Crawl House Vents If, nonetheless, you cover the naked floor in your crawl house with an permitted vapor barrier materials, you solely want 1 sq. foot of vent for every 1,500 square feet of house. Translated, this code requirement signifies that you want 1 sq. foot of screened vent http://interior-designer83702.articlesblogger.com/20391117/straightforward-advice-about-factors-of-sub-floor-ventilation-fan