As the tabletop wargaming crafters on youtube will tell you; start with carton. Why not, it’s cheap or free and easy to use.
But not if you want to put it outside. Yes, we tried. With a lot of special coating for boats, we had some builds outside in the summer. Under some roofing that is, because we did not trust the rain.
So, the next best thing; XPS Styrodur foam. Already waterresistent by itself, it is used as house isolation on the outside.
Well, if that works, it should work for us as well.
But we need more than that. We need windows and roofs. And details like trees and grass. and figures.
Starting with the windows. We have tried now wood, foam and tooth sticks. We don’t know the results from the outside tests still, but all looks good so far.
As for the roofs; the first was just xps foam cut, but for the second we wanted a ‘thatched’ looking roof. We found hemp to work best.
Working with elmers glue (the type that is used for book binding in CZ) it makes a realistic thatched roof.
For paint we use the cheapest hobby waterbased paint, sometimes mixed with Balakril waterbased house paint, finished with a also waterbased Balakril external wood laque.
So far, so good.