My 2nd catio from wayfair , needed more room and this did the trick! I did modify a bit. Built a floor with 2x4s as I regretted not having one in previous catio. Helps to have 2 people when putting shelves in- 1 person inside to hold, 1 outside screwing in. Otherwise fairly easy. Once up against the house, the roof is difficult to screw on in the back. I will probably have to come up with something back there. Also used way more screws for the roof, as the shelves are close to the top. Overall my cats and I love it!