Portsmouth · England
Landport Window Mastic
Window and door frames in Landport need attention? We cut out the old, prepare the joints and apply the right sealant, and the work is guaranteed for a year.
- Untidy mastic left by window fitters
- Cracked or shrunken mastic around the frame
- Sealant in the wrong colour for the frame
Can I do it myself?
The biggest DIY mistake is sealing over old sealant. Silicone does not stick to old silicone, so it lifts and traps water and mould underneath. Everything old must be removed first.
A DIY attempt doesn’t rule out a professional job. We remove it and do the joint properly, so tell us about it when you ask for a quote.
Window mastic for homes and businesses in Landport
Some gaps around frames are far deeper than they look. Filling it with sealant alone leaves a joint that can’t move properly, so we fit backing rod to set the right depth. The sealant then grips the two sides it should. We work on timber windows & doors, window sills and composite doors, and common reasons people get in touch are draughts coming in around windows and doors and rushed sealant from a window installation.
Houses in smaller places like Landport can stand more in the open than those in a built-up town, so exposed windows and doors face the weather head on. That’s hard on the mastic around frames and sills.
We guarantee the work for a year. If something is not right with it in that time, tell us and we’ll put it right.
- Location
- Landport (PO1, PO2, PO5)
- Region
- Portsmouth
- Cover
- One year on every job
- Quote
- A clear price before any work starts
- Telephone
- 0345 464 0079
- Page updated
- 26 October 2026
How the visit works
Most of a good job is in the preparation, so that’s where we spend the time. Joints are cleaned back and dried before anything new goes in. All told, the work takes a morning for a couple of windows and a door. A visit to Landport is planned like any other: the time, the access and where to park are agreed in advance. If the work is outside, the weather plays a part, as sealant needs a dry surface.
- We check how each frame can be reached safely.
- All the failed sealant is cut away.
- The surfaces are cleaned and left dry, and primed where the sealant calls for it.
- Backing rod fills deep voids and the sealant goes in on top.
- We tool the joint so water runs off, then clear up.
Before we arrive
- Mention any parking rules near the property
- Let us know about earlier repairs to the joints
- Let us know if you’ve seen damp or leaks
How to get a quote
For a quick quote, get us on the phone, or send an email if you’d rather. Tell us about the joints that need doing and we will explain what’s involved before giving you a price.
Related advice
Landport: your questions answered
Can you help a landlord with a rental near Portsmouth & Southsea station?
Yes, we work for letting agents and landlords. You can call 0345 464 0079 or drop us an email with the address and a few details, and we’ll give you a fixed price before work begins.
Will you come out to Landport?
Yes. Landport is within the area we cover, which takes in towns, villages and rural addresses. Our work covers London and the South East. Just mention lanes, gates or anything else about the route when you book.
Can resealing stop a draught around my window?
In many cases. The gap between frame and wall is a common source of draughts, and sealing the inside and outside joints closes that path.
Is there any odour?
Possibly a little. Any smell clears as the sealant cures.
Does someone need to be in?
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 match the sealant to my frames?
Yes. We can use white, brown, anthracite grey, black or clear, so the joint suits the frame.
Do you guarantee window mastic?
Yes, with our one-year guarantee. A yearly look at the joints helps them last.
Can you reach windows above the ground floor?
Normally, yes. We plan safe access before the job, so mention the height and anything in the way.
What happens if it’s left?
The work is quick compared with the damage it prevents: the visit takes a few hours for a few frames, or a day or more for a whole house. Wait for damp to appear and there may be plaster and decorating to sort out too. Homes in smaller places like Landport can face more weather, and failed outside joints let damp into walls. Inside, a split seal lets water into floors and panels just as it would anywhere.
Leaving a failed joint normally makes the job bigger, not smaller. If you are not sure whether it needs doing, ring 0345 464 0079 or email us for an honest opinion and a quote.
Why choose Mr Mastic in Landport
- White, clear, grey or another colour, product permitting
- Fully insured
- 12-month guarantee on every job
- 20+ years of sealant experience
What sealant work can’t fix
Before you book, it’s worth knowing the limits:
- A frame that has rotted at the joint
- Damp coming through the wall itself rather than the frame joint
- 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’ll give you a straight answer.
Joints and surfaces we work on
- Patio & French doors
- Composite doors
- Aluminium frames
- uPVC windows
- Timber windows & doors
- Window sills
Do you need window mastic in Landport?
Sun, frost and rain wear sealant out. UV light hardens the outside of the bead, until it loses its stretch and starts to crack.
Any of these means the joints need attention:
- Whistling draughts around closed windows
- Old mastic that has gone black or come away
- Hard, cracked sealant around windows
- Gaps where the sill meets the wall
If you live in an older home near Church of All Saints, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
What your quote should include
- When the joint can take water or movement
- Whether they seal over old material or remove it
- Which colour the sealant will be
- How hidden problems are handled
Window mastic in Landport: local notes
Landport 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. 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.
If you let a flat or house near Portsmouth & Southsea station, sound mastic around windows and doors keeps out the draughts and damp that tenants notice first. If you look after a building such as Ark Dickens Primary Academy, its window and door frames need their mastic kept sound, just like a home’s.
Landport is about 1 mile south-west of Portsmouth, in Portsmouth. Landport gets the same service as everywhere we cover: the old material taken out, joints prepared properly and a 12-month guarantee. Our Portsmouth coverage runs to 19 places, Landport among them.
We work across PO1, PO2 and PO5 for window mastic and the streets around it. If you need window mastic at a property on Lake Road, Watts Road and Alfred Road or anywhere close by, we can help. If you are just outside Landport, we cover Portsmouth (1 mile north-east), Fratton (1 mile east), Rudmore (1 mile north), Kingston (1 mile east) and North End (1 mile north). Further out, we also cover Wymering (3 miles north), Paulsgrove (3 miles north), Cosham (3 miles north), Drayton (3 miles north-east) and Farlington (4 miles north-east).
Around Landport
We work in homes and buildings around The Painters Arms, St Edmund's Catholic School and Alexandra Park and the streets around them. Landport has its own railway station: Portsmouth & Southsea station. Other landmarks nearby include Royal Portsmouth Hospital (under half a mile south-west) and Charles Dickens Birthplace Museum (within half a mile north). For a walk, there’s Milton Locks and Portsdown Hill.
Looking after it afterwards
To keep the joints looking good and working properly:
- Don’t paint over the silicone
- Wipe condensation off the frames
- Make sure the drainage slots are not blocked
- Wash the frames with mild soapy water
On timber frames, keep the paintwork in good order, since wood that gets wet swells and shrinks more. Keep paint off the silicone itself.
Water trapped behind a failed joint can start rot in timber frames and sills. Rotten timber needs a joiner, not a sealant, so it pays to reseal before that happens.
More services for Landport
Surface by surface
Composite doors
Draughts round the door leaf normally come from worn seals or adjustment, not the mastic. We will tell you if that is what we find.
Aluminium frames
Aluminium needs a sealant that bonds to coated metal. Neutral-cure sealant is the safe choice.