Let's face it, many contractors simply
don't like polyethylene vapor
retarders. Drywallers don't because it
prevents gluing wallboard to studs.
Electricians and plumbers dislike poly
because it gets in the way. And many
builders are wary because it may cause
moisture problems in ceilings. Though
required by code in many jurisdictions,
poly vapor retarders often get
slashed or never get installed in the
first place.
The good news is that you really
don't need to use poly as long as you
use drywall, carefully taped and gasketed
(or other suitable materials), to
form an air barrier. In fact, there are
at least three practical alternatives to
polyethylene vapor retarders. These
are not compromise alternatives. Each
one can provide an effective