We have encapsulated a crawl space in Harrington, DE. We installed a CleanSpace Crawl Space Encapsulation System with perimeter drainage and drainage matting. It has a SmartSump with a remote alarm. The insulation was removed from the floor and we installed 2" foam board on the perimeter walls along with R-21 closed-cell foam in the rim joist. We also installed a Turtl Crawl Space Access System.
The floor was air sealed along with duct sealing to bring the total duct leakage under the current 2009 iecc code for new construction. The house leakage is now below average.