Curtain Wall Design

[CoachChad]

We just erected a metal red iron building. The metal building deflection is L/240. We plan to balloon wood frame two 18' tall exterior walls of the building and cover these walls with thin stone veneer. These walls are non-load bearing walls. The walls have lateral support beams at 10'H and 16'6"H. I am trying to determine what material to use for framing the wall. The architect had used #2 SYP 2"x6"x18' studs. I was concerned the #2 SYP may not achieve the minimum L/240 deflection needed for the stone veneer. We were considering LSL, but it doubles the costs of material.
LSL 1.35 1 1/4" x 7 1/4" x 18' can clear the entire 18' with a deflection of L/497 per LP data sheet.

I am concerned about cracking of the stone if we do not use appropriate materials.

What material have people used successfully?

I would also like to hear recommendations for attaching the wood framed wall to the lateral supports and top sill. I was considering Simpson Bypass Clips. These would maintain the lateral rigidity while allowing some vertical movement. Any advantage of a fixed clip?

Thank you for your help.

 

[JAE]

Use metal studs.
Design the studs for strength based on components and cladding wind.
Check studs for C&C wind at 70% of the calculated deflection per IBC.
Limit stud deflection (via stud depth and/or thickness) to that recommended by the stone veneer supplier - or L/360 (in my view). Larger deflections may be allowed.
Use slide clips for allowing vertical deflection of the main building frame members vs. vertically rigid studs.



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[NorthCivil]

I've been approached many different ways to do it, but in the end, I've never been able to sign off on adhered veneer (thin stone veneer)

I made a post here on Eng-tips looking for advice about it a year ago and was met with the deafening sound of crickets.

Not sure of your area, but adhered veneer is essentially the same as face applied stucco when it comes to weathering. So if you typically need a rainscreen in your area, it's a no-no.

 

[Ron]

Agree with JAE...if you have any windows in the wall, check lateral deflection as well considering the additional studs at the window will create a stiffness absorption condition. Also agree that deflection should be limited to L/360 since thin stone veneer is actually just the finish on a stucco system. Make sure that proper waterproofing and flashing integration are done at all penetrations.

 

[XR250]

The architect had used #2 SYP 2"x6"x18' studs. I was concerned the #2 SYP may not achieve the minimum L/240 deflection needed for the stone veneer. We were considering LSL, but it doubles the costs of material.
LSL 1.35 1 1/4" x 7 1/4" x 18' can clear the entire 18' with a deflection of L/497 per LP data sheet

If you are already looking at 7 1/4" LSL studs, Why not just use 2x8's? Most likely going to be alot cheaper than metal studs from a material and labor standpoint?

 

[jayrod12]

If you have a lateral support at 10ft, why not tie the wall in with vertical slip connections and then I'm sure 2x6 studs will meet the L/360 requirement.

 

[XR250]

May not even need slip connections if they are girts.

 

[dik]

Also, leave a deflection gap for the exterior wall and for veneer, brick, etc. (brittle). Deflection requirements for 'rubberised' EIFS systems OK. I usually limit deflection to L/600 or L/720, depending on my mood at the time (actually depending on the quality of finish and end use). Good reason for using steel stud... but, brings with it thermal issues.

Dik

 

[JLNJ]

Is this a Pre-Engineered Metal Building? Which direction is the l/240 deflection, downward or sway? If it's a typical metal building the sway will be far in excess of h/240.