Appropriately securing gas entry costs less than $100 if splits are small, however large foundation repair work expense in between $5,000 and $15,000. Gas sealing beginnings by injecting structure cracks with polyurethane foam or seal with flexible caulk. Sub-Membrane Depressurization Equipments cost between $500 and also $2,500 to set up. The exposed planet in crawl areas, basements, or under manufactured homes is covered with a nonporous membrane like closed poly vapor obstacle.