GYPSUM BOARD SHEATING FOR WOODEN STUDS 1

[nrguades]

Is Gypsum Board Sheating Allowed For Wooden Studs? If it is, where can we get the shear capacity.

In UBC 1997, Values for allowable shear load of Gypsum Board Sheating with corresponding nail spacing is only for metal studs, thhere is no value for w00d studs. tnx

 

[boo1]

Wood Frame Construction Manual; AWC; 1996, Table 3B lists

Gypsum Sheathing Board 4x8x1/2" 11 ga Screw unblocked 7" oc panel 10oc intermediate shear capacity=100 plf

Gypsum Wall Board
1/2" thk 5d cooler nails
unblocked
7" oc panel Edges 10oc intermediate support,
shear capacity=100 plf
4" oc panel Edges10oc intermediate support,
shear capacity=125 plf
blocked
7" oc panel edges 10oc intermediate support,
shear capacity=125 plf
4" oc panel edges 10oc intermediate support,
shear capacity=150 plf

5/8" thk
blocked 6d cooler nails
4" oc panel 10oc intermediate support,
shear capacity=175 plf

blocked two layer
Baseply 6d faceply 8d cooler
Base 9" face 7" OC panel edges 10 oc IC
Shear capacity=250 plf

also listed in SSDT 10-93

 

[nrguades]

Thanks boo1 for the very usefull information but I still wonder why it is not yet adopted by the UBC 97.., I still dont know with the latest issue. Actually it makes me think twice in deciding to use gypsum board rather than plywood.

 

[Taro]

Is the building in a seismic region? Gyp shear values are available, but I personally would not rely on gyp shear walls except for very minor structures and then only if I had no other choice. Gyp board is not very ductile and ductility is important, especially if earthquake resistance is needed. I have performed many post-earthquake building inspections and gyp walls are almost always the most heavily damaged elements in the building.

 

[nrguades]

No, its not in a seismic region but the wind speed is ranging from 80 - 100 mph. On higher floor, based on calculations, have shear loads lesser than what boo1 had given above.The shear capacity of 15/32 plywood sheathing with 10d nails at 6.0 o.c is 300+ plf.

 

[JAE]

What about table 25-I in volume 1 of the UBC 97? It gives shear values for nailing into wood studs (you don't nail into metal studs, you screw).

 

[uleaum]

You can find the values listed by boo1 on pages 2-383 of voluem 2 of the 97 UBC. It's an excerp from chapter 25 on gypsum.

As to what Taro said about not relying on gypsum. Yes, plywood is stronger and is a ductile type of failure, but gypsum is stronger than most people(including the code) give it credit for. The reason the values are lower is because it is a brittle failure mechanism.

For high siesmic regions gypsum is prohibit from being used to resist earthquake forces anyway. For wind controled lateral forces it is fine material. Keep in mind though the aspect ration cannot be reduced from 4:1 like plywood can in lower siesmic zones.

 

[boo1]

JAE, shear nailing plywood to steel in common in Florida.