Dry Wall Pullout Capacity

[chriskrol]

Hey guys,

I am trying to figure out what is the pullout capacity of a 1/2" dry wall attached to the stud with #8 screw. Is there any literature available?

Thanks

 

[Ron]

The drywall will not fail in "pullout" but rather "pullover" of the fastener head. In direct tension pullover, the drywall has little strength (depends on the paper facing type, thickness, etc.), usually less than 100 lbs.

In lateral shear, the fasteners fare a bit better as this puts the gypsum core in compression ahead of the fastener, this getting more out of the fastener/board interface.

 

[JLNJ]

If pullover doesn't control, my Clark catalog has 123# for a #8 screw in 18 gage material. Remember to consider prying action.

 

[UcfSE]

You can check out some manufacturer data, such as DensGlass. In their literature, they include negative pressure tests which given framing, screw size and spacing. From there you could back calculate a tension/pullover capacity for a single screw. Keep in mind it is an ultimate load, and may be applicable to that product only. Compare this allowable value with the screw capacity in the substrate. I would use a factor of safety of at least three, maybe four. Even if you can't find the particular manufacturer or type you want, this will get you in the neighborhood for a sanity check.