Isle of Wight · England
Sandown Window Mastic
Window and door frames in Sandown need attention? We remove the old material, prepare the joints and seal them properly, with a one-year guarantee.
- Mastic that’s falling out in pieces
- Sealant in the wrong colour for the frame
- Rushed sealant from a window installation
Window mastic for homes and businesses in Sandown
Every window and door frame has a gap around it, and mastic is what closes it. Once that seal fails, wind and rain find the gap. Our applicators cut it out and replace it with a flexible, weatherproof sealant. We work on timber windows & doors, uPVC windows and aluminium frames, and common reasons people get in touch are hard, cracked sealant around windows and sealant in the wrong colour for the frame.
Many houses in smaller places like Sandown have conservatories, garden rooms or patio doors. Those joints need the same attention as the main windows.
Every job is covered by a one-year guarantee.
- Location
- Sandown (PO36, PO37)
- Region
- Isle of Wight
- Guarantee
- A year, on every job
- Quote
- Quoted before any work starts
- Call
- 0345 464 0079
- Page updated
- 26 October 2026
Landlord and commercial work in Sandown
We also work for property managers and facilities teams in Sandown and across the Isle of Wight. Several sites can be quoted together, and we are fully insured for the work.
Businesses can book us for washrooms, kitchens, offices and more. On commercial sites, working times can be discussed when we quote.
DIY sealant or a professional job?
Some sealant jobs are within reach of a careful DIYer, such as a straightforward joint indoors. The common mistakes are sealing over old sealant, sealing a damp joint and using far too much.
Overfilling a joint is a classic DIY mistake. A thick, smeared bead looks untidy and doesn’t move well, and the joint depth matters as much as the finish.
Aftercare tips
Aftercare is simple:
- Clean frames with a soft cloth and soapy water
- Paint up to the joint, not over it
- Wipe condensation off the frames
- Repaint timber before it’s bare
Silicone cannot normally be painted, so mention any painting plans before any work starts. We can use a paintable sealant where that matters.
A small gap around a frame only grows. As the old mastic shrinks further, more air gets through, and a cold room gets colder. A new joint closes it up.
Also in Sandown
Window mastic in Sandown: local notes
Sandown 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. Both are hard on the mastic around window and door frames, which can dry out and crack sooner where a building faces the weather. Historic houses like Morton Manor (about 1.5 miles north-east) are a reminder that the area around Sandown has older buildings as well as new. In older buildings, older frames set in brick or stone need a sealant that suits them, and sometimes that’s traditional sand mastic.
If you let a flat or house near Sandown station, cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets. If you look after a building such as The Bay Church of England School, larger buildings have plenty of frames, and the mastic around each one ages. Homes close to Christ Church include some older properties, and the windows may be timber, sash or later replacements, and each needs the right sealant against the wall.
Sandown is about 10 miles south of Gosport, in the Isle of Wight. If you need window mastic in Sandown, please ring 0345 464 0079 or send us an email for a quick quote. We cover the Isle of Wight from our Crawley base. Our the Isle of Wight coverage runs to 125 places, and Sandown is one of them. For nearby work, see our Portsmouth page (11 miles or so).
Postcode districts we cover here for window mastic: PO36 and PO37. That includes homes and businesses on High Street, Nunwell Street and Park Rise and the roads around them. With the A3055 and A3056 close by, Sandown is easy for our applicators to reach. Other places close to Sandown include Lake (1 mile south-west), Yaverland (1 mile north-east), Adgestone (1 mile north), Alverstone (1 mile north-west) and Morton (1 mile north-east). Further out, we also cover Newport (7 miles north-west), Ryde (5 miles north), Cowes (10 miles north-west), Ventnor (5 miles south-west), East Cowes (9 miles north-west) and Oakfield (5 miles north). As one of the bigger places in the Isle of Wight, Sandown has homes, rented property and businesses of every kind. Island and remote addresses take a little more planning, so please mention your location when you call 0345 464 0079 or send us an email.
Local landmarks in Sandown
Locally, jobs take us to homes and businesses close to The Old Comical pub, Sandown Bay Academy and Broadlea Primary School. Sandown has its own railway station: Sandown station. A little further out are National Poo Museum (under half a mile south) and Arthur Webster Memorial Hospital for Children (1.6 miles south-west). For a walk, there’s Alverstone Mead and Brading Down.
The process
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 few frames, or a day or more for a whole house. In a smaller place like Sandown, parking is seldom the issue; lanes, gates and long drives are worth mentioning. If the job is outside, tell us about side access and how high the joints are.
- We start by checking each window and door with you.
- The old mastic is cut out and the surfaces cleaned back.
- Where gaps are deep, backing rod goes in first.
- New exterior sealant goes on in a matching colour and is tooled smooth.
- Finally we tidy up and check each joint.
Before we arrive
- Try not to wet indoor joints just before the visit
- Clear items away from the joints we are working on
- Tell us about access, such as stairs, a lift or high-level joints
How to get a quote
Asking for a quote is easy: let us know the job and the location, and roughly how big it is. Photos by email help us understand the job, and we’ll come back to you with a quote.
Related advice
Honest limits
New sealant can’t fix everything, and we’d rather say so up front. Sealant won’t put right:
- Soft or decayed wood in the frame
- Worn gaskets, brush seals or a door that has dropped
- Misting between the panes of a double-glazed unit (that needs a new unit)
If you are not sure, just call 0345 464 0079 or drop us an email and we will give you a straight answer.
Surfaces we seal
- Composite doors
- Timber windows & doors
- Aluminium frames
- Window sills
- uPVC windows
- Patio & French doors
Why deal with it now?
Choosing the product is half the job. Interior caulk and bathroom silicone are not made for exterior frame joints. A low-modulus exterior sealant keeps its stretch through hot and cold weather. Homes in smaller places like Sandown 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.
Commercial jobs are quoted on the same basis as homes: how much there is to do, how we reach it and what it needs, plus any working-time requirements on site. Ask us for a quote and we will explain what it covers.
Why choose Mr Mastic in Sandown
- Tidy, careful work
- A sealant colour to suit the surroundings
- 4.9 on Google from 180+ five-star reviews
- 20+ years of sealant experience
Read what affects the cost and customer reviews.
What affects the quote in Sandown
Your quote is based on your job. We look at:
- Any working-time requirements on site
- Whether there’s mould to deal with
- The number and length of the joints
- The product the joint needs
What you pay reflects the work, not guesswork. That is why we ask about the job first.
Asking for a quote
Photos by email are helpful but not essential. Try to tell us:
- Roughly how big the job is
- How we’d reach the joints
- What the problem is, such as mould, gaps, leaks or cracking
- The type of property
Every job is quoted individually, so start by telling us what you need. Simply ring 0345 464 0079 or drop us an email and describe the job, and pictures are welcome.
Sandown: your questions answered
Do you cover smaller places like Sandown?
Yes, Sandown is covered. We work across London and the South East, from towns to the smallest places. The journey is planned ahead, so it helps to know about access.
Does the coastal weather in Sandown affect outside sealant?
Coastal homes put outside sealant through more weather than inland ones, so preparation and the right sealant matter all the more. It’s worth checking the walls that face the sea first.
Do I have to be there?
We need access to the joints, so we’ll agree that with you when we book. Indoors, that normally means someone at home.
Can I add another job to the visit?
Yes. Just list everything you need and we’ll quote it together.
Can you seal the gap between the frame and the plaster indoors?
Yes. The outside joint keeps the weather out, and the inside joint stops draughts and finishes the reveal. We do one or both.
Do you have sealant for grey or black windows?
Yes. We can use white, brown, anthracite grey, black or clear, so the joint suits the frame.
Do you work for letting agents?
Yes. As well as householders, we work for landlords, agents, businesses and hotels in Sandown.
Will resealing my frames help with draughts?
It will if the frame joint is the problem. We find where the air is coming from before we reseal.