https://morphomics.science/wik....i/Using_uPVC_Cat_Fla
https://pediascape.science/wik....i/Cat_Flap_Installer
If you're looking for a method to let your pet in and out without having to worry about them leaving unwanted "gifts" in the house, then consider getting an upvc door panel that has a cat flap fitted. This option is less expensive than replacing the entire door, and is easier to put in. Although it is possible to put a cat flap in your own uPVC door, it's important to understand that this is a difficult job that could result in costly errors. Easy to install