I bought all my parts for an essentially flat-roof chimney installation today for my Heartland cookstove - all Selkirk products - ceiling support box, roof flashing, etc, etc.
First, insulation shield question: My ceiling is (from bottom up) plywood, 1/2" EPS (foam board), plywood, R-19 fiberglass, plywood, framing, OSB, rubber roof. OK, don't ask, I didn't build it, I just have to deal with it. It will be coming out in a few years when I save up enough cash to put a 10/12 pitch gable roof over it. Anyhow, as it stands, all insulation is blocked off from the chimney by framing, with >2" clearance on all sides. The opening was originally made for a 8" chimney. In other words, the EPS and fiberglass is "encapsulated" away from the chimney; the equivalent of putting the chimney through a piece of 6" thick plywood. NOW, the question is this: is an insulation shield required in this installation? I do not have enough room to put a Metalbestos brand insualtion shield in there (too tall and too wide at the base), so I would have to fabricate my own out of sheet metal. Also, the only thing that can get to the chimney are insects (wasps, ladybugs, etc.). I had a thought of buying a second storm collar to place against the top side of the celing support.
Second: My roof is roughtly 3/12 pitch. In the metalbestos specifications, I noted that for flat roof installations, a piece of sheet metal is required to be wrapped around the edges of the roof opening. What is the purpose of this, and does my 3/12 roof fall into this category? These are the only issues that are not "straight forward".
Any advice from anyone?
First, insulation shield question: My ceiling is (from bottom up) plywood, 1/2" EPS (foam board), plywood, R-19 fiberglass, plywood, framing, OSB, rubber roof. OK, don't ask, I didn't build it, I just have to deal with it. It will be coming out in a few years when I save up enough cash to put a 10/12 pitch gable roof over it. Anyhow, as it stands, all insulation is blocked off from the chimney by framing, with >2" clearance on all sides. The opening was originally made for a 8" chimney. In other words, the EPS and fiberglass is "encapsulated" away from the chimney; the equivalent of putting the chimney through a piece of 6" thick plywood. NOW, the question is this: is an insulation shield required in this installation? I do not have enough room to put a Metalbestos brand insualtion shield in there (too tall and too wide at the base), so I would have to fabricate my own out of sheet metal. Also, the only thing that can get to the chimney are insects (wasps, ladybugs, etc.). I had a thought of buying a second storm collar to place against the top side of the celing support.
Second: My roof is roughtly 3/12 pitch. In the metalbestos specifications, I noted that for flat roof installations, a piece of sheet metal is required to be wrapped around the edges of the roof opening. What is the purpose of this, and does my 3/12 roof fall into this category? These are the only issues that are not "straight forward".
Any advice from anyone?
