Roof: Gabled end overhang
I am developing a project where I want a 14″ (+-2″) unsupported roof overhang. I was thinking about using 2×4 outriggers approximately 16″OC on the flat fastened to the first 2×8 inside rafter, notched into the end rafter that lies directly above the end wall, and then having it run out to the fascia rafter.
I want the outrigger to lie on the flat so as to minimize any obstruction of airflow through the rafter bays as much as possible, yet I want them to have direct contact with the roof deck for connection purposes, and, although I feel this maybe unusual, I even thought of laying some adhesive on top of the outriggers before the 5/8″ roof deck goes down to make the overhang even stiffer.
 
Anyone have any experience with this type of overhang?
Thanks
Replies
Standard detail here is a gable end truss that's got its top chords dropped by 3.5". Horizontal members are laid across this, starting from the first inboard truss, to support the gable overhang. The truss manufacturers even deliver the horizontal members assembled into a sort of "ladder", so they're ready to be laid across the the end truss. Reasonable airflow is provided via the horizontal "bays" thus created.
Yes. You will see that detail in framing books.
For example, see: http://www.tpub.com/content/construction/14044/css/14044_70.htm
As Dan points out, since trusses are more common, the method in the upper picture is more common.
I'm not sure about your concern for air flow. Are you referring to flow from the wall to the ridge within each rafter bay? Is this a cathedral ceiling?
Joist hangers on lookouts
The last one I did the Structural Engineer required inverted joist hangers at the inboard ends of the lookouts.
I've never seen that before, and of course we put them on right side up and had to take them off and replace them upside down. Makes perfect sense once you think about it for a minute.
I've done it many times. Works fine. No need for glue.
If ya lay the oulookers out 4' O.C. from the face of the subfascia, the plywood will break on the outlookers.
I've only seen one person break their plywood over the gable. And they weren't particularly smart, so I wasn't surprised.
My builder did it, but then, as you say, he wasn't particularly smart.