So I want to add an upstairs to the boys cage. It's a store bought ferplast something or other. Opens at the top and a small opening on the side. I want to give the boys more room and was wondering if anyone had any ideas of what material to use and how to add it. When I was young my dad and I made a loft for my Guinea Pig cage by using wood and attaching a ramp and putting the entire thing in using metal rods and zip ties. As I don't have access to power tools anymore I am not sure how to do this. Any advice would be appreciated!