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Re: Detail Review

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Bill,
 
Its an interesting detail.  Several things to think about.
 
1.  How do you connect the cross walls together (walls parallel to the joist) since the PSL is above the double top plate....will you have to add a piece of PSL to double top plate where the walls are parallel to the joist.  If you change the stud height of the cross walls to eliminate the PSL, then how do you connect the walls together.  I am sure it can be done, but its different from the normal standard framing conditions at wall corners.
 
2.  Your hanging the joist from the PSL which over hangs the Double top plate, so technically the PSL is in cross grain bending.  Yes you provide drywall under the PSL, and a block in the drywall to prevent rotation of the joist in the hanger, but do you want to count on it structurally. 
2a. Will Simpson give you full value for the top flange hanger.  Simpson reduces the the capacities of top flange hangers when they are placed over plywood sheathing since part of the seat bearing is on the edge of the plywood (which may be more of a problem than the PSL as shown in your detail). 
2b. Do you have to place the drywall on the wall prior to placing the joist...this may be an issue for taping and finishing of the dry wall.  If you wait till later to install the drywall, you definitely have cross grain bending in the PSL.   Do you need to add a block over the two layers of drywall for attachment of the ceiling drywall edge to the wall sheathing.
2c. Without the drywall on the underside of the floor joist, doesn't the PSL need to be covered by 2 layers of drywall to maintain the fire protection for the 2 hour wall.
 
3. Since you are hanging the joist from the face of the wall, why not use thru bolts for the shear transfer.  How do you place the nail in the upper top plate of the double top plate to the underside of the PSL. You have to nail the lower plate of the double top plate to the stud first, so is an additional nail needed from the lower top plate to the upper top plate.  How will the city inspector verify the placement of this nail/lag since it is concealed.
 
4. Is the detail cost competative with setting the joist on the stud wall.  In this detail, you have to pay for taller studs, say 6" taller, to eliminate the blocking between studs when joist sit on the wall. You also have the cost of the hanger which you wouldn't have when the joist sits on the wall.
 
Mike Cochran
 
In a message dated 8/5/2004 2:39:07 PM Pacific Standard Time, T.W.Allen(--nospam--at)cox.net writes:

Dear Colleagues;

 

My client has asked me to review a proposed detail. I have my opinions, but, being one with an open mind, I would like to get opinions from others.

 

The detail is here: http://www.AllenDesigns.com/projects/20401/20401_sk03.jpg

 

Your comments would be appreciated.

 

T. William (Bill) Allen, S.E. (CA #2607)

ALLEN DESIGNS

Consulting Structural Engineers

http://www.AllenDesigns.com

V (949) 248-8588

F (949) 209-2509