Sizing Metal Studs For Residential Sheet Rock Ceiling

Wow, Studs on the ceiling, iquess you need to first look up the definition of a stud.

may be good for some info on steel joists (as well as studs).

The drywall thickness will probably be dictated by fire protection requirements rather than structure. Check with the Gypsum Association http:/
Their "Fire Resistance Design Manual" contains some assemblies which use cold rolled steel members.

Residential dry wall ceiling are typically one layer of 5/8" fire resistant sheetrock for one hour fire protection and two layers if a two hour protection is required (for an apartment up stairs).

The joists are usually 33 kpsi, 2"x6" in none load bearing cases.