Arlanzon A40 24.25 ft. D x 20.08 ft. Log Cabin D.I.Y. building | Hud-1 EZ Buildings This building includes 400 sq. ft. of interior space and a 55 sq. ft. covered porch. The building is an excellent addition for a homeowner to use as a hobby room, workshop, home office, garden house, guest room, weekend getaway cabin or just some additional living space. This is the perfect building for the DIY and easy weekend project to add more usable space without the expense of a room addition expenses.