Originally Posted by
Terry Beck
So are you saying that in a gable style house with a cathedral ceiling and a structual ridge beam, that roof load is now carried by whatever supports that ridge beam (the gable wall)? Or does the majority of the roof load still travel down the rafters to the side walls? I guess my question is, do the gable walls in a house with a cathedral ceiling and structural ridge beam(s) now become the main support walls?
Terry,
With a structural ridge (I would drop using the term "cathedral ceiling" as that has various meanings and could lead to confusion) the roof load is carried by BOTH the support for the structural ridge AND the bearing walls. The roof load is carried by the rafters and transferred to the structural ridge and walls on which the rafters are bearing. The structural ridge may be supported by the gable end walls or it could be supported by columns.
Think of it this way: You construct a post and beam 'shed'. You set 4 posts, then set 4 beams (2 sides and 2 ends), then install a center vertical column at the center at each end, then set a structural ridge (beam) on those two vertical supports - now lay rafters at each end from the ridge to the corner posts to keep that vertical column vertical.
Now lay the rafters on the structural ridge (beam) and on the side beams (between the corner posts).
No walls, nothing bows out, the roof load is carried to the 4 corner posts via the beams on the side.
No, install walls below the side beams. Same thing, no difference.
Now, let's change it a little, instead of side beams, construct two bearing wall setting on footings. Same thing, no difference (other than if the walls are long you will need to keep them from bowing in or out).