shingles on a low-pitch roof
I'm buying a house, but having the seller replace parts of the roof. The porch is about 4'x12' with a pitch of about 2, maybe less (I haven't had a chance to measure). The owner has put a 30 year asphalt shingle on it, over the existing roll roofing (which was in poor condition). We are trying to insist that they put down a continuous membrane of some kind, but their roofer claims that shingles are better in this situation. This seems to fly in the face of reason and all the research I've done. Any thoughts?