Hampshire · England
Sand mastic for sash & case windows in Southwick, Hampshire
Sand mastic across Southwick and nearby, with old sealant always removed completely and a 12-month guarantee.
- Window mastic to renew ahead of painting
- Old sand mastic that has cracked, crumbled or fallen out
- Wind and rain getting in round a sash window
Sand mastic for homes and businesses in Southwick
Fresh sand mastic forms a skin quite soon but full hardening takes longer. Traditional guidance is not to paint over it, so ask us before you decorate. Common call-outs are for mastic that needs renewing before redecorating and mastic round period door frames that has failed, across stone surrounds, tenement windows and sash and case windows.
In a village or hamlet like Southwick, older cottages and farmhouses often have timber windows set in stone or brick. Not every older frame suits a modern silicone bead, and sometimes a traditional sand mastic is the better choice.
You’re covered for a year from the day we finish. If anything is not right with it, call 0345 464 0079 or email us.
- Where
- Southwick (PO17)
- Wider area
- Hampshire
- Cover
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
How the visit works
The work is kept neat and contained to the joints we’re treating, so you can get on with your day. The job usually takes anything from a few hours to a full day, depending on how many windows, and we explain the cure time before we leave. In a small place like Southwick, access is normally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We start by checking each surround and agreeing the joints to renew.
- We rake out the old mastic and clean the joint.
- Large voids are packed out first, so the mastic is not too thick.
- 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
- Tell us if parking is tricky
- Let us know if you’ve seen damp or leaks
- Mention any tricky access
Getting a quote
For a quick quote, get us on the phone, or email us if that’s easier. Tell us about the joints that need doing and we’ll talk you through the work and give you a clear quote.
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Also near Southwick
More services for Southwick
For landlords and businesses
From a single let to a portfolio, the work is the same standard: the old material taken out, careful preparation and a 12-month guarantee.
We also work for property managers and facilities teams in Southwick and across Hampshire. We can quote a run of properties together, and we are fully insured.
DIY versus a professional finish
Not every job suits DIY: high-level joints, fire-rated gaps, external movement joints and big jobs need the right product, the right access and the right method.
If you’ve already had a go yourself, that’s fine. We cut it out and start again, so just mention it when you contact us.
FAQs for Southwick
Does living near the coast affect sand mastic in Southwick?
Near the coast, wind-driven rain and, nearer the shore, salt air make outside sealant work harder. The right product, a clean joint and the right depth all help it cope.
Can you help a landlord with a rental near Portchester station?
Yes, rental work is part of what we do. Just call 0345 464 0079 or send us an email and tell us about the property, and we will give you a clear price.
When will the new mastic be hard?
A skin forms quite soon, but full hardening takes longer. We will tell you what to expect for your job.
Can you match the sealant colour?
Most of the time, yes. We will tell you which colours the right product comes in.
Can old silicone round a sash window be swapped for sand mastic?
Generally, yes. Once the silicone is out and the joint prepared, sand mastic is applied by hand.
What guarantee comes with the work?
There’s a 12-month guarantee on every job.
What sealant do you use?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. We use products from Arbo and Everbuild.
Will you leave a mess?
We keep the work tidy. Nearby surfaces are protected.
What we’re called out for in Southwick
Over the years, sand mastic weathers. It hardens, cracks and starts to come away from the frame or the masonry.
It’s worth asking for a quote if you see:
- Old sand mastic that has cracked, crumbled or fallen out
- Mastic worn away on windows facing the weather
- Cement or filler used on old window joints that has cracked
- A silicone bead on a sash window that spoils the look
In the older streets around Church of St James Without the Priory Gate, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
What your quote should include
- Whether they’re fully insured
- What guarantee comes with the work
- How long to leave it before use
- What product goes in the joint
Southwick homes and the weather
Southwick 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. London and the South East are among the drier parts of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
If you look after a building such as King Richard School, the mastic around its windows and doors needs looking after like any other building’s. For landlords with property near Portchester station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
Southwick is about 3 miles west of Purbrook, in Hampshire. Wherever you are in the PO17 postcode area, we can carry out sand mastic at your property. We cover 683 towns and villages across Hampshire, large and small.
We work across the PO17 postcode area for sand mastic. Streets in the area include High Street, North Road West and Castle Road. We also cover Boarhunt (1 mile west), North Boarhunt (2 miles north-west), Portchester (2 miles south), Hundred Acres (3 miles north-west) and North Fareham (3 miles west). We also work in nearby towns such as Gosport (5 miles south), Havant (5 miles east), Eastleigh (12 miles north-west), Fareham (4 miles west), Horndean (5 miles north-east) and Chandler's Ford (14 miles north-west).
Around Southwick
We work in homes and buildings around Red Lion Inn, among other places. The closest station to Southwick is Portchester station, about 1.9 miles south of the centre. Other landmarks nearby include Portchester Castle (2.6 miles south) and Fareham Shopping Centre (3.2 miles south-west). Open spaces near Southwick include Portsdown Hill and St Clair's Meadow.
What happens if it’s left?
Cement-based fillers and modern sealants do not always suit a period surround. Sand mastic is the like-for-like choice, which can matter on listed and conservation-area homes. Where a wall is exposed, as many are in small places like Southwick, wind-driven rain gets into any failed joint, and damp in older walls is slow to dry out.
Homes and businesses are quoted the same way: how much there is to do, how we reach it and what it needs, plus any working-time requirements on site. Call for a quick quote and we’ll explain what it covers.
Why choose Mr Mastic in Southwick
- An ARBOMaster approved applicator
- Homes, businesses and hotels
- We’re fully insured
- Old sealant always removed completely
Take a look at our cost guide and our reviews.
Different surfaces, different methods
Tenement and terrace windows
Where a building is shared, window work may involve neighbours, so check who is responsible first.
Sash and case windows
Sash windows are where we do most sand mastic work. Each joint round the box is raked out and renewed.
Quotes for sand mastic in Southwick
The price is agreed before any work begins. It takes into account:
- The size of the job
- Any working-time requirements on site
- Any mould that needs treating
- How easy the joints are to reach
No two jobs are quite the same, so each one gets its own quote. Size, access and the product the joint needs all play a part.
What we need to know
When you call or email, these details help:
- A few pictures by email, if you can
- Whether it has been sealed before
- The type of property
- What’s wrong with the joints now
For sand mastic in Southwick, ring 0345 464 0079 or email us. A short description of the job and where it is helps us quote, and we will agree the price before any work begins.