Removing interior gable-end wall

[SocklessJ]

My experience is in steel structures, but this question has to do with my house.

My living room has a cathedral ceiling, which intersects the main house at the gable end (see attached sketches). I’d like to open the wall between the living room and dining room. While my knowledge of light frame construction is limited, here’s what I’m thinking:

Vertical loads. The floor joists in the dining room run parallel to the gable end, so it’s basically a partition wall. But I’d still like to tuck an LVL behind the band joist.

Lateral Loads. This wall is probably functioning as an interior shear wall because nothing else provides shear resistance in this plane due to the windows. So instead of removing the entire wall (or adding two columns), I could leave 24” wide walls on either end. These could be sheathed with plywood and connected to the band joist & new LVL above to form a portal frame. This would be similar to the APA garage door portal frame details I came across.

Any thoughts?

 

[Jerehmy]

If you have a cathedral ceiling, im 90% sure you have a ridge beam (as opposed to a ridge board). The other 10% would be a beam at the top of the north and south living room walls to eat up the thrust from the rafters which is unlikely but possible. Thus, the wall you want to open supports the east end of the ridge beam and should have a decent amount of axial load coming down.

From your sketch, that wall is also the shear wall for the larger portion of the house. Looks like there are numerous openings in that wall. The section you're trying to put a wall into looks to be the longest and therefore stiffest shear wall. You're going to lose a lot of stiffness in that wall when you open it up. I'm not even sure you have enough shearwall/braced wall line to meet strength requirements based on your sketch.

I'd check and make sure I have enough remaining strength in that shear wall/braced wall line with the opening. Then I'd see how much more deflection I'm going to get with or without a portal frame.

 

[SocklessJ]

Thanks, Jerehmy.

I had the same thought about the ridge beam, and cut a hole in the drywall to see if there was a double stud to support the ridge. But I don't see one. However, in my crawlspace there is a pier at the center of the wall. The two walls running N-S in my living room appear to be bowing out due to rafter thrust, so maybe therr is no ridge beam and the design was flawed from the beginning (1970s).

 

[XR250]

1970's? - probably no ridge