Furnished content.
(from Lumberjocks.com)
A few years ago my customer modified a dog house so it could roll up to her cat door and provide a place outside the house for the kitty litter trays. It was beyond help so I built a new one. Bungie cords and locking casters keep it tight against the door. The hinged top provides easy access for cleaning out the litter trays. The top is clad with galvanized sheet metal to protect it from the rain.