I have a detached house with a single story exension at the back of my house. I am thinking of building a cat enclosure in the L shaped bit of my house for my three cats (currently house cats). Has anyone else done this I can't just let my tabby cat she was chucked out when she got pregnant and really wants to go out but the big outdoors frightens her so a cat pen would be a good alternative. Also they wouldn't bother anyone else by messing in their gardens. It would be 3 metres by 3 metres and roofed to prevent escapes.