housewright --

I can see 2 reasons to frame this way.

1- To allow the use of wind bracing when there is no purlin to brace to.

2- More importantly, the use of a ridge beam facilitates scribing the roof planes as 2 separate units and keeps you from having to scribe each rafter pair seperately -- it's a time saver in a scribed frame. There may even be a way to tumble all the commons -- that would really save time.

As for the 5 sided ridge it allows the tenons of the rafters to be more or less sqaure -- much easier to scribe than if the ridge had plumb sides.


Gabel