ModelRailroadForums.com is a free Model Railroad Discussion Forum and photo gallery. We cover all scales and sizes of model railroads. Online since 2002, it's one of the oldest and largest model railroad forums on the web. Whether you're a master model railroader or just getting started, you'll find something of interest here.
All kinds Main street building, houses, interlocking towers, depots, roundhouse, anything that needs a roof basically. I have a lot of "finished" buildings that just need roofs.
I've done a couple of roofs now with 600 grit sandpaper. If you cut it into 36" wide by 12' long strips it looks like roll roofing. You can paint it, one I did in a red wash and one in grey.
I glue mine down with double-stick tape, but glue or 3M 77 spray adhesive would also work.