GWB over Plywood

[WBUW]

Can someone tell me where to find values for application of gypsum over plywood? Know this is commonly done for fire protection, can't find the table or line in the IBC for the reduction.

Have a similar situation where I was hoping to use these values.

Thanks

 

[WBUW]

Whoops, should read plywood over GWB

 

[WBUW]

Nevermind, stupid question its right next to the conventional shearwall values. Duh..

 

[IceNine]

IBC table 2306.4.1 addresses this. The last column in the table gives shear values for panels applied over gypsum sheathing

 

[RARWOOD]

Why do you apply the plywood over the GWB?

 

[WBUW]

I actually have not had a reason to use that in my line of work.

My understanding is the gypsum board provides some fire protection, I want to say its something like a 1 hour rating but not really my line of work...

 

[RARWOOD]

I would have thought that you would want to apply the Plywood directly to the framing than cover it with type X GWB. Since there are published loads for Plywood over GWB it apperently is done.

I wonder if it has something to do with tested assemblies. If no one has done a fire rating test on a wood framed wall sheathed with plywood then covered with GWB, then it might be easier to cover a rated wall assembly with the plywood. I just can't see how it would be very pratical for anything but the interior face on a shaft wall. It would just seem that if the wall face was visible, that you would have to cover the plywood with GWB to finish off the wall face.