So I finally found a used Avalon at the right price and now want to install in my two-story cape. Want to install the chimney through the center of the house to avoid about 15' feet of pipe sticking out of one of the corners. The chimney will thus have to run through a second story bedroom before going through an attic and out the roof. What type of pipe do I have to use for the section in the bedroom. Double layer stove pipe or chimney pipe? And after it's installed can I box it in? Thanks in advance.