I decided to try to build a Adobe type building yesterday, and to do it as simple but practical as possible, just to try it and see how much time it would take.
So I did, and I choose to use some left over foam board I had laying around that was more or less destined to go in the bin, but I managed to get a few walls and a roof together, I did however have to glue some parts together to make a section big enough to make a wall and the roof...
After just under 1½ hours of effective work (this do not include drying times) it was done. And I'm certain I can do it in just 1 hour apiece if I do a few of them at the same time, and use foam board thats large enough to start with.
And here are some photos of them with a few Imperial Guard soldiers to give you a scale.
It is large enough to fit at least 9 miniatures on 25mm round bases on the roof, you could probably get another one or two in there if you really tried.