Balloon Framed Wall Detail 2

[dhoward26]

Has anyone ever seen a detail like this before or done one? I am reviewing a design and don't know if this is a legitimate connection without seeing some sort of verification.

 

[dhoward26]

I haven't ever detailed a wall like this and haven't seen any of my mentors do it either so it makes me question the validity.

Thanks

 

[ToadJones]

why not use full height studs?

 

[dcarr82775]

Looks like a terrible idea, those straps will never be installed tight enough to work

 

[dhoward26]

I agree about installation.

It's located on a gable end wall with a scissor trussed roof. Unfortunately the architect put a stairway to the second floor at this location so it has to be balloon framed. It's 26ft to the bottom chord of the peak of the scissor truss. I'm recommending 1-1/2"x7-1/4" LSL studs for it. Timber strand has tables for walls like this.

 

[dhengr]

One way to prevent hinge action or movement is to remove the hinge. I agree with Toad and dcarr.

 

[ToadJones]

Good call on the LSL's.

Not only for structural reasons....you can't build a wall as the have shown and get it straight and flat. There will be a bulge/bow to the wall almost every time and it will make the finishes very difficult.

 

[Teguci]

You could lap them side to side and then add a sheathing detail for added moment. Another option would be to hang this from above and keep the system under axial tension. Metal studs might do the trick. I agree that this detail is susceptible to problems.

 

[dcarr82775]

LSL's are wonderful when architects make that sort of thing happen

 

[msquared48]

This is a knuckle joint regardless of the straps. If we could post 72 point type here, I would post one big "NO"!

Full height studs ONLY, regardless what they are!

Quite frankly, this looks like something an Architect might do rather than a structural engineer.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[shobroco]

Who called that a balloon frame? It's platform framing with no floor. Balloon framing has full-height studs, which is the only way to do it (whether by lapping multiple pieces to build up full lengths or by using LSL) UNLESS the wall is shorter in length than it is in height, when you may be able to span wall-to-wall horizontally with a multi-ply plate like you show that will take the wind load.

 

[4thorns]

Here is some info on the straps. Seem to be designed for tension only. May have some resistance against lateral forces but was probably primarily installed as a hold down.

http://www.strongtie.com/products/connectors/cs-cmst.asp

I agree with shobroco, not balloon framed but if the intermediate double plates can do the job then it might be good to go.

 

[dhoward26]

It's a 26ft long wall. I don know what else to call it besides ballon framed...or attempted balloon frame.

Regardless, I won't approve it in my remove and am sticking to the LSL's. I hadn't thought about putting additional 2x's along side the joint. But that seams like more work than it is worth and there is always the construction error aspect and nails loosening over time. I had a post a while back about design concerns in this are where I'm marketing at, and this is another example of those concerns. I talked with the contractor on the job about this detail because I know him personally and he said he has done a few like this. Pretty concerning.

 

[4thorns]

I've seen what it takes to drive a nail in that stuff so let's make it a little easier on the builder. Use an engineered post from floor to roof at the center of the gable if it's reasonable and frame in the rest with dimensional lumber. Intermediate double plates at the height of the side walls will then only span 13'. Bear in mind that the roof load is minimal since they are using trusses.

 

[dhoward26]

I like the full height column idea. I've done that in vaulted breakfast areas before. I will put that in my recommendations.

 

[BAretired]

The detail would probably work okay if the plates did not shrink. Unfortunately, they do and you can count on about 1/8" per plate or, in this case, 1/4".

The straps could work satisfactorily if they could take compression as well as tension, in effect making the studs continuous through the double wall plate.

BA

 

[ToadJones]

Well, with all due respect, a sore wrist and forearm is no reason not to use LSLs/LVL,s.
If I was the contractor and I would refuse to build the wall as it is shown.
Quite frankly, that detail is just plain rookie.

 

[Ron]

Hope you're not in a seismic or high wind area! You might find the second floor in the next county.

Full height studs only! That's one of the criteria for balloon framing. This looks like a bastardization of platform framing.

For the length (height) you'll need engineered wood (LVL/LSL). Tough to get a 26-foot stud, particularly a straight one.

 

[ToadJones]

We built a home once that had a 24' tall wall for a long stretch of the back wall of the house. There were no offsets in the wall to stiffen it. It was before LVL's were common and I believe 2x6 were called out for the walls (We were just the framing contractor).
We actually had 24' studs and they weren't too bad. But, the wall was so flimsy we had to go back and build flitch beams in place every so often. This really sucked because we had to account for wiring so the flitch plates had to be drilled ahead of time. The whole thing was a disaster.

 

[dhoward26]

Well, after a phone conference last night, I was asked to provide a solution to the issue. So, here is what I have come up with in Lieu of the full height LSL/LVL studs. I threw in other standard details for the transfer at the top of the Glulams to the roof diaphragm. Not a bad look though. I'm getting paid to do it, so might as well.

The straps at mid-height are to transfer the shear from wind going the other direction around the stairwell...it was left out and was a little more complicated than the guy thought.