Exterior, House Building Type, Wood Siding Material, Concrete Siding Material, and Flat RoofLine The courtyard is just one of many open spaces that will be highly utilized—in the non-winter months anyway. Concrete worked well with developing the language of FlatPak. The second level is a wood panel that can be clad in corrugated metal or cedar—different layers that can be plugged in like covers on your cellphone.  Best Photos from How to Play FlatPak