Wood Three Hour Fire Assembly
Is it possible to construct an assembly for ceiling between first and second floors using 2x with few layers of gypsum to obtain a 3-hour fire rating?
There are no three-hour rated wood assemblies. That kind of rating requires concrete construction. We have listings for several one-hour assemblies and a two-hour assembly. They are available in section 17a and section 17b of SBCA’s Metal Plate Connected Wood Truss Handbook. For additional listings and information on fire-resistance rated assemblies see SBCA Research Report 1509-01: Fire Resistance Rated Truss Assemblies.