Hampshire · England
Window Mastic in South Wonston
Mastic around window and door frames, sills and patio doors for homes and businesses in South Wonston and across Hampshire. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Mastic that’s falling out in pieces
- Gaps left after new windows were fitted
- Whistling draughts around closed windows
Window mastic in South Wonston, done properly
The mastic around a window or door seals the gap between the frame and the wall. When it cracks, hardens or pulls away, draughts and rain get in. The old mastic is removed and the joint resealed with a flexible exterior sealant. We are often asked to deal with cracked sealant at the sill ends and mastic that’s falling out in pieces, on aluminium frames, patio & French doors and timber windows & doors.
Somewhere as small as South Wonston, older homes often have timber frames set in stone or brickwork. Not every older frame suits a modern silicone bead, so the sealant has to be chosen to suit the building.
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.
- Place
- South Wonston (SO21)
- Region
- Hampshire
- Cover
- A year, on every job
- Price
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Common problems we fix in South Wonston
Mastic ages in the weather. UV light hardens the outside of the bead, and over the years it loses its give, cracks and comes away.
Look out for any of the following:
- Whistling draughts around closed windows
- Damp patches on the reveal after heavy rain
- Gaps between the frame and the inside reveal
- White mastic on grey or black frames
For landlords with property near Winchester station, renewing tired window mastic between tenants heads off draught and damp complaints.
Questions to ask before booking
- Whether all the old sealant comes out first
- Whether the sealant suits the joint
- Whether VAT is included
- How the joint is cleaned and prepared
Windows and doors in South Wonston
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.
Schools such as South Wonston Primary School are buildings too, and larger buildings have plenty of frames, and the mastic around each one ages. Homes close to St Margaret's include some older properties, and frames set in older brick or stone need a sealant that suits the wall as well as the frame.
South Wonston is about 4 miles north of Winchester, in Hampshire. Across the SO21 area, we can carry out window mastic at your property. Across Hampshire, we cover 683 places, South Wonston among them. Our Southampton page covers work nearby.
We cover every part of SO21 for window mastic and the streets around it. That includes homes and businesses on Norris Gardens, Wrights Way and Lovell Close. Other places close to South Wonston include Worthy Down (1 mile south), Springvale (2 miles south-east), Sutton Scotney (2 miles north), Stoke Charity (2 miles north-east) and Hunton (3 miles north). Within a short drive, we also cover Basingstoke (14 miles north-east), Winchester (4 miles south), Eastleigh (11 miles south), Andover (9 miles north-west), Chandler's Ford (10 miles south) and Alton (15 miles east).
Landmarks near South Wonston
The closest station to South Wonston is Winchester station, about 3.7 miles south. Well-known places in the area include Royal Hampshire County Hospital (4 miles south) and Winchester Castle (4.1 miles south). For a walk, there’s Winnall Moors.
How the visit works
We bring everything the job needs with us. After a quick look at the joints together, we protect the area and start. Most jobs take a few hours for a handful of frames, longer for a whole house. Somewhere as small as South Wonston, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We start by checking each window and door with you.
- Next the failed sealant is cut away and the joint cleaned.
- Deep gaps are filled with backing rod to set the depth.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Finally we tidy up and check each joint.
Preparing for the visit
- Let us know about earlier repairs to the joints
- Where the joints are inside, avoid wetting them before we arrive
- Keep children and pets away from the work area
Get a quote
We don’t publish a price list. Instead, we give you a clear quote for your job. To arrange one, call 0345 464 0079 or drop us an email.
Related advice
Honest limits
Some problems need a builder, plumber or other trade rather than us:
- A door that needs adjusting, rehanging or new seals
- A failed sealed unit that has misted up
- Penetrating damp from a failed cavity tray or render
Not sure which it is? You can phone 0345 464 0079 or drop us an email and we’ll tell you honestly.
Where we work in South Wonston
- Aluminium frames
- Window sills
- uPVC windows
- Composite doors
- Timber windows & doors
- Patio & French doors
South Wonston: your questions answered
I let a flat near Winchester station. Can you help?
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 quote.
Can you do window mastic in South Wonston?
Yes, South Wonston is within the area we cover. We work across London and the South East. You can ring 0345 464 0079 or send us an email and let us know what needs doing.
Do I have to be there?
We need access to the joints, so we will agree that with you when we book. For inside work, that normally means someone being in.
Can you get sealant to suit coloured frames?
Usually, yes. Tell us the frame colour when you get in touch and we will use the nearest match.
Can you seal over the old sealant?
No. New silicone won’t bond to old silicone, and it traps any mould or water underneath. It all has to come out first.
Is the new sealant paintable?
That depends on the product. Silicone is not paintable, but some hybrid sealants are. Mention any painting plans before work begins.
Will the old sealant be removed?
Yes. Sealing over old sealant is the main reason resealing fails early, and it’s something we never do.
How long before the joint can be used?
That depends on the sealant used, so please follow the time we give you when we finish.
Also near South Wonston
Also in South Wonston
Different surfaces, different methods
Aluminium frames
Metal frames expand in the sun and are often slim, with little room for error. A tidy bead in anthracite grey, black or a matching colour suits the frame.
uPVC windows
Plastic frames move a lot between a hot afternoon and a cold night, so we use a flexible, low-modulus sealant. White is the usual colour, with brown, anthracite grey and black for coloured frames.
DIY sealant or a professional job?
Some jobs are best left to a professional: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
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 doesn’t work out, we can still put it right.
For landlords and businesses
Whether it’s one flat or a portfolio, the work is the same standard: old sealant fully removed, joints prepared properly and a 12-month guarantee.
Water getting past a failed joint can damage the building, which is a bigger problem in a rented property. Keeping joints in good order is simple maintenance that we can handle for you.
What affects the cost of window mastic
We quote each job individually. This is what makes a difference:
- The size of the job
- Access and height
- How much old sealant there is and how hard it is to remove
- How many rooms, windows or areas are involved
Combining jobs into one visit usually makes better use of the time than several visits, so tell us about everything that needs sealing. We’ll send you a clear quote for the lot.
Helping us quote
When you contact us, it’s useful to know:
- A few photos by email, if you can
- Any previous sealing or DIY work
- The type of property
- How many joints, rooms or windows are involved
Asking for a quote is easy: tell us what needs doing and where and its rough size. A few photos by email make the job easier to understand, and we’ll come back to you with a quote.