We watched the video multiple times, astonishing images !

How do you protect your EPS foam from any petroleum products that are in the soil or accidently get in the soil in the future? Won't petroleum eat up the EPS and compromise the foundation?

Jay, Good question. The project is located near the top of the watershed in a rural location. Contamination from petroleum is not likely. If we were building on a brownfield site with the potential for petroleum contamination, we would have no choice but
to install the EPS foam over a chemical resistant vapor barrier or other appropriate geotextile system. I do not think a traditional polyethylene vapor barrier would be up to the task of protecting the EPS from groundwater or soil contaminated with petroleum
hydrocarbons or solvents. -Skylar

Thanks for the response Skylar I think most fuel and oil containers are made from polyethylene. My reason for asking is I live in an area that was developed in the 1940's and 1950's with most homes using oil for heat. As I was buying my house in 2009,
I actively went looking for oil tank and had the tank located even though the house was switched over to natural gas in 1980. After the tank was removed, contamination was found underneath it but just below the threshhold for manditory state ecology clean
up. So the contaminated soil is still there about 5 feet underground. I am planning to protect my future passive house slab on grade foundation by using three layers of 15 to 20 mil polyethylene. One layer on the bottom of the excavation, one layer on the
top of the fill and one layer on the top of the EPS Foam. All of this will be seamless pieces and brough up above ground level. I can't imaging how you would fix a sink foundation caused by the EPS foam eroding from petroleum contamination. I enjoy read your
blog. Jay

You should check out Liquid Boot, a product made specifically for sealing over contaminated soil. http://www.radata.com/pdfs/CETCO%20Liquid%20Boot%20Brochure.pdf

Great to see such care for detail continues in the trade. Enjoy