Divide existing single uPVC window into 2 panels, one glass, one infill panel for cat flap

8 Mar 2022
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United Kingdom
I'd like to put a catflap into a tall, narrow double-glazed window (300mm x 1800mm), but the window isn't wide enough for a new glass panel with circular cutout for cat flap adapter.

The next best solution would be to divide the window into 2 panels. a 300mm x 300mm infill panel at the bottom and a 300mm x 1450mm glass panel at the top.

Is it possible to divide an existing window into 2 panes easily? I would need an extra bit of beading for the bottom of the lower pane and some kind of divider between the 2 panes to hide the join and keep the glass in place. Can't seem to find anything easily, so suspect it's not a diy job...

Catflap installers only seem to want to replace existing panels, not create new ones.

If not possible I'll get a new panel for the door next to the panel which is wide enough for a 300mm circular cutout, but the cat flap will be much more prominent once installed and higher off the floor than it needs to be.
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I think I need some king of muntin, ideally a upvc joining strip for 28mm glass, but can't seem to find anything like it online, only long aluminium ones...
I think you'll find it is a bit more complex than that. The mitre joints in the PVCu where the horizontal dividing bar will go will need to be induction welded (normally in a workshop as these welders are not really portable tools), and you will need to find the original manufacturer to match the PVCu profiiles. You'll also need to budget for a new set of glazing beads and a new DG unit. Do you know who the original manufacturer or installer was?

uPVC Glass Dividing Bar.jpg

This really is a far easier task to do with wooden frames!
Thanks JobAndKnock, I thought that might be the case.

Currently considering keeping all the existing beading and just using a 300 x 300 PVC panel below with a 300 x 1500 glass panel above, with a strip of black sticky sealant (came with a velux window) between and covered with a little bit of white trim.

Would the beading around 3 sides be enough to keep the glass in place? Not looking for a very long term solution as we'll prob replace the doors in a year or so, hence trying to cut costs.
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It isn't just glass - it's a double glazed (DG) unit, and they are quite heavy, not to mention expensive. Have you costed a new DG unit, yet?. TBH not a job I'd even consider doing
BTW cat flaps are often quite high off the ground externally anyway if there's a step down outside. They'll cope.
You can also make a hole in a wall.

This is more secure against burglars than a hole in a door or window.
A hole in a door or window can be used to manipulate a handle or lock to obtain entry

Some people like to leave their keys in the keyhole or on a hall table. These are also vulnerable. Glass in the door makes it easier for the intruder to see what he is doing.
Yep, about £40 for the PVC panel with hole cutout and £50 for the DG panel.

Been quoted minimum width glass for catflap is 335mm and that's for the small ones. There needs to be enough glass around the hole otherwise wont be as strong I guess.

The security concerns above are also valid. Without the divider someone could just kick the window at the join and it would probably all pop out. Hole in door and key could be reached from outside.

Will sort something out and post a photo when done.

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