https://sciencewiki.science/wi....ki/Adding_a_Cat_Flap
It is possible to put a cat flap in a door panel made of upvc, or a double glazing glass sealed units, although the best option is to purchase a brand new pane of glass with a premade hole installed. Take note of the instructions that will be included with your cat flap kit and follow them closely. Make sure that the drawing accurately represents the shape (circle or square). Safety If you have a dog or cat and want to let them into the garden without opening the door, a microchip-activated pet flap in your door pa