My daughter needed a Purple Martin bird house for their property in TN. Downloaded free plans on line and reduced the size from 12 apartments to 8 since we have to mail this to TN. Plans were straight forward except where I made it more complicated by modifying the size. 3/4 pine sides, bottom and top. 1/4 plywood room dividers, and front/back walls. I cannot believe the printed requirements of these birds. They must have a pretty powerful union. They demanded even 6×6 rooms, and at least 1" foam insulation in the attic - seriously!