Rafter, Ceiling Joist Connection Question

[MountainDon]

I hope Don_P sees this in particular, but anyone can chime in.

For the drawing shown what would be the most secure method of fastening the rafter to the ceiling joist. Snow snow would be at least 50 psf, with a wise builder allowing for maybe 70 psf.



Collar ties not shown, but they might be used; maybe steel straps over the top. Material sizes to be determined and not important at this stage. 5/12 pitch because I don't like working on anything steeper.

[PEG688]

 Put the rafter on top and gusset each side with 1/2 CDX with the standard   two: <one> :  two staggered nail pattern.  Double up the pattern , big gusset say back to the crotch plus 12" .

[Don_P]

PEG beat me to it. Nail count, in this case for each member, would be close in the heeljoint table. (actually using the sloped rafter calc and the awc connections calc with plywood and your nail size would be better) (( I can review and see if I can get this closer using some info PEte sent if we want to go deeper, it'd probably take some of his help)) I'd include a vertical kicker from over the wall up to the rafter in the plated area. The CJ is a cantilever problem otherwise.

In old construction this was often built with a "raising plate", a board laid flatways on top of the overhanging joist flush to the outer edge and the rafters nailed to that plate. Jack Sobon's "Build a classic timber framed house" shows this method.

The one downside to this is if the fascia ever rots and gets to the framing this is structural to the entire roof rather than just the overhang.

[MountainDon]

I was thinking along the lines of gussets on each side. If the gussets were made large enough to cover back to the over the wall position, sections of 2x, grain vertical, and cut to be a tight fit between the joist and rafter above the wall could be sandwiched between the gussets.

If the AWC Connection Calculator indicates 20 nails, for example, that would be split between the two gussets (one gusset per side). There would be 10 nails per side and that would mean ten nails each for the rafter and ten nails for the joist, if I look at that correctly.