I was just told that Gypsum Association GA-216 now requires impact-resistant gypsum board to have 33 mil (20 ga. for dinosaurs like me) structural (not drywall) studs, which would be a substantial cost increase. What is the difference between structural studs and drywall studs? I always thought it was just the thickness and where they were used.
Looking through GA-216-13 (available to view for free here from the Gypsum Association: https://www.gypsum.org/publications/view-only/application-finishing-gypsum-panel-products-ga-216-13/), I didn’t see anything that would indicate impact-resistant board be applied to any particular thickness of stud.
They do note however that steel framing members from 0.033 inch to 0.112 inch shall comply with ASTM C 955 which is for load bearing studs. But that would apply anyway, regardless of what type of board is being fastened to it.
Is there a more recent update than from 2013?
Guest,
Yes there is a new GA-216-2016 publication.
https://www.gypsum.org/2016/01/gypsum-association-releases-revised-application-standard-ga-216-2016/
I have not seen this publication.
This may be to do with screw holding capabilities. This has been a requirement (or at least a recommendation) for cement board substrates for some time. It does cost more of course, but depending on the situation maybe not. For example, with some projects I did the stud heights were such that we already were at a higher metal thickness to reach deflection limits.