The roof covers a lot of surface area so special attention needed to be given to getting the coloring right. The base material was Evergreen car siding.
In terms of coloring the order of application was:
-First, the entire surface was painted with Rustoleum light gray primer and allowed to dry overnight
-The next day the entire surface was given a wash of burnt umber artist oils and mineral spirits using vertical strokes. An effort was made to work in vertical streaks. Again, I let this dry overnight.
-I wanted subtle horizontal bands to imply edges to the corrugated metal sheeting so I applied masking tape on the surface and lightly dusted the tape edge with an India Ink/alcohol mix in my airbrush (2 tsp ink/pint). I was in need of corrugated roof sheets and luckily, I was able to find some from a roofing repair someone used a few years ago. The whole project would have been ruined if I didn’t have these sheets since I needed a specific shape and size sheet. Once I had three noticeable horizontal bands I went over the entire surface again with a dusting of the ink/alcohol mix.
-I masked off a few random panels and painted them either dark gray or light gray primer.
-Finally, I used a mix of brown and rust chalk to add streaks to the lighter panels.
The back side of the roof peak won’t be visible so as I worked I always started the paint steps there to make sure a technique would work before moving to the more visible front side.