While inventorying what needs to be done in my new attic (per Tom Silva's remarks on a TOH episode) before adding insulation, I noticed that the sewer gas vent pipe arising from the bathroom does not proceed through the roof, but ends about a foot above the attic floor. The pipe which runs through the roof drops down and sits almost but not quite square on top, about an inch or inch and a half offset. There is a metal clamp sitting at the top of the lower pipe, clamped to it alone, as though someone tried to make the clamp bridge these two pipes and failed. My plumbing skills stop at replacing washers. Clearly the pipes need to be connected, How do I do this or must I contact a Real Plumber? Thank you for your insights! best, M.