West Sussex · England
Keynor Estate Window Mastic
Mastic around window and door frames, sills and patio doors for homes and businesses in Keynor Estate and across West Sussex. Fully insured, ARBOMaster approved and guaranteed for a year.
- Cracked internal joints between frame and plaster
- Damp patches on the reveal after heavy rain
- Hard, cracked sealant around windows
Surface by surface
uPVC windows
uPVC expands and contracts noticeably with temperature, so the joint needs a low-modulus sealant that stays flexible. White is the usual colour, with brown, anthracite grey and black for coloured frames.
Composite doors
An exposed front door gets wind-driven rain. We pay most attention there.
How we handle window mastic in Keynor Estate
A cold draught around a closed window often comes from the frame edge. Resealing that joint can make a room feel noticeably less draughty. If the draught is through the window seals instead, we’ll tell you. Common call-outs are for cracked sealant at the sill ends and old mastic that has gone black or come away, across composite doors, uPVC windows and aluminium frames.
In a village or hamlet like Keynor Estate, older cottages and farmhouses often have timber windows set in stone or brick. Not every older frame suits a modern silicone bead, so the sealant has to be chosen to suit the building.
A one-year guarantee comes as standard.
- Location
- Keynor Estate (PO20)
- Wider area
- West Sussex
- Cover
- A year, on every job
- Quotes
- A clear quote up front
- Phone
- 0345 464 0079
- Page updated
- 26 October 2026
FAQs for Keynor Estate
Do you work for landlords with property near Chichester station?
Yes. We work for landlords and letting agents as well as homeowners. You can phone 0345 464 0079 or send us an email with the details for a clear quote.
Do you cover smaller places like Keynor Estate?
Yes, Keynor Estate is covered. We work across London and the South East, from towns to the smallest places. Longer journeys are simply planned in advance.
Is it messy?
Not at all. The area is protected while we work and cleaned up afterwards.
Will there be a smell?
It depends on the product. Some products have a noticeable smell, others very little.
Do you work for hotels and businesses?
Yes. We have worked for hotels, offices and other businesses, and we are fully insured.
How long will my window job take?
The work takes a few hours for a handful of frames, longer for a whole house. Access and how stubborn the old mastic is affect the time most.
Is it worth trying it myself?
That depends on the joint. High-level, external movement and fire-rated joints are professional jobs, while a short indoor joint may be within reach.
Can I add another job to the visit?
Yes. Tell us about everything you’d like done and we’ll quote it together.
Frames and glazing around Keynor Estate
Keynor Estate 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 window and door frames, 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.
If you live in an older home near St Mary Our Lady Sidlesham, frames set in older brick or stone need a sealant that suits the wall as well as the frame. For site and facilities teams at buildings such as Sidlesham Primary School, its window and door frames need their mastic kept sound, just like a home’s. Rented homes near Chichester station change hands often, and cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
Keynor Estate is about 2 miles north of Selsey, in West Sussex. Anywhere in PO20, we can carry out window mastic at your property. Our West Sussex coverage runs to 371 places, and Keynor Estate is one of them. Our Portsmouth page covers work nearby (13 miles or so).
Here we cover the PO20 postcode area for window mastic. If you need window mastic at a property on Chalk Lane and Cow Lane or a nearby road, we can help. We also cover the places around Keynor Estate: Sidlesham (1 mile north-east), Street End (1 mile north), Church Norton (2 miles south-east), Sidlesham Common (2 miles north) and Pagham (2 miles east). Further out, we also cover Bognor Regis (5 miles east), Chichester (5 miles north), Littlehampton (12 miles east), Emsworth (8 miles north-west), Rustington (13 miles east) and Angmering (14 miles east).
Local landmarks in Keynor Estate
Around Keynor Estate, our work takes us to homes and buildings near The Academy, among other places. The nearest railway station is Chichester station, about 4.4 miles north of the centre. Well-known places in the area include Selsey Lifeboat Museum (2.9 miles south) and St Richard's Hospital (5.2 miles north).
Why act early in Keynor Estate
Working on frames from a ladder with a sealant gun isn’t easy, especially on upper floors. A professional job is cut out properly, backed where needed and finished neatly, using a product chosen for the frame and wall. Older cottages and farmhouses around Keynor Estate can have timber floors and frames, where water from a failed joint can cause rot if it’s left.
Doing several joints on one visit is normally more efficient than separate visits, so tell us about everything that needs sealing. You’ll get one clear quote for the whole job.
Why choose Mr Mastic in Keynor Estate
- Neat joints and a tidy finish
- A sealant colour to suit the surroundings
- Full insurance on every job
- White, clear, grey or another colour, product permitting
How we quote for window mastic
There’s no set price list. The quote depends on:
- The number and length of the joints
- Any mould that needs treating
- When we can work, for business premises
- How many rooms, windows or areas are involved
Rather than a set price list, we look at what your job involves: how many joints, what’s in them now and how we reach them. You will know the price before we begin.
What we need to know
A few details help us give you an accurate quote. When you ask for a quote, tell us:
- The type of property
- The problem you’ve noticed
- Whether it has been sealed before
- How we’d reach the joints
We don’t publish a price list, as no two jobs are quite the same. Instead, your job gets its own clear quote. To get started, call 0345 464 0079 or email us.
When it is not the sealant
We won’t take on work that will not last, so these are the limits:
- A frame that has rotted at the joint
- Damp coming through the wall itself rather than the frame joint
- A failed sealed unit that has misted up
If you’re not sure, just ring 0345 464 0079 or email us and we will give you a straight answer.
What we seal
- Patio & French doors
- uPVC windows
- Composite doors
- Timber windows & doors
- Window sills
- Aluminium frames
Places near Keynor Estate
More services for Keynor Estate
What happens on the day
We keep the work tidy and contained to the area we’re working on. The job generally takes a few hours for a few frames, or a day or more for a whole house. In a small place like Keynor Estate, access is generally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- We start by checking each window and door with you.
- Next the failed sealant is cut away and the joint cleaned.
- We fit backing rod in deep gaps so the sealant is the right depth.
- A flexible, weatherproof sealant is applied in a colour to suit the frame.
- Every joint is checked before we leave.
Preparing for the visit
- Plan for the work area to be out of bounds to pets and children
- On commercial sites, let us know about site rules
- Move anything stored near the joints
Ask for a quote
For a quick quote, get us on the phone, or email us if that is easier. Describe what needs sealing and we will talk you through the work.
Advice
For landlords and businesses
Failed sealant is one of the commonest items on a check-out report. Several properties can go on one quote.
Housing providers, facilities teams and property managers book us too. We can quote a run of properties together, and we’re fully insured.
Should I try it myself first?
The difference is mostly in the preparation and the product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, then guaranteed for a year.
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.