https://blogfreely.net/davideg....gnog36/cat-flap-inst
It is possible to install an apron flap inside the upvc panel, or even a double glazing sealed unit. The best solution is to put in an entirely new glass pane that has a pre-made hole. Take note of the instructions that will be included in the kit for cat flaps, and follow them closely. Make sure that the shape you have drawn (be it square or circle) is accurately depicted on your template drawing. Safety If you have a dog or cat and would like to let them in the garden without leaving the door open A microchip activate