Cat flap hole in wall too big!

richmond155

Hi

I have a hole in a cavity wall - brick, cavity, breezeblock - made to fit a cat flap. The flap is on the inside wall and a 'tunnel' leads to the outside. The tunnel is plastic - its sold by the cat flap manufacturers.
Unfortunately, the hole is far to big. I can't screw the cat flap into the wall becasue there isn't enough wall to hold the screws.

We've attempted to glue the inside actual flap piece to the wall, using no more nails, but the cats still push the whole tunnel structure loose, and its not unusual to find it a protruding a foot or more into the room.

Any ideas how I make the hole smaller and get the tunnel and cat flap permanently fixed in place.

I was wondering about foam filler to fill the gap, and then glue the tunnel in place onto the foam. Could I use something like' no more nails' on foam filler? Would it stick to rigid plastic?

I'm not a DIYer - so something simple please!
Thanks

maninthestreet

Just how big is this hole in the wall? A few pictures may help.

Ruski

Expanding Foam will both fill the void around the tunnel AND fix/hold it in place.

Be careful thatyou don't put too much in tho... picture the film 'The Blob' if you over do it ;-)