I have attributed this thread to TB members, but randgust made a lot of the input. The thread begins with a request for making Spanish style buildings with arches, porticos, porches, etc. Randgust had one of several techniques for this, but when the thread drifted, as some of them do, several different construction methods were discussed for all types of walls and roofs. Here are some photos of both prototype and model buildings. Additional search terms: tile floor arch strathmore board bristol balsa Sentra poly foam styrene ABS Volmer Vollmer Ratio Kibri foamcore cardboard corrugated tin
Here is dave n showing his technique for making these Spanish arches and other items as he builds the Modesto depot. This thread is a continuation or supplement to the earlier link posted above.