Hampshire · England
Window & door mastic in Keyhaven, Hampshire
Mastic around window and door frames, sills and patio doors for Keyhaven, backed by a 12-month guarantee. Ask us for a quote.
- Gaps where the sill meets the wall
- Draughty joints inside around the window
- Cold air getting in at the frame edge
What we’re called out for in Keyhaven
Timber windows bring their own problems. Old mastic gets painted over and cracks under the paint, and the wood moves with damp as well as heat.
Look out for any of the following:
- Leaking joints at the ends of sills
- Cracked or shrunken mastic around the frame
- Rain getting in at the frame or under the sill
- Whistling draughts around closed windows
In the older streets around Church of All Saints, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
Before you book anyone
- What happens if the job turns out different
- What preparation is included
- Who turns up on the day
- What insurance they hold
Window mastic in Keyhaven, done properly
Around Keyhaven we seal all kinds of frames: from uPVC casements to timber and aluminium, plus patio doors, French doors and sills. Each gets a sealant chosen for the frame and the wall it meets. We work on uPVC windows, window sills and composite doors, and people most often call us about cold air getting in at the frame edge and old mastic that has gone black or come away.
Homes in small places like Keyhaven often stand in the open, with little to shelter their windows from wind and rain. That exposure dries out and cracks the mastic around frames and sills faster.
You get a 12-month guarantee, the same in Keyhaven as everywhere else we work.
- Place
- Keyhaven (SO41)
- Wider area
- Hampshire
- Guarantee
- 12 months on all our work
- Quote
- Quoted before any work starts
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
How it works
When we arrive, we look over the joints with you first. We protect the surfaces around the joints before any work starts. Most jobs take a morning for a couple of windows and a door. Somewhere as small as Keyhaven, access is often the only tricky part. If the job is outside, mention outbuildings, exposed walls and how to reach them.
- We check each frame and agree which ones need doing.
- The old mastic is cut out and the surfaces cleaned back.
- We fit backing rod in deep gaps so the sealant is the right depth.
- We apply a weatherproof sealant to match the frame and tool it neatly.
- We clear up and check every joint is fully closed.
Preparing for the visit
- Clear items away from the joints we’re working on
- Keep children and pets away from the work area
- Let us know about earlier repairs to the joints
How to get a quote
A good description makes for an accurate quote. Let us know the location, the problem and roughly how many joints, and add photos by email if you can.
Advice
Keyhaven questions
Is Keyhaven within the area you cover?
Yes, we do. Our work covers 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 window mastic in a coastal place like Keyhaven any different?
Near the sea, outside joints face more wind, rain and salt than they would inland, so the choice of sealant and the preparation matter even more. Walls facing the sea are usually the first to need attention.
Will resealing my frames help with draughts?
It will if the frame joint is the problem. We check where the draught is before work begins.
When is the sealant fully cured?
Most sealants are touch-dry well before they’re fully cured. We will give you the cure time for the product we used.
Do you remove the old sealant?
Always. Sealing over the old bead is the commonest cause of early failure, so we never do it.
I rent my home. Can I book you?
We can work for tenants, landlords or agents. Get your landlord’s agreement first.
Is it messy?
We keep the work tidy. Nearby surfaces are protected, and the area is left clean when we finish.
Where is Mr Mastic based?
We are based in Crawley, and we work across South East England, London and Scotland.
How to look after the new joints
How long the joints last depends on use and care. We suggest:
- Wipe condensation off the frames
- Don’t aim a pressure washer at the joints
- Keep paint and stain on wooden frames in good order
- Do not use solvent cleaners on the joint
On timber frames, keep the paintwork in good order, since wood that gets wet swells and shrinks more. Paint up to the joint, not over the silicone.
Water gets in quietly when mastic fails. Often the first sign is a damp patch inside or flaking paint on the reveal. Early resealing stops it reaching that point.
Keyhaven homes and the weather
Keyhaven is within about 1 mile of the coast, where wind-driven rain is a fact of life and, nearer the shore, so is salt air. That’s hard on the mastic around window and door frames, especially on the side facing the sea. The South East is one of 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 Milford-on-Sea Church of England Primary School, its window and door frames need their mastic kept sound, just like a home’s. Letting a property close to Lymington Town station? Then sound mastic around windows and doors keeps out the draughts and damp that tenants notice first.
Keyhaven is about 3 miles south of Lymington, in Hampshire. We provide window mastic to homeowners, landlords and businesses in Keyhaven and the surrounding area, as part of our work across Hampshire. Our Hampshire coverage runs to 683 places, Keyhaven among them. You can also see our page for Southampton, about 16 miles away.
Here we cover the SO41 postcode area for window mastic. If you need window mastic at a property on New Road, Keyhaven Road and Saltgrass Lane or anywhere close by, our applicators can take on the job. We also cover the places around Keyhaven: Milford on Sea (1 mile west), Lymore (1 mile north-west), Lower Pennington (1 mile north-east), Everton (2 miles north-west) and Pennington (2 miles north). Further out, we also cover Totton (14 miles north), Hythe (12 miles north-east), New Milton (4 miles north-west), Ringwood (13 miles north-west), Warsash (15 miles north-east) and Barton on Sea (4 miles west).
Local landmarks in Keyhaven
Around Keyhaven, our work takes us to homes and buildings near The Gun Public House and Priestlands School. For rail, the closest station is Lymington Town station, about 3 miles north-east. Well-known places in the area include St Barbe Museum and Art Gallery (2.8 miles north-east) and Yarmouth Castle (3.3 miles east). For a walk, there’s Milford on Sea LNR and Tennyson Down.
DIY sealant or a professional job?
Not every job suits DIY: work at height, external movement joints, fire-rated sealant and large areas call for the right materials, safe access and experience.
A DIY attempt does not rule out a professional job. We remove it and do the joint properly, so just mention it when you contact us.
When something else is needed
New sealant can’t fix everything, and we’d rather say so up front. It will not solve:
- Soft or decayed wood in the frame
- Faulty window hardware
- A door that needs adjusting, rehanging or new seals
If in doubt, ring 0345 464 0079 or drop us an email and we will say what we think.
Surfaces we seal
- Timber windows & doors
- Window sills
- Patio & French doors
- uPVC windows
- Composite doors
- Aluminium frames
How we quote for window mastic
Every job gets its own quote. These are the things that affect it:
- The number of rooms or windows
- Whether there’s mould to deal with
- The product the joint needs
- The old material and how stubborn it is
Some things make a job bigger or smaller: how much old sealant there is and how stubborn it is, any mould to treat, and whether we need extra access for height. Your quote takes all of that into account.
What we need to know
What to tell us when you ask for a quote:
- How many joints, rooms or windows are involved
- Any access issues, like height or stairs
- Photos by email, if that is easy
- If someone has resealed it before
Asking for a quote is easy: let us know what needs doing and where. Photos by email help us understand the job, and we’ll come back to you with a quote.
Nearby places to Keyhaven
Also in Keyhaven
Why deal with it now?
A cracked joint around a frame lets rain into the wall. Over time that can mean damp patches, damaged plaster and rotting timber. A reseal is a much smaller job. Around Keyhaven, older homes often have timber in their floors and frames, and water through a failed joint can rot timber if it’s left.
A failed joint rarely gets cheaper to fix by waiting, because water and mould keep working on it. If you are unsure, call 0345 464 0079 or email us and we will give you an honest view and a quote.
Why us?
- Domestic, commercial and hotel work
- Anti-fungal silicone where joints get wet
- Fully insured
- We leave the area clean and tidy
Read our cost guide or our reviews.