Vermonter,
The foam is not a vapor barrier. Any concrete below grade is exposed to 100% relative humidity in the soil. Properly consolidated concrete that is over 5000 psi is considered impervious to water according to the ACI and PCA. I like to add Flyash and Slag to my concrete, they reduce the capillary effect that can occur. There are other additives you can put right in the concrete mix that "water proof" or "damp proof" your concrete. But the truth be told unless you are building in a total swamp, with standing water on you footings all the time, chance of an issue is remote. I build in a part of the country that gets rain 9 months out of the year and we have springs, seeps, and swamps everywhere.
ICF Contractor |