Re: Plastic needed under foundation slab? those half blocks could present a problem in the frost line, if water/mud get in there and freeze they will break your footing. Do what you can to seal those. There are many experienced on this sight that may have a solution on how. Good luck
Gareth
__________________ We do not inherit the earth from our ancestors; we borrow it from our children. In Wilderness is the preservation of the World. - Henry David Thoreau |