I have used a sheet of Evergreen corrugated siding and Aluminum furnace tape. Cut a piece of 2 inch wide tape 3 or 4 inches long. Place face down on the Evergreen siding. Burnish the tape onto the siding cut to size with an X-acto knife. Peel the backing and stick to your building. It stuck very well to my primed basswood mine building.
I used HO scale corrugated foil for the roof on the side building of a N scale Model Power building. It doesn't seem to look out of scale and is a lot easier to find. Joe
