Expert: Richard Taylor, AIA - 5/12/2004

Question
I am in the process of finishing drawings for a 2-story lakefront home that has about 80% glass on the two floors/side facing the lake. The plan is for 2X6 stud wall construction with mid-span LLV beam and post for open floor plan and the specs for the front are 4 windows (approx 7X7') per floor with double french doors between each pair. The engineered lumber guy specified three 14" by 1.75" LLVs for header but suggested I need more bracing because this is a moment connection. Upright supports are four units of three 2X6 screwed together and four 2X6 at corners top and bottom floors with Simpson post to beam connectors and 12X12X2.5" T-plate  or elbow at all corner and perpendicular connections. I also have 2X12 tie plate bolted inside the upright supports where there will be shelving to hide it along bottom floor. With 3/8" sheathing on the whole structure and floors composed on 14" engineered I-Beams 16o.c. (house is 36X36') do you think I need a better bracing or moment connection? Do commercial projects get away with all glass by using embedded steel frame or something to that effect? Any input you can provide is much appreciated.
Tom

Answer
Tom:

Thanks for your question!

Wish I could help you here, but you really need someone to look at it on-site.  It sounds solid, but without running the numbers there's no way to be sure.  Your biggest concern isn't the vertical loading, it's the horizontal load from the wind.  You've got a lot of area and very little structure so the horizontal structure is critical.  In similar situations it's not unusual for us to use PSL columns or vertical LVL columns, or steel tube columns, or even 2 x 8 walls.

I suggest you find a local engineer or architect to run some calcs for you.  If it needs stiffening, you want to find that out now, not after a failure!

Hope this helps!

Richard Taylor, AIA
Richard Taylor Architects, LLC
www.rtaylorarchitects.com