Hampshire · England
Swanwick Sand Mastic
Sand mastic across Swanwick and nearby, with every bit of old sealant taken out first and a 12-month guarantee.
- Cement or filler used on old window joints that has cracked
- Mastic worn away on windows facing the weather
- Gaps between timber frames and stone or brick
About our sand mastic in Swanwick
If your home is listed or in a conservation area, check with your local planning authority if consent is needed before window work. Sand mastic is often favoured as a like-for-like material. We work on brick reveals, tenement windows and period & listed homes, and the jobs we see most are old cement repairs round a window that have failed and mastic that needs renewing before redecorating.
Outdoor sealant needs dry, clean surfaces, so work on frames around Swanwick is planned for dry weather. Tell us about access to every side of the house, including upper-floor windows.
The work is guaranteed for twelve months. If there’s a problem with our work within the year, let us know and we will sort it.
- Location
- Swanwick (SO31, PO15)
- Wider area
- Hampshire
- Cover
- One year on every job
- Quotes
- Quoted before any work starts
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
Swanwick: your questions answered
Does the coastal weather in Swanwick affect outside sealant?
Coastal homes put outside sealant through more weather than inland ones, so the choice of sealant and the preparation matter even more. It’s worth checking the walls that face the sea first.
I let a flat near Bursledon station. Can you help?
Yes. We work for landlords and letting agents as well as householders. You can ring 0345 464 0079 or drop us an email with the details for a clear quote.
Is the work guaranteed?
You get our one-year guarantee on every job.
Where is Mr Mastic based?
We work from Crawley. We cover Swanwick and the rest of Hampshire.
Can I choose the sealant colour?
In most cases you can choose. We will tell you which colours the right product comes in.
Will you leave a mess?
We keep the work tidy. We protect what’s around the joints, and the area is left clean when we finish.
Is it OK to seal over old sealant?
No. Fresh sealant does not stick to old sealant, and anything trapped underneath, including mould and water, stays there. It all has to come out first.
How long does sand mastic take to harden?
It skins over fairly quickly but takes longer to harden fully. We’ll tell you what to expect for your job.
What the job involves on each surface
Sash and case windows
The box of a sash and case window sits in the stone or brick opening. The gap round it is pointed with sand mastic.
Period and listed homes
Many older homes were built with sand mastic round the windows. On listed buildings, check with your planning authority first.
What we’re called out for in Swanwick
Over the years, sand mastic weathers. It dries out, cracks and loses its grip on the stone or timber.
It’s worth asking for a quote if you see:
- Old cement repairs round a window that have failed
- Weathered mastic on the most exposed windows
- Gaps between timber frames and stone or brick
- Mastic dropping out of the joint
If you let a flat or house near Bursledon station, cracked sand mastic around sash windows lets in the draughts tenants complain about.
Before you book anyone
- Who does the work, and how experienced they are
- Are they insured?
- Which colour the sealant will be
- How the surfaces are prepared before sealing
Sand mastic in Swanwick: local notes
Swanwick is close to 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. Compared with the north and west, the South East gets less rain, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind.
Managing a site like Sarisbury Church of England Junior School? Then larger buildings have plenty of frames, and the mastic around each one ages. In the older streets around Church of St Paul, replacement windows fitted into old openings often leave uneven gaps that need backing and a flexible joint.
Swanwick is about 2 miles south of Hedge End, in Hampshire. Whether you are in the middle of Swanwick or further out, we cover sand mastic for every kind of property, from flats and houses to offices and hotels. Across Hampshire, we cover 683 places, Swanwick among them.
Every address in SO31 and PO15 is within our area for sand mastic. Local streets include Walpole Lane, Ashby Mews and Swanwick Lane, and we cover them all. Other places close to Swanwick include Lower Swanwick (1 mile north-west), Sarisbury (1 mile south-east), Park Gate (1 mile south-east), Burridge (1 mile north-east) and Sarisbury Green (1 mile south). Larger places within reach include Winchester (12 miles north), Gosport (8 miles south-east), Havant (13 miles east), Eastleigh (6 miles north-west), Fareham (4 miles south-east) and Horndean (12 miles east).
Near you in Swanwick
In Swanwick, that means homes and buildings near The Old Ship Inn and Brookfield Community School and Language College. The nearest railway station is Bursledon station, about 0.8 miles west. Other landmarks nearby include Bursledon Brickworks Industrial Museum (under half a mile north) and St Andrew's Castle (2.4 miles south-west). For a walk, there’s Swanwick Lakes.
DIY versus a professional finish
A careful DIYer can reseal a simple joint, such as a straightforward joint indoors. Where it goes wrong is sealing over the old bead, working on a wet joint or overloading the gap.
If you’re set on DIY, put the effort into 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.
How to look after the new joints
No joint lasts for ever, but care makes a real difference. Our tips:
- Have rotten timber repaired before new mastic goes in
- Go gently near the mastic when preparing windows
- Don’t run silicone over sand mastic
- Check the mastic when you check the paintwork
Check the mastic when you check the paintwork. Small cracks are easier to deal with early.
Crumbling mastic lets rain into the joint. It can soak into the frame and the surrounding masonry, so renewing it early is worth it.
What we do, step by step
We keep the work tidy and contained to the joints we are treating, so you can carry on as normal. The job usually takes a few hours for a single window, longer for several, and we tell you how long to leave it before we go. Somewhere as small as Swanwick, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We look at the surrounds with you and agree the joints to renew.
- Old mastic and any loose material are raked out.
- Deep gaps are packed so the mastic sits at the right depth.
- The sand mastic is mixed and pressed into the joint by hand.
- We dress the finish so it sits neatly against the masonry.
Preparing for the visit
- Tell us about access, such as stairs, a lift or high-level joints
- On commercial sites, let us know about site rules
- Tell us about any previous sealing or DIY attempts
How to get a quote
For sand mastic in Swanwick, call 0345 464 0079 or send us an email. Tell us what the problem is and where, and we’ll agree the price before any work begins.
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When something else is needed
We won’t take on work that won’t last, so these are the limits:
- Decayed frames that need repair
- Planning or listed building consent (your local planning authority decides)
- Putty and glazing repairs
Not sure which it is? You can phone 0345 464 0079 or drop us an email and we will tell you honestly before you book.
Surfaces we seal
- Sash and case windows
- Period & listed homes
- Stone surrounds
- Brick reveals
- Tenement windows
- Timber door frames
What affects the cost of sand mastic
The quote reflects the job in front of us. We look at:
- Which sealant suits the joint
- Any mould that needs treating
- How easy the joints are to reach
- The size of the job
No two jobs are quite the same, so each one gets its own quote. Size, access and the product the joint needs all make a difference, and we’ll explain the quote if you ask.
What to tell us for a quote
Before you ask for a quote, have a think about:
- If someone has resealed it before
- How many joints, rooms or windows are involved
- Photos by email, if that is easy
- How we’d reach the joints
We don’t publish a price list. Instead, we give you a clear quote for your job. To get started, call 0345 464 0079 or email us.