Currently, the outer walls of an old cottage are constructed as follows. Beadboard, some form of paper, sawdust, some form of tar paper, and then vertical board-and-batten siding. The plan is to replace the sawdust with hunton wood fiber insulation when the siding is later replaced, and then also have a wind barrier and an air gap behind the siding. On the inside, we plan to install new beadboard over the old beadboard. The question is whether a vapor barrier is needed, or if the old beadboard and the old paper can function as something similar?
