How do i isolate a in p=a+b+c?

I have a old house(1959), I want to isolate the basement. I chooses to use 2 inch blue polyterene panel... .?

• When i bought the house, the inspector told me if i want to isolate this old foundation. i would have to let this foundation breath by do not totally isolate. He told me to let about 2 feet from the basement ground free of isolation. Is it ok to let the old foundation breath by do not completely isolate the foundation by letting 2 feet from the basement ground not isolated?

• Answer:

  Yes I would say that would work perfectly perhaps even one foot would be enough unless you have water problems at the base of the foundation then stick with the two foot deal.