What materials meet code for “flash and batt” on my ceiling?
I have an unfinished basement and I am looking to add about 5″ of insulation to fill up the joist bays on the ceiling. The bays are 7 inches deep and will soon have around 2″ of foam.
I am wondering if I would be able to fill the bays with Roxul and cover the entire ceiling with house wrap.
The reason for the roxul is that if necessary it would still be possible to access what’s in my ceiling (wiring and some pipes), without the negative effects on air quality of the fiberglass.
I understand I can trim the roxul with a knife to match my very uneven 80 year old ceiling joist bays.
Would this arrangement allow the roxul to deliver its full R value?
And would using house wrap maintain the fire retardant property of my insulation covering so I can meet code? If not house wrap, is there another insulation holding canvas material that would work?