The roof assembly with its layers of insulation, plywood roof deck, and self-adhering membrane is impermeable. The exterior walls of the house were rendered vapor impermeable by the addition of the exterior foil-faced polyisocyanurate insulating layers. However, the thermal resistance of the insulating sheathing is sufficient to stop any condensation on interstitial surfaces that might otherwise occur. A small area of the basement wall was left exposed above grade, allowing the concrete and stone structure to dry to the outside.