Re: Plywood over light gage shear wall

Jim-

Take a look at my latest reply to Tom..........

I was thinking about the washer heads used for frame assembly.


Tom's scaling of the photos is probably pretty close.   I think there might be a mistake in tour info in that report footnote that I talked about.  :(

I had heard the same thing about the pneumatic pins.....we even experienced flange bending with screws but when the screws finally "bite" they draw the flange back to the sheathing.

Our studs were 20 gage which I think is on the light side....there would be less of a problem with thicker studs

cheers
Bob

On 5/23/07, Jim Bessley <jbessley@gmail.com> wrote:

Bob,
Yes, I understand and I do appreciate your input.  On another note, some time back I read about pneumatic pins for shear walls and I heard from someone on this list that they had a problem with the pins bending the flanges of the metal studs without getting good penetration.
thanks again,

Jim

On 5/23/07, Robert Kazanjy < rkazanjy@gmail.com> wrote:

Jim-

I realized you were quoting the code requirement but just wanted to give you my limited experience with plywood over steel studs.

One problem we had when sheathing the walls..... was that the threads would grab in the plywood (or OSB) & then the plywood would lift off the studs.  It was a real pain.....looks like Tek now makes a screw for wood to steel studs that has a reaming wings that avoid the problem.

I think its call Ply-Tek  or something like that

I would suggest using as large a head as readily available (esp for OSB which is not very strong at the screw hole level)  plus the construction crew will like a screw that doesn't lift off.........you'll get better workmanship as well.

cheers
Bob

On 5/23/07, Jim Bessley < jbessley@gmail.com> wrote:

Bob,
Thanks.  I was just reiterating the requirements from the code.  Last night I was able to locate some dimensions on the internet.  It appears that it is a #8 flat head screw.  that is the minimum head diameter allowed.  it appears that a #8 flat head can have up to a .332" diameter.  close to the 3/8" you are talking about.
Jim

On 5/23/07, Robert Kazanjy < rkazanjy@gmail.com> wrote:

Jim-

That's a pretty small head diameter for a self driller / tapper for use in plywood

A number of years ago we did plywood shear wall (CoLA Shear Test Program) over steel studs & I recall that the screw heads were more like 3/8" or even larger.  

I don't have the data readily available due to a crash   .........  archived  somewhere

Maybe the specs have been changed but it seems to me that a bigger head (3/8 or 7/16) would be better than .292" .  A head dia of .292 seems  pretty skimpy.

The screws were #8's or 10's


cheers
 Bob

On 5/22/07, Jim Bessley < jbessley@gmail.com > wrote:

I am trying to design a shearwall using the 2003 IBC for plywood sheathing over light gage metal studs.  the code says that the screws should be self drilling and tapping screws with a .292" head diameter.  I can't find the screw size that correlates to this head diameter.  Can anybody out there help me.

thanks,
Jim Bessley