Bearing trusses on GYP Board 3

[beemer218]

Architect i am working with has to have a continuous rated partition and I have wood trusses that need to bear partway up the wall. He is suggesting using 2x6 studs then switching to 2x4 studs creating a shelf for the trusses. But, he wants to wrap the gyp board over the plate so my trusses will bear on gyp board over a 2x plate. Will this work?

 

[MiketheEngineer]

If the trusses are about 10' long!! Over time you will crush it

 

[charliealphabravo]

If there is no blanket code prohibition then i suppose you could design the bearing area of the truss to stay below the compressive strength of the gypsum. Off the top of my head I don't know how practical that would turn out but I think it would be better than using a face mounted hangar which would then have a 1/2" or more fastener standoff depending on how many sheets of gypsum you have.

You will need the gypsum association design binder. i think it is available entirely on PDF now.

 

[JAE]

I wouldn't do it.

 

[msquared48]

Typical example of an Architectural solution that would make matters worse. Trust your guts here. You wouldn't have asked the question if you didn't have doubts.

Although they will never admit it, Architects hire us to keep them out of trouble. They just need to listen.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[tony1851]

This is a typical instance of the tail wagging the dog.

 

[beemer218]

tony I agree. I need to bark louder and get some "bite"!

 

[tony1851]

Yes; if you have a gut feeling that it isn't right, then it probably isn't.
Instead of agonising over it, you need to tell the architect that it can't be done that way.
It's his problem, not yours. Why spend time trying to solve it for him?

 

[beemer218]

Amen.

 

[KootK]

I've faced a similar situation. We bolted a ledger to the side of the stud wall, outside of the continuous gypsum sheathing (gypsum sheathing running between ledger and wall studs). We then hung the relatively short span trusses from the ledger using face mount hangers.

To do this, we used larger diameter lag screws designed to resist the bending stresses resulting from the effective gap between the wall studs and the ledger. If I remember correctly, we also replaced the 2x studs with 3x or 4x members better suited to receive the lag bolts.

Don't get me wrong, this detail made my stomach turn as well. It worked by the numbers, however, and was the best option that we could come up with. The condition that I faced only extended a short distance where a stair shaft abutted a corridor wall. If your condition runs for a long stretch, my detail may be prohibitively costly.