Help with a residential framing issue 4

[Bhotar3]

Contractor friend was hired to finish the construction of partially completed home, after the original Contractor walked off the job. Following a permit inspection, one of the workers had some concerns about some shifting-out of the top of an art studio exterior wall following a wind event.

The room is gable framing, and the ridge beam is two 2x10" LVL beams. The ridge beam span is 25'. The pictures attached show the room shortly after framing, and in its existing condition.

I believe, after it was framed, they cut the ridge beam supports and added this 6"x10" cypress beam and these "decorative" 6x6 cypress rafters that are simply bolted into the wall top plate and into the ridge beam.

My belief is that the original ridge beam (two 2x10s) is undersized, and the room isn't adequately braced laterally. After running the numbers, I think the ridge beam should have been 3-ply 2x16. They were wondering if they could post-install the new ridge beam under the 2x10 ridge beam and then "wrap" it with cypress to make it appear like a beam. My issue with that is I'm not sure how the rafters will tie into the new ridge beam or how it would be braced laterally.

My initial 3 options were:
1. Remove 2x10's, replace with 2x16's (Most intrusive solutions because it would take a significant rebuild)
2. Add collar ties for lateral support.
3. Exposed Cables from wall top plate to wall top plate.

Anybody have thoughts here?

 

[phamENG]

The easiest solution might be losing 16" of floor space and just frame a new 2x8 wall with the appropriate full height studs inside and tie them together. They'll have a really thick wall, but the alternative is probably to shore up the roof, remove the end walls, and reframe them with 2x8s or even 2x10s anyway.

 

[Bhotar3]

My question is still on the ridge beam sizing.
Appears to be a 6”x10” solid cypress beam.
Doesn’t seem to be large enough to accommodate half the roof load for cathedral framing

 

[phamENG]

You'd have to run the numbers on it. Is the design stress greater than the allowable? Is the calculated deflection higher than allowable?

 

[Bhotar3]

On the end wall with the two large windows,
Are we still having to address the hinge
Condition here?

What section of the code references vaulted ceilings like this or discussed the continuous framing requirement?

 

[Eng16080]

On the end wall with the two large windows,
Are we still having to address the hinge
Condition here?

I don't understand this question. You have to design the wall to resist the required loads. And there needs to be a reliable load path all the way to the foundation. Personally, I wouldn't worry about finding a section in the code that tells you to do this. This is just the basic methodology for structural design.

For a wall like this, for some reason it's easier for me if I imagine it as a floor. I imagine then putting a load on the floor, perhaps 20 psf (which is usually a conservative wind load where I'm located), which happens to be about half the normal residential live load. Just looking at the framing here, I wouldn't feel too great if this was a floor in my house and I was gonna invite a bunch of people over to stand on it. It looks like the double 2x6 plate above the large windows will be the weak link. I wouldn't be surprised if other framing fails as well.

 

[jerseyshore]

Gable end walls after the ceiling is vaulted are always overlooked and most likely to show issues quickly after sheetrock is installed. It's windy all day every day so maybe you're not in a snow area where the ridge will show issues right away, but that sheetrock will crack during the first storm.

I never mess around with gable end walls personally. Usually recommend adding new full height studs. Maybe doubles here since it's pretty tall. I like pham's suggestion (always do ) of just framing a new wall in front. That's pretty easy.

I have no problem adding a new ridge beam under the existing. If it's a deeper LVL beam I usually add little "collar ties" that are interrupted to brace the bottom of the beam. So what if the ceiling is a little bit flat at the very top.

 

[Bhotar3]

Just spit balling here. Can you not reinforce the hinge joint with plywood on both sides of the end wall?

 

[jerseyshore]

That would help somewhat, but usually if someone is doing an interior reno they aren't re-siding the entire house too so you would only be able to add plywood to inside. On paper a double top plate vs a double top plate + plywood overlap feels like a negligible difference.

 

[lexpatrie]

Bhotar3 -

Not based on any recognized published engineering literature that I'm aware of. Plywood was used back in the day as gussets for wood trusses before metal plates, but the "design standards" are from the 1950s and were never code anyway, they were primarily used on non-code (agricultural) buildings and/or codes were not that restrictive/specific. On a wall there are joints running across (perpendicular) to the studs, so where's the load transfer? We do transfer uplift loads on the exterior through the plywood into studs (for uplift), but...

There are plywood sandwich beams in the old UBC, but those are beams, not studs.

 

[TheDW]

ust spit balling here. Can you not reinforce the hinge joint with plywood on both sides of the end wall?

You would have to do a shear flow check based on how many nails you have between the sheathing and the studs, if you wanted to check the stress levels...and then you have to account for breaks in the plywood. For deflection it would help but good luck putting a number to it with any real confidence

 

[bones206]

Another option is to beef up the double 2x top plate and design it as a wind girt. It could be installed on the inboard side of the wall and wrapped in whatever finishes are desired.

That might take care of the end wall studs, but it seems there may be other framing issues to deal with as well.

 

[Bhotar3]

*UPDATE*

These end walls are framed out of 2x8s.

Does this change your opinions at all of the hinge condition, or should it still be addressed?

 

[bones206]

It should be evaluated. The double 2x8 top plate may work as a wind girt.

 

[lexpatrie]

If the double top plate works, then the end connection is the question..... particularly for the "negative pressure" on the exterior wall case. I suppose the gypsum could be considered to brace the compression side of the plate for that case, as well.