The crawl space source air duct shall be fitted having a backflow damper to forestall the entry of crawl space air into the supply duct technique in the event the procedure fan isn't running. An air relief vent to the outside may very well be installed. Crawl spaces with dampness https://crawl-space-waterproofing87542.onesmablog.com/crawl-space-waterproofing-services-no-further-a-mystery-76216612