I'm trying to design a kingpost truss to span approximately 30 feet. I'm thinking of more or less duplicating the truss from the Lynnsfield Meetinghouse detailed in issue 72 of Timberframing.

My question is this: Since the kingpost is already in tension, what are the potential risks of replacing the 30 foot bottom chord (tie) with two 15 footers splined into the extended (pendant) kingpost rather than wedge-dovetailing the latter into the tie? Should I reduce the dimensions of the ties to reduce weight while somehow still maintaining tension against rafter spread? Should I beef up the upper chords (inner rafters) to help suspend a heavier kingpost (to resist end shear) without buckling?

I'm trying to avoid the difficulty of obtaining and handling such a long tie. Any advice, including suggested dimensions for timbers, would be greatly appreciated.

Matt Champagne
Hammer & Chisel, Inc.