Hampshire · England
Sand mastic for sash & case windows in Blackwater, Hampshire
Sand mastic across Blackwater and nearby, with old sealant always removed completely.
- Weathered mastic on the most exposed windows
- Gaps round a timber door in stone or brick
- Patchy fillers round a sash window
Surface by surface
Stone surrounds
Stone openings are rarely perfectly straight, so the gap is not the same all the way round. Sand mastic is shaped by hand to suit.
Period and listed homes
A traditional finish suits a period property, and sand mastic is one of them.
Sand mastic in Blackwater
A silicone bead around a sash window can look out of place and is not always the right material. Sand mastic gives a finish that matches the age of the house and we can swap the silicone for it. We work on timber door frames, tenement windows and period & listed homes, and people most often call us about open joints round the window box and patchy fillers round a sash window.
Houses in smaller places like Blackwater can stand more in the open than those in a built-up town, so exposed windows and doors face the weather head on. The mastic around frames on those walls tends to age faster.
Big or small, it’s backed by our 12-month guarantee in Blackwater and across Hampshire.
- Location
- Blackwater (GU17)
- Region
- Hampshire
- Cover
- One year on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
What sealant work can’t fix
It helps to know what we can’t do too:
- Putty and glazing repairs
- Damaged stone surrounds
- Decisions on consent for listed homes
If in doubt, phone 0345 464 0079 or email us and we will say what we think.
What we seal
- Period & listed homes
- Tenement windows
- Sash and case windows
- Timber door frames
- Brick reveals
- Stone surrounds
How it works
On the day, there’s very little for you to do. Point us to the joints and we will get on with it. The job generally takes a few hours for a single window, longer for several. For a job in Blackwater, we agree the time, the access and parking before the day. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- We check each window surround and the condition of the joint.
- The joint is raked out and cleaned.
- We fill deep gaps so the new mastic isn’t too thick.
- We point the joint with sand mastic by hand.
- We finish the mastic to a tidy line.
Preparing for the visit
- Move anything stored near the joints
- Mention any parking rules near the property
- Where the joints are inside, avoid wetting them before we arrive
Getting a quote
Quotes start with a quick conversation. Describe the problem, the location and the size of the job, and we will explain how we’d tackle it. When it suits you, phone 0345 464 0079 or send us an email.
Read more
What else we do in Blackwater
Why it’s worth doing now in Blackwater
Silicone might seem the quicker option, but on period stone or brick it often looks out of place. Sand mastic suits the building and blends with the stone or brick. Homes in smaller places like Blackwater can face more weather, and failed outside joints let damp into walls. Indoors, a failed seal lets water into floors and panels as it would anywhere.
The cost depends on the size of the job, how much old material has to come out and how easy the joints are to reach. You will have a clear quote before any work starts.
What you get with us
- Anti-fungal sanitary silicone in wet areas
- 180+ five-star Google reviews
- Homes, businesses and hotels
- We never seal over old sealant
How to look after the new joints
No joint lasts for ever, but care makes a real difference. A few tips:
- Take care around the mastic when scraping paint
- Avoid patching sand mastic with silicone
- Clear gutters so water does not pour onto the windows
- Renew mastic before redecorating the windows
Check the mastic when you check the paintwork. Small cracks are easier to deal with early.
It’s best to renew mastic before painting the windows. Paint over cracked mastic only covers it up.
Blackwater: your questions answered
Do you cover smaller places like Blackwater?
Yes, Blackwater is covered. We work across London and the South East, and smaller places are part of that. The journey is planned ahead, so it helps to know about access.
Is Blackwater in your area for sand mastic?
Yes. Our work covers London and the South East, and Blackwater is part of that. Just call 0345 464 0079 or email us with a few details of the job, and we will give you a clear quote.
Will the old sealant be removed?
Yes. Sealing over old sealant is the main reason resealing fails early, so we never do it.
Are you ARBOMaster approved?
Yes. ARBOMaster is the approved applicator scheme for Arbo sealants, and we are part of it.
Can you do several jobs on one visit?
Yes. Just list everything you need and we will quote it together.
Is it possible to take out silicone and use sand mastic instead?
Often, yes. Once the silicone is out and the joint prepared we point it with sand mastic.
Is it worth trying it myself?
That depends on the joint. High-level, external movement and fire-rated joints are professional jobs.
I rent my home. Can I book you?
Yes. Ask your landlord first, and we can send them the quote if that helps.
Sand mastic in Blackwater: local notes
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.
In the older streets around St Barnabas Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame. If you look after a building such as Frogmore Infant School, larger buildings have plenty of frames, and the mastic around each one ages. If you let a flat or house near Blackwater station, any sash windows need sound mastic to keep draughts and rain out.
Blackwater is about 1 mile south of Sandhurst, in Hampshire. Blackwater gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Blackwater is one of 683 towns and villages in Hampshire where we work. We also work in Reading, around 11 miles away.
Work in GU17 works the same way as everywhere else we cover. You’ll find streets such as London Road, Bell Lane and Ash Close, and we cover them all. Other places close to Blackwater include Frogmore (1 mile west), Hawley (1 mile south-east), College Town (1 mile north-east), Sandhurst (1 mile north) and York Town (1 mile east). Larger places within reach include Basingstoke (14 miles west), Farnborough (3 miles south), Fleet (5 miles south-west), Aldershot (6 miles south), Alton (15 miles south-west) and Tadley (15 miles west).
Landmarks near Blackwater
In Blackwater, that means homes and buildings near Mr Bumble pub, Frogmore Community College and Royal Military Academy Library, among other places. For rail, the closest station is Blackwater station, about 0.6 miles east of the centre. A little further out are Frimley Park Hospital (2.4 miles south-east) and Staff College Museum (1.9 miles east). Open spaces near Blackwater include Horseshoe Lake and Ball Hill.
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.
If you’ve already had a go yourself, that is fine. We cut it out and start again, so tell us about it when you ask for a quote.
Landlord and commercial work in Blackwater
Landlords and letting agents in Blackwater can book us as well as householders. Resealing between tenancies is a simple way to keep a property in good order before the next move-in.
A neglected joint can let water reach the structure, which matters even more when someone else lives there. Resealing at the right time is simple maintenance.