The medieval buildings you'll see below have seen a lot of use in my rpg's. I love running games in cities, so it's no wonder - and the campaign I'm just about to finish is Ptolus, a huge book having a complete urban setting for D&D 3E.
The buildings are built almost completely from cardboard + surface materials - that's same old filler powder/PVA glue mixture I've used in so many of my models.
This building was inspired by a building I saw in venice. I covered the piece with my favourite mixture (filler/pva) and used toothpicks and pieces of cardboard to create some structure to it before it dried. The roof is also made in similar way, and I've used balsa wood and a bit of wire in the model, in addition to thinner cardstock.
As you can see, back of the building is open and is divided into too parts. It contains my smoke props, so any time there's smoke on the game table, this building is also there - even if not on the actual play area.
This second building has roof similar to the eariler one, it's bottom is made of foamcore and and top part balsa wood. Tile structure is cardstock glued on foamcore, I've created the structure by drawing them and pressing hard with the pen. Windows are transparent printed yellow and black mosquitoe net drybrushed with gold paint.
The other side - not much details here.
Top side off. The model is prepared on the inner side too, I might create a floor and some furniture for it one day.
Third buidling. Completely cardboard and cardstock except for window doors and borders and doors. I've applied dyed filler on the surface, but just enough to make it look alive, and then added some light-hued paints on it.
The model structure seen from below.
This is my first basic building. It's created from a box - just see the pic below to see it's bottom!
Details of the roof and the structure.