Allow your cat to go inside and out of your home without the cat flap. This allows your pet to move around freely and encourages exercise. It also reduces the risk of obesity and relieves boredom. Taskers can install cat flaps on wooden or uPVC doors Some can also work https://cat-flap-in-upvc-door-pan85418.ltfblog.com/29947527/cat-flap-double-glazing