I was thinking the other day how would people build roofs after a doomeday with out metal being manufactured how would we do it I could come up with nothing so I ask for your thoughts.
If you have access to palm or coconut trees, a thick layer can be made into a roof. Secure them with the fiber of the frond stems. That's how it is done in our provinces. These can last 5 years with patching from time to time
Wood planks covered with slakes, or you can salvage metal. Hell if you were determined enough, you could cut open all the tin cans you found, flatten them out and nail them down like shingles.
Same way they did it in the not too distant past: wood, slate, thatch. Can idea is interesting though...You'd have to have a lot of cans but that would be interesting looking and I bet it would work.