9.13.2.5. Moisture Protection for Interior Finishes
Excess water from #cast-in-place #concrete and ground moisture tends to migrate toward interior spaces, particularly in the spring and summer. Where moisture-susceptible materials, such as #finishes or #wood members, are in contact with #foundation walls, the moisture needs to be controlled by installing a moisture barrier on the interior surface of the foundation wall that extends from the underside of the interior finish up the face of the wall to a point just above the level of the ground outside.
The reason the moisture barrier on the interior surface of the foundation wall must be stopped near ground level is to allow any moisture that finds its way into the finished wall #cavity from the interior space (through leaks in the air or vapour barrier) to diffuse to the exterior. If the vapour #permeance of #dampproofing membranes or coatings exceeds 170 ng/(Pa·s·m2) (3 perm), the moisture barrier may be carried full height. If their #vapour #permeance is less than 170 ng/(Pa·s·m2) (3 perm), there is a risk of #moisture being trapped on the interior surface of the moisture barrier. The permeance limit corresponds to the lower limit for breathable building membranes, such as asphalt-impregnated #sheathing paper.
Quoted from Illustrated Users' Guide - NBC2015
#moisturebarrier #foundationwall #interiorfinish #sheathingpaper
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