A customer wants a raised patio about a foot off the ground. He has asbestos shingles which I am not going to remove. Can I just put tar paper against the house, plastic, what? There is a gutter and an eve overhanging where the patio will meet the house so I don't think rain from above will be a problem, more so from the ground up. Usually I would remove the siding but this one is a little different. Suggestions?