PaulJi
Member
The CGBSC 2010 requires an STC 40 for floor-ceiling assemblies between tenant spaces in a project I'm working on.
The situation is the existing building has only 3/4" T&G subflooring and Open web trusses (TJS's at 24" oc.)..without ceiling or carpet etc.
The City Plan Reviewer asked for a floor-ceiling assembly from a lab test report and would accept an assembly in the Gypsum Association's manual.
My contractor states: "I don’t understand the difference between an assembly that consists of joists with a plywood surface above and ACT below, regardless of whether it occurs at a roof or a floor. Why would the exact same assembly have a different STC rating?" in other words what is the difference between an STC rated floor-ceiling assembly and an STC rating of a ATC ceiling that one adds below a structural system with a subfloor.
Obviously the contractor would rather not provide a floor-ceiling assembly with carpet/padding/plywood or (lightweight concrete) /RC channels and drywall in addition to an ACT lay-in ceiling which by itself has an STC rating of 40.
Is this an code requirement that one could successfully negotiate with a building official?
The situation is the existing building has only 3/4" T&G subflooring and Open web trusses (TJS's at 24" oc.)..without ceiling or carpet etc.
The City Plan Reviewer asked for a floor-ceiling assembly from a lab test report and would accept an assembly in the Gypsum Association's manual.
My contractor states: "I don’t understand the difference between an assembly that consists of joists with a plywood surface above and ACT below, regardless of whether it occurs at a roof or a floor. Why would the exact same assembly have a different STC rating?" in other words what is the difference between an STC rated floor-ceiling assembly and an STC rating of a ATC ceiling that one adds below a structural system with a subfloor.
Obviously the contractor would rather not provide a floor-ceiling assembly with carpet/padding/plywood or (lightweight concrete) /RC channels and drywall in addition to an ACT lay-in ceiling which by itself has an STC rating of 40.
Is this an code requirement that one could successfully negotiate with a building official?