Fastener length for strapping
I finished installing a plywood ceiling air barrier directly onto the bottom of 24″oc trusses (ring shanked nailed) and I’m going to be installing 1×4 strapping at 16″ oc to hang the drywall. What length of screw would be long enough to secure the strapping thru the plywood (1/2″) and into the truss? I’ll be installing 1/2″ drywall. I’m thinking 3″ screws but not certain.
What about the 3/4″ gap the strapping creates, is it best to just leave that air gap empty between the plywood and the drywall? I don’t really need the gap for wiring as the ceiling lights will be surface mount.
Also are 1 1/4 ” srews sufficient to attach the drywall to the 16″ oc strapping?