Hi Everyone, I am rehabbing a very small home in Southern NJ that was built in 1885. I guess for lack of a better description, the house is a "Cape" style in which the upstairs (2 bedrooms) follow most of the roofline/attic area. The plaster does level off at about 7' in the middle of the house so there is about 3' of additional roof pitch that is above the plaster/unfinished. I'm hoping that makes sense so far :) I am going to be installing a metal roof on the house. Currently there is no insulation or vapor barriers. There currently is an asphalt roof on top of a cedar shake roof installed on top of purlins that are in good shape. The inspector said (I do have proper permits pulled) since the metal is so light I can put the metal on top of the old roof if I install new purlins on top of the asphalt shingles. Or I can also tear off the old roof. I'm leaning towards tearing off the old roof because then I can just put the metal on top of the existing purlins AND I can insulate the space. I don't really have access to insulate most of the roof unless I tear off the old roof. My major concern is condensation between the metal roof and the conditioned space. I really only have room for 4" of insulation since most of the plaster is against the 2x4 (actual size) rafters. Towards the peak I could add a bit more insulation but that's only 1/3 of the interior surface area. Should I leave the old roof in place just to add the extra layer of "vapor barrier?" Should I tear the old roof off and put a plastic vapor barrier down (against the back of the plaster) and insulation on top? Or should I just use paper-faced insulation for 2x4 walls? I definitely cannot make the vapor barrier seamless since the plaster and purlins are already there. I would essentially be doing the best possible with trying to tuck it into existing cavities. Any advice would be appreciated!

Hi DIY forumgoers, We just bought a new detached home in Ontario, Canada. 5-year old house, faces south, nice neighbourhood. But our province's energy prices are among some of the highest in the country. So, we'd like to install some solar panels onto our roof (and eventually hook it up to a [URL="http://www.teslamotors.com/en_CA/powerwall"]Tesla Powerwall[/URL]). But my question is- does the presence of solar panels on a roof cause roof maintenance issues? After all, shingles need to be replaced every 10-12 years, and other roofing issues might crop up. I just don't want to find myself in a situation where the roofers charge us a premium for working around solar panel installations, which would negate any cost savings made from having the panels.