Is 6 Mil Poly an Air Barrier

Although 6-mil polyethylene is an excellent vapor barrier it is often a very poor air barrier.

Is Poly an air vapour barrier?

Historically, placement of vapor barriers (typically polyethylene) was on the interior wall and ceiling insulation to prevent vapor division into the wall systems during the winter months when the interior of a home is warmer than the air within the wall system.

Can a polyethylene vapour barrier act as an air barrier as well?

Products that can act as air barriers are drywall, sheathing, insulation, house wrap, even the polyethylene we normally install as a vapour barrier can act as an effective air barrier, but only if you set out with that in mind and properly seal it.