How to Achieve Grade 1 Insulation

[@johnwhite2576]

What you don’t need an air barrier at the basement sill joist area? That seems very odd with climate zone do you live in this is one of the most vulnerable areas in houses north of the mason Dixon line

[@Southern_Energy]

That is correct, code and most energy efficiency programs do not require an interior air barrier in the band joist at basement or between above grade floors in CZ 3-5. It is very important that the exterior band is air sealed before the insulation goes in for best thermal performance and infiltration reduction. Band joists and cantilevers are an excellent applications for open cell spray foam which creates it's own air barrier.