https://dev.to/kittendigger2/c....at-flap-installation
Professionals should handle the installation of a cat flap on your door panel. The doors are typically made of a thin plastic exterior that is attached to an insulation-enhancing, soft polystyrene base. It isn't easy to cut through these materials. It's a lot easier to put the cat flap inside an existing pane of glass, or have a new door manufactured with the hole already prepared. A glazier is able to do this for you. Easy to Fit If you have a cat and you want to let them in and out without leaving