It was time to breathe new life into this old rock foundation wall. The three primary objectives were to make the wall watertight, airtight and insulated. Starting with mortar, we sealed all the gaps in the wall. This was the first step needed to keep the basement dry. While it is not common to do mortar work before spray foam, we believed in this instance for a long-lasting job the mortar would help the spray foam stick better and actually "stitch" the stones in the wall together. And in some places along the wall above grade, you could look through the wall to the outside. This obviously caused quite a bit of draft, robbing the basement of much needed warmth in the winter, and allowing warm and humid air easy access in the summer. Once the mortar work was complete, we sprayed the entire wall from top to bottom with approximately 2 inches of closed-cell spray foam. With an R-Value of about two before the spray foam, the rock wall now boasts an R-Value of 16. The cold earth on the outside of the wall will not penetrate the spary foam insulation, thereby allowing the ambient heat from the furnace to warm the otherwise unheated space. The homeowners can expect to see the equivalent in savings of 160 gallons of heating oil annually, not to mention a warmer, healthier and more comfortable home. And for a short, fun time lapse video of the spray foam being applied, click here.