# 1 Hour rating on a shear wall



## Moe (Aug 22, 2014)

Newbie to the forum. Has anyone had any experience with fastening GWB over structural shear panels with the attachment being into the panel itself, not the studs behind? The manufacturer of the GWB states that screws into the sheathing itself is sufficient, but the inspector says I must show him a tested assembly. It is a WP-3242 wall assembly with 2 x 6 framing with fiberglass insulation, RC channel on 1 side, 15/32" sheathing on opposite side with 5/8 GWB over both. Since the shear is taken by the sheathing, it is my belief that attachment into the sheathing is sufficient as the screw pull out table on the sheathing is approximately 5 times that of the RC- Any help would be greatly appreciated


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## fatboy (Aug 22, 2014)

Welcome to the forum.........don't have access to the Gyp manual right now, I'm sure someone will come up with it........


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## north star (Aug 23, 2014)

*~ | ~ | ~*

Moe,

Also, ...Welcome to The Building Codes Forum !  

Your Inspector is correct !...........The manufacturer' instructions rule over the codes.

Does your GWB manufacturer have an actual, approved, tested assembly to submit

to you ?.......If not, then the rules of the IBC apply to the attaching of the GWB.

*~ | ~ | ~*


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## cda (Aug 23, 2014)

If you are trying to achieve a one hour assembly

Welcome welcome

I would also want a detail showing a listed tested assembly.

So if you can find one with the method you are trying to do, should be good to go.

What building code and edition is this project under ???

There is also the cook book method

Ibc 2009

Read all of

721,

721.2.1.4.2 Fire-exposed side


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## MASSDRIVER (Aug 23, 2014)

Why not just cut and screw the drywall on the stud lines? Use a 2" screw.

Brent.


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## north star (Aug 23, 2014)

*~ - | - ~*





> "Why not just cut and screw the drywall on the stud lines? Use a 2" screw."


Respectfully, but which code section, or approved assemblydoes this suggestion come from ?.....................The OP mentions

a 1 hr. fire rating.



*~ - | - ~*


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## MASSDRIVER (Aug 23, 2014)

I admit a s s uming.

It sounds like the problem is the screws anchoring only on the ply, not directly to stud. Like screw it anywhere you want.

If you just pretend there is no ply, and anchor into the studs, using longer screw for adequate embedment, it seems you now meet the fastening requirement into studs.

Open to correction from super smart code expurts.

Brent.


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## Moe (Aug 23, 2014)

Yes, the problem is there is not a tested assembly that exactly describes what I am doing- There is an assembly for a SIP system that allows srews in just the OSB, as there is no framing except for top and bottom plate. There is also an assembly that allows GWB to be attached over fiber or mineral board(Sound board) broke between the studs and screwed to the sound board with type G (Gyp) screws, which to me sounds ridiculous. The manufactures association for OSB (Engineered wood association) states that  the IBC and 3 of the model building codes permit determination of fire resistance by calculation as an alternate to tested assemblies.


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## cda (Aug 23, 2014)

Moe said:
			
		

> Yes, the problem is there is not a tested assembly that exactly describes what I am doing- There is an assembly for a SIP system that allows srews in just the OSB, as there is no framing except for top and bottom plate. There is also an assembly that allows GWB to be attached over fiber or mineral board(Sound board) broke between the studs and screwed to the sound board with type G (Gyp) screws, which to me sounds ridiculous. The manufactures association for OSB (Engineered wood association) states that  the IBC and 3 of the model building codes permit determination of fire resistance by calculation as an alternate to tested assemblies.


Cookbook method

Ibc 2009

Read all of

721,

721.2.1.4.2 Fire-exposed side


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## mtlogcabin (Aug 23, 2014)

http://www.gypsum.org/wp/wp-content/uploads/2011/11/GA-600-12.html

Page 9 note 23

Screws need to be longer and attach into the studs


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## mark handler (Aug 23, 2014)

mtlogcabin said:
			
		

> Page 9 note 23 Screws need to be longer and attach into the studs


Text from GA-600 fire resistance design manual



> .....When such panels are applied under the gypsum board or between layers of gypsum board the length of the fasteners specified for the attachment of the gypsum board applied over the wood structural panels shall be increased by not less than the thickness of the wood structural panels.....


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## mtlogcabin (Aug 23, 2014)

Thanks Mark I could not copy and paste for some reason


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## mark handler (Aug 23, 2014)

mtlogcabin said:
			
		

> Thanks Mark I could not copy and paste for some reason


I have that problem, I take a pill for that


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