Posted By grafftl on 26 Sep 2018 05:28 PM
Home in North Carolina has brick siding with small space between it and frame inside wall. This creates a void that runs from crawl space to attic, possibly allowing vermin to traverse between the two. Foaming top and bottom is an option, but that would eliminate possibly valuable airflow from the crawl space, maybe making it less desirable? Advice welcome.
The air gap between the brick veneer and the framed wall sheathing is a necessary capillary break and drain space for moisture that blows by the brick during a rainstorm. (It's almost shocking how porous brick veneers really are!) Ideally the brick veneer would be vented to the outdoor at both the bottom (weep holes every 18-24" along the bottom course), as well as at the top (with a corresponding set of holes near the top course of brick), and NOT open to either the attic or the foundation crawlspace, but historically some builders have done one, the other, or both. Both can usually be rectified, but not before adding the venting top & bottom. With vents at both the top & bottom temperature differences between the outdoor air and the interior wall will generate a convection force to slowly move outdoor air through that path and drying it out.
Vented crawlspaces in an NC climate are a bad idea in general, and will usually bring more moisture into the crawlspace that it purges. A ground vapor barrier well sealed to the walls and R10 rigid insulation, sealing off the vents is better for keeping the moisture content of the joists & subfloor lower in almost every case.