I scratch built this HO scale Tar Paper Shack by wrapping bits of black construction paper around a rectangle shaped box that I fashioned from cardboard. I don’t remember adding any strip wood for interior support. I just made sure the rectangles sides were square around a fitted cardboard floor. After the glue had dried I added the construction paper in scale strips that were cut to either three or four foot widths and painted these using Floquil grimy black and then added some dry-brushing. The door was constructed out of cardboard.