Hampshire · England
Window & door mastic in St Leonards, Hampshire
Mastic around window and door frames, sills and patio doors for homes and businesses in St Leonards and across Hampshire. ARBOMaster approved applicators, fully insured, with a one-year guarantee.
- Gaps left after new windows were fitted
- Mastic that’s falling out in pieces
- Gaps between the frame and the inside reveal
How the job changes by surface
Patio & French doors
Not every patio door leak is a mastic problem: blocked drain slots, worn brush seals and threshold details can let water in too. We check before we reseal.
Aluminium frames
Aluminium moves with heat, and the frames are often slimmer than uPVC. A tidy bead in anthracite grey, black or a matching colour keeps the clean look.
Window mastic for homes and businesses in St Leonards
Frames and walls don’t move together. Plastic and aluminium frames move with the temperature, while masonry stays fairly still. So the sealant has to stretch and recover, which is why we use a low-modulus product. If you have gaps where the sill meets the wall and untidy mastic left by window fitters, we can put it right, on patio & French doors, composite doors and aluminium frames alike.
Around St Leonards, conservatories, garden rooms and patio doors are often part of the house. Their glazing joints and frame seals are as much a part of the job as the windows, and any older timber or sash windows need a sealant that suits them.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we will sort it.
- Location
- St Leonards (BH24)
- Wider area
- Hampshire
- Cover
- A year, on every job
- Price
- A clear quote up front
- Call
- 0345 464 0079
- Updated
- 26 October 2026
Work for landlords, hotels and businesses
Letting agents and landlords in St Leonards can book us as well as homeowners. Resealing between tenancies keeps a property looking cared for before the next move-in.
In hotels, rooms out of use cost money, so we plan the work room by room around your bookings where we can. We’ve worked in hotels as well as homes and businesses.
What window mastic looks like in St Leonards
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.
Homes close to All Saints include some older properties, and the joint between an old wall and a newer frame is normally the first place rain gets in.
St Leonards is in Hampshire. Whether you are in the middle of St Leonards or further out, window mastic is available for homes and businesses alike, from flats and houses to offices and hotels. St Leonards is one of 683 towns and villages in Hampshire where we work. Southampton is on our list too, around 21 miles away.
All of BH24 is covered for window mastic, from the main roads to the quietest streets. That includes homes and businesses on Cedar Avenue, Birch Close and Malmesbury Road and the roads around them. If you’re just outside St Leonards, we cover Ashley Heath (1 mile north), St Ives (1 mile north-east), Matchams (1 mile south-east) and Avon Castle (2 miles east). Further out, we also cover Lymington (14 miles east), New Milton (10 miles south-east), Ringwood (3 miles north-east), Barton on Sea (10 miles south-east), Ashley (10 miles south-east) and Milford on Sea (13 miles south-east).
Local landmarks in St Leonards
In St Leonards, that means homes and buildings near Avon Heath Country Park and the streets around them. Other landmarks nearby include St Leonard's Hospital (0.9 miles south-west) and Stapehill Abbey (3.9 miles south-west). Open spaces near St Leonards include Linbrook Lake and Blashford Lakes.
Should I try it myself first?
Some sealant jobs are within reach of a careful DIYer, like a short, easy-to-reach 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: 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.
Keeping the joints in good condition
So the new joints stay in good condition:
- Look round the frames every year or so
- Keep timber frames painted
- Clear any debris from frame drain holes
- Keep solvents and bleach off the sealant
Wipe the frames with soapy water when you clean the windows, and avoid solvent cleaners on the sealant.
Water gets in quietly when mastic fails. You might not see it until plaster blows or a damp patch appears inside. Catching it early keeps the fix to a reseal.
What happens on the day
Good joint work is mostly preparation, and we do not rush it. Every joint is cleaned and dried before new material goes in. In total, it usually takes anything from an hour or two to a full day, depending on how many frames there are. For a job in St Leonards, we agree the time, the access and parking before the day. Outdoor jobs depend on a dry day, since sealant needs a dry surface.
- First, we go round the frames with you and agree the list.
- The old mastic is cut out and scraped back to clean surfaces.
- Deep gaps get closed-cell backing rod to set the depth.
- A flexible exterior sealant is applied in a colour to suit the frame.
- We tool each bead neatly and check every joint is closed.
Getting ready for the visit
- Mention any leaks or damp you’ve noticed
- Tell us if parking is tricky
- Let us know about earlier repairs to the joints
Getting a quote
Getting a quote is simple: let us know the job and the location. Photos by email help us understand the job.
Read more
Common problems we fix in St Leonards
Joint shape matters as much as the product. A thin smear across a wide gap has nothing to it, while a joint packed solid can’t stretch. That’s what backing rod is for.
Common reasons people contact us are:
- Rain getting in at the frame or under the sill
- Sealant in the wrong colour for the frame
- Whistling draughts around closed windows
- Cracked or shrunken mastic around the frame
If you look after a building such as St Ives Primary & Nursery School, larger buildings have plenty of frames, and the mastic around each one ages.
Comparing quotes
- Who does the work, and how experienced they are
- What happens if they find a problem under the old sealant
- Whether the sealant suits the joint
- How long to leave it before use
When it isn’t the sealant
New sealant can’t fix everything, and we’d rather say so up front. It won’t solve:
- Broken hinges, locks or handles
- Damp problems in the wall away from the window
- Draughts through the window seals rather than the frame
If in doubt, phone 0345 464 0079 or email us and we will say what we think.
Where we work in St Leonards
- Timber windows & doors
- Composite doors
- Window sills
- uPVC windows
- Aluminium frames
- Patio & French doors
Your questions about window mastic in St Leonards
Is window mastic in St Leonards guaranteed?
All our work, in St Leonards and everywhere else, comes with a 12-month guarantee. We’re fully insured, and an ARBOMaster approved applicator.
Do you cover smaller places like St Leonards?
Yes. St Leonards is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Let us know about access, parking and anything unusual about getting there when you book.
What do you put in the joint?
The product depends on the job: anti-fungal sanitary silicone in wet areas, and other sealants where joints move or face the weather. Brands we use include Arbo and Everbuild.
Can you match the sealant to my frames?
Yes, we choose a colour to suit the frame. Grey and black frames get grey or black sealant, and wood-effect frames normally suit brown.
Can resealing stop a draught around my window?
Often, yes. Air often gets in between the frame and the wall, and sealing the inside and outside joints closes that path.
Is it worth trying it myself?
You can, for simple jobs. The key is preparation: remove all the old material and work on a clean, dry joint. We can always put it right if it fails.
I rent my home. Can I book you?
We are happy to deal with the tenant, landlord or agent. Get your landlord’s agreement first.
Can you work on commercial sites?
Yes, regularly. We can plan bigger jobs in stages to suit the site.