bourne Community College, among other places. Southbourne has its own railway station: Southbourne station. Well-known places in the area include Warblington Castle (2.5 miles west) and Emsworth Museum (1.3 miles west). Open spaces near Southbourne include Stoke Down and Brook Meadow (Emsworth).