Portsmouth · England
Southsea Sand Mastic
We cover Southsea for traditional burnt sand mastic around sash and case windows and doors in stone and brick. Old material cut out, joints cleaned and sealed neatly.
- Failed mastic on an exposed elevation
- Cracked mastic round a front door frame
- Old sand mastic that has cracked, crumbled or fallen out
Sand mastic in Southsea, done properly
Traditional burnt sand mastic that sits naturally against stone and brick. It’s a good fit for period properties where a modern sealant bead would stand out. Typical jobs include tired mastic found when preparing windows for paint and draughty sash windows at the surround, on stone surrounds, sash and case windows and brick reveals.
In a town like Southsea, the windows on the most exposed side of a house take the brunt of the rain, so the mastic there tends to fail first. It’s worth looking at every frame, not just the one that leaks.
Big or small, it’s backed by our 12-month guarantee.
- Where
- Southsea (PO5, PO4, PO1)
- Region
- Portsmouth
- Cover
- 12 months on all our work
- Quotes
- A clear price before work begins
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Signs you need sand mastic in Southsea
Water gets into small cracks in the mastic and loosens it further. Windows facing the weather tend to go first.
People generally contact us after spotting one of these:
- Window mastic to renew ahead of painting
- A silicone bead on a sash window that spoils the look
- Draughts and rain around sash boxes
- Patchy fillers round a sash window
Homes close to St Margaret of Scotland include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
What to look for in a quote
- Which sealant they’ll use, and why
- What guarantee comes with the work
- What preparation is included
- Whether they’re fully insured
How the visit works
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 generally takes a few hours for a single window, longer for several. A visit in Southsea needs access to the work and a place to park close by. If the job is outside, mention gates, side access and anything above ground floor.
- We check the window surrounds and agree which joints need renewing.
- We rake out the old mastic and clean the joint.
- Large voids are packed out first, so the mastic is not too thick.
- Sand mastic is mixed and applied by hand, then shaped to the joint.
- The finish is dressed so it sits neatly against the stone or brick.
Getting ready for the visit
- Plan for the work area to be out of bounds to pets and children
- Mention any leaks or damp you’ve noticed
- Tell us if parking is tricky
How to get a quote
Asking for a quote is easy: let us know the job and the location. Photos by email help us understand the job.
Advice
Southsea: your questions answered
I let a flat near Fratton station. Can you help?
Yes, landlords and agents are among the people we work for. Just ring 0345 464 0079 or send us an email with the address and what needs doing, and we will give you a clear quote.
Is sand mastic in a coastal place like Southsea 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.
Does someone need to be in?
Access is agreed with you when the job is booked. Indoors, that generally means someone at home.
Can sand mastic be painted?
Traditional guidance is not to paint over sand mastic. Ask us before you decorate around it and we will talk you through it.
Can I add another job to the visit?
Of course. Doing several areas at once is normally more efficient, so mention them when you ask for a quote.
Do you do commercial work?
Yes. Hotels, offices and other businesses use us and we are fully insured.
Which products do you use?
Products from Arbo and Everbuild, among others, picked for each joint. We’ll tell you what we are using and why.
How long does sand mastic take?
Most jobs take anything from a few hours to a full day, depending on how many windows. Your quote will say how long we expect yours to take.
What affects the cost of sand mastic
There’s no set price list. The quote depends on:
- Any mould that needs treating
- Whether old sealant or filler has to be cut out
- Any working-time requirements on site
- The size of the job
Commercial jobs are quoted on the same basis as homes: the amount of work, the access and the products needed. Call for a quick quote and we will explain what it covers.
What to tell us for a quote
When you contact us, these details help:
- How many joints, rooms or windows are involved
- Pictures of the joints, sent by email
- Access, such as stairs, a lift or height
- The type of property
We don’t publish a price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To arrange one, phone 0345 464 0079 or send us an email.
Towns and villages near Southsea
What else we do in Southsea
Surface by surface
Stone surrounds
Old stone surrounds are often uneven, so the gap isn’t the same all the way round. We shape it by hand to follow the stone.
Brick reveals
Gaps between frame and brick let in rain and draughts. New mastic seals the gap.
Why deal with it now?
Not every filler suits an old window surround. Sand mastic is the like-for-like choice and that can be important for listed homes. Gaps in sealant and mould in the bead never get better on their own, and in a busy household in Southsea they spread with every shower and every downpour. Now is the easy time to put it right.
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you’re not sure whether it needs doing, ring 0345 464 0079 or drop us an email and we’ll give you an honest view and a quote.
Why us?
- An ARBOMaster approved applicator
- 20+ years of sealant experience
- Every job guaranteed for a year
- Anti-fungal silicone where joints get wet
DIY sealant or a professional job?
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
If you’re set on DIY, put the effort into preparation: remove every trace of old sealant, clean and dry the joint, and follow the product’s cure time. If it does not work out, we can still put it right.
How to look after the new joints
Once the sealant has cured, a few habits help it last:
- Ask a joiner to look at soft timber first
- Ask us before painting near the mastic
- Take care around the mastic when scraping paint
- Check with your local planning authority if your home is listed
Make sure water drains away from the window surround. Constant wetting wears the mastic faster.
Small cracks are a sign the mastic is ageing. It’s easier to renew it before it drops out.
Frames and glazing around Southsea
Southsea is within about 1 mile of the coast, and homes near the sea take more wind-driven rain, with salt in the air closer to the shore. Both are hard on the mastic around older windows and doors, which can dry out and crack sooner where a building faces the weather. Rainfall in the South East is lower than in much of the UK, but outside sealant still needs a dry, clean surface, so outdoor work is planned around the forecast.
Rented homes near Fratton station change hands often, and any sash windows need sound mastic to keep draughts and rain out. Managing a site like Craneswater Junior School? Then its window and door frames need their mastic kept sound, just like a home’s.
Southsea is about 2 miles south of Portsmouth, in Portsmouth. Across the PO5 area, we can carry out sand mastic at your property. We cover 19 towns and villages across Portsmouth.
Every address in PO5, PO4 and PO1 is covered for sand mastic, from the main roads to the quietest streets. That includes homes and businesses on Bath Road, Liss Road and Beach Road. Neighbouring places we cover for sand mastic include Milton (1 mile north-east), Fratton (1 mile north), Kingston (1 mile north), Landport (1 mile north-west) and Baffins (2 miles north). We also work in nearby towns such as Hilsea (3 miles north), Wymering (4 miles north), Paulsgrove (5 miles north), Cosham (4 miles north), Drayton (4 miles north) and Farlington (5 miles north).
Around Southsea
In Southsea, that means homes and buildings near The Festing pub, St Edmund's Catholic School and Mayville High School. For rail, the closest station is Fratton station, roughly 0.8 miles north of the centre. Nearby you’ll also find St. Mary's Hospital (1 mile north) and Southsea Castle (1 mile south-west). Open spaces near Southsea include Milton Locks.