Thursday, May 24, 2007

Re: Plywood over light gage shear wall

Note that the 2004 AISI Lateral Design standard (adopted by reference by the 2006 IBC) Section C2.2.2(4) requires wood structural panels to be attached to steel framing with a #8 flat-head self-drilling tapping screw with a minimum head diameter of 0.285" or #10 with a minimum head diameter of 0.333".


---- Robert Kazanjy <rkazanjy@gmail.com> wrote:
> 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
> > > > > >
> > > > >
> > > > >
> > > >
> > >
> >


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