I read in FHA (old) publication of timber framing/pole construction that 2X8 rafters (30" OC)and 2X4 horizontal purlins (35" OC) will adequately span between 14 to 15" in moderate snow load country. Any info out there on light construction spans like this - code acceptance, realistic replacement for 2X12"s ? Also, wwaht size must girder headers be to carry this load across 12' pole span ?
