Clifford Button of Paper Tiger Armanents offers a free 1/72 scale brick structure. It was inspired by a building in the Strand district in Galveston, Texas.
building
Modeling A Bombed Out Building
Here’s a tutorial / demonstration on making a nice looking bombed out building.
Urban Auto Electronics Shop Paper Model
This paper model is an appropriately grungy model of an auto electronics store.
Making Simple Medieval Wargames Buildings
Terragenesis offers a great photo tutorial for making medieval wargames buildings.