Thanks for the good pictures! My key to understanding the reframing is this sentence: "The new rafters don't reach to the ridge, not really a ridge, just a 1x6, and are supported by 2 sistered vertical 2x4's off the load bearing wall."

In other words, where the old framing was transfering the roof loads out only two supports (the two side walls), now the roof loads are carried by three vertical supports (the center load bearing wall and the two side walls). The horizontal joists on the other side of the house don't carry much (if any) load now but they do serve the important function of stabilizing the whole structure by the triangle form by the rafter/joist/sistered 2x4's combo, as does the additional ceiling/roof framing in the new section.

Looks like a nicely done job. Congrats!

I'm not a structural engineer. And if you have a drawing of all this with someone's PE seal on it, I'd be hesitant to contradict that. Plus, if it's all built, the horse has already kinda left the barn, right?

That said, and with all kinds of other disclaimers and weasel words, I'll tell you what I think. It looks to me like all of your new ceiling (right side of the room in the first photo) will be actually hung off the old/new rafters.

I say that because I don't see any support for the beam ends in that first picture. I'd think you'd want to double-up, maybe triple, the stud on the end wall where that's landing. And I can't tell whether that beam supporting the short joists has a stiffener on the bottom (tough to see in the first photo), but if it's only 2x10 or so it looks kinda marginal for what I'm guessing is a 12'+ span.

Please take this with a big grain of salt. Probably the best thing to do is get your engineer to make a site visit and re-confirm what he designed.

Thanks for the comments.

As a point of discussion, I'll post these basic drawings which I'm sure many have seen:


It was always my understanding, that on a house with gable ends and no ridge beam, with roof rafters that just lean against a 1x6 at the ridge, as in this house, there's an outward horozontal force component which tends to push the side walls out at the top. The rafter ties, under tension, work against this outward horozontal force as do the ceiling joists. Now that the joists on one side of the house are gone, only the widly spaced, 1x6 roof rafters are left to counteract the outward horozonal force.

formula1 - I think I see what you're saying: that the triangle formed by the new vertically oriented, sistered 2x4's and the old ceiling joists and old rafters on the side of the house where no work is being done, (where the ceiling is still a flat 8 footer), is providing stability for the whole roof. I'll have to think about that and maybe I'll provide a better photo of the ridge area.
Like this?:

Thull- I think what you're seeing as a beam isn't a beam - it's just a 2x6 nailed onto the ends of the remaining 2 foot sections of the original ceiling joists. This 2x6 is only there to tie the old joist ends together, what blocking would do, and to provide backing for drywall; it has no support funtion.

A friend had their ceiling peaked on one side of such a house and the contractor used 2x10s or 2x12s for rafters with beefy connections to the wall studs to achieve the strength that the removed ceiling joists had provided. Now the ceiling and the walls connection is about 7 feet high, so they lost a bit of headroom at the sides of the room.

Hi,
You now have a queen post truss. It's going to work. Add a few more nails to the 2x4 rake ceiling joists.
The detail that bothers me is the lack of a proper bird's mouth and joist hanger on the new larger rafters. This stupid cut has reduced their strength to less than a 2x4. A split is bound to start at each rafter where it bears on the plate; maybe this can be remedied with some steel strapping. I'm fairly confident that the engineer would be aghast.
Casey

Metal hangers were added to the new rafters after the photo was taken and the engineer did tell the contractor to cut them as shown. I thought that was scary too so I got a closeup. Guess he figures, as I think is the case with all stick building, that since there's so much lumber used, you can pretty much hack away at will and there's still enough left to hold the house up. This is all going on at a friend's place and I might do the same to a small bathroom in my house, so I got interested.

I read about the queen post truss but I only found info in the context of timber framing where there's a ridge beam. In this case are those 2x4 rake rafters in tension or compression? Are they aiding the rafters in holding the roof up or are they preventing the top of the side wall from bowing outwards. Those book drawings I posted of the sides falling outwards are what I'm thinking of when wondering if the rake 2x4 rafters are in tension.

Sorry I'm not getting this into my thick skull.

Thanks,

Bill

OK, I think I get it now. You're last sketch is pretty much there, except you have a couple-foot cantilever of the old ceiling joists off the center wall. That's supporting the new, short ceiling joists on the righthand side of the first photo.

I guess you'd want to make sure those stub joists are secured well enough that they won't rotate any.