To manage air leakage, possibly the best solution is
the exterior sheathing approach utilizing the exterior sheathing, self-adhesive membrane strips and
sealant to achieve an effective air barrier system.á This
system is easier to detail since there are far fewer penetrations and
intersecting elements.á The need for interior sealant in conjunction
with the polyethylene is eliminated.
For vapor diffusion,á
the function of air barrier, moisture barrier and vapor retarder can be
integrated into a single element,
such as self-adhesive membranes.
All penetrations through wall and roof assemblies must
be appropriately detailed to maintain continuity of the basic function or the wall assembly.á Mechanical and electrical penetrations are
of particular
concern.á Trades in these systems
usually have little knowledge of what is being attempted in the envelope construction.á Details must be developed with the
mechanical and electrical
designer to ensure air tightness of these penetrations.