My model is a combination of kitbash and scratch build. It consists of 3 buildings - the large building uses the walls and windows from a cheap plastic kit (I do not recall what kit as I saved those portions and discarded the rest long ago). The center connecting section is scratch built from wood. The third section with the deteriorating stucco is based on 3 walls of what I think was a military model of which I only had the three walls and roof.
The rear of the complex is somewhat plain as it will face away from the edge of the layout (when I figure out where I can put it). This thing just grew from a germ of an idea - or two, and the kit pieces in my scrap box.
This was an interesting project, including my research on what Gutta Percha was. If you want more info on that just do an Internet search. The structure itself could be anything. I may add more details when I install it on the layout.