Cat Flap for a new Double Glazed Door - Good idea or Not?

12 Jan 2009
Reaction score
United Kingdom
I'm replacing my knackered old french doors with a new double glazed set and thinking of having a cat flap incorporated by the double glazers.

Is it a good idea or would it be best to find another place for the cat flap?

The new double glazed french doors are the pilkington k sort with gas in between - would a cat flap be a bad idea or cause other sorts of problems to the units?

If it doesn't make any difference are there any 4-way locking style cat flap products recomended as I will be supplying the flap myself.

I'm curious about how they are fitted and how the holes are cut and I've heard that only circular holes can be cut in glass - but most cat flap shapes have a square top with a rounded bottom. Has anyone had this done or are there any suppliers out there to advise as I don't know whether they are able to cut the hole exactly to size so it fits snugly or whether a larger shape is cut meaning there'd be gaps between the glass and the inside of the flap.

Thanks for all advice.
Sponsored Links
why not get the door made with all glass units and a spare so you can get them to fit the flap and have a spare to replace the flap if the cat dies or you move!!!
Cutting a hole in a pane of glass is one thing; making a hole in a sealed double glazing unit is quite a different feat, and probably not worth attempting. You may need to consider using a UPVC panel instead, which will be very easy to cut.

We've bought two 'Cat Mate' flaps through Ebay and been happy with them, if that's any help.

Be aware that a cat flap does compromise security to some extent. A while ago one of my sons came home to visit us. We were out; he caught one of the cats in the garden, offered its collar up to the flap and opened it using the magnet. This allowed him to get his arm inside and unlock the nightlatch. (We've altered our door security since then.) This isn't to give away any secrets: obviously, you don't actually need to catch the cat first, especially if you're prepared to break a plastic cat flap.

At least make sure you locate the flap far enough away from the handle and any other things you wouldn't want somebody to be able to reach.
the cat flap is to be added by the double glazers when making the new french door - I just wasn't sure whether having a cat flap added would compromise the affectiveness of the double glazing.
Sponsored Links
I’ve seen plenty of cat flaps installed into the lower fixed UVPC panels on doors & we’ve got one in our conservatory side door but I’ve never seen a cat flap installed in a glass panel before; are you sure they have said they can/will actually do that? To be honest I think a cat flap set in glass French doors is going to look awful, a cat tunnel through the wall may be a better option in this situation; a couple of folks on here seem to have them & I think Masona posted about his cat tunnel recently.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local