I’m building a home in central Maine (climate zone 6) and as the weather gets colder, I’m looking to insulate the building as soon as possible. The attic floor will get 18″ of blown-in cellulose and the walls are getting 2×8 Rockwool batts.

We’re closed in but haven’t framed the interior walls on the second floor. We’ve roughed in the first-floor electrical and are moving on to the 2nd-floor exterior walls and ceiling.  I’m looking to insulate the attic floor next. I’m wondering if installing reinforced 6 mil poly and strapping to the bottom chords on the trusses will be enough to hold in the attic insulation (about 2 lbs/sq ft). 

The trusses are 24″ OC and I was planning to strap at the same spacing.