On Thu, 12 Nov 2009 06:45:39 -0800 (PST), Big_Jake
wrote:

On Nov 11, 8:54*pm, George wrote:
On the current series of This Old House, they're (among other things)
putting a two-story, one-room-wide-ish addition on a house. *The
addition has a gambrel roof, at right angles to the main roof.

For the ridge on the addition, they're using a double 2x12. *This seems
kind of massive, to me. *For instance, our (old) barn (not large, but
way bigger than their addition), also has a gambrel roof, and just *a
1-x-whatever for the ridge board.

I'd be interested in any thoughts on this.

Thanks,
George

I would guess that your barn didn't have a cathedral ceiling, and that
their addition did. Their ridge is a structural ridge, holding up the
roof, and needs to be pretty big, especially if a snow load is
involved. A double 2x12 is on the small side. We have a 20' long
addition on the back of our house that has a double 14" Microlam as
the ridge.

JK

OK, thanks. Just to clarify: with collar ties (and suitably-sized
rafters), the ridge load would be much lower? When you say the ridge is
holding up the roof, does that mean their rafters are in tension?

Thanks again,
George