Framing Roof on Cantilevered Ceiling Joist

[radean]

I am a builder and was wondering if any one had experience with frame roofs where the rafters set on top of cantilevered ceiling joist? We did one job that way and had to do a lot of xtra blocking to satisfy inspector with load transfers. I was wondering if the is any code on this or it has to be done with trusses?

[Don_P]

Never done it stick framed I've only done it with trusses. He just required a row of blocking over the exterior wall? I think I could dig up that much in the codebook.

Old time construction extended the CJ's over the wall then a 1x or 2x "raising plate" was nailed flat across the tops of the joists flush with the outer edge then rafters with only a level cut were nailed on top of that. I've found that in the period between the timber framed step lapped rafter seat and the modern birdsmouth.

[Studio43]

It can be done. The ceiling joist should to be sized properly to carry the load as a cantilever condition. And they will need to extend back into the structure far enough to resist rotation. A bearing plate would lay perpendicular to the CJ for the rafters to rest on. As a side note, I recently was doing a story and a half style framing and the required nailing at this condition was unable to be met. We were required to add a metal strap at each rafter to tie back the rafters to the CJ to enable enough nailing to resist horizontal thrust as well as uplift.