We will be using closed-cell foam for the insulation on the River House. Originally we planned on using 2″ of closed-cell foam with 5.5″ of mineral wool batts. Next, we opted for blown-in cellulose in lieu of mineral wool. Then we switched to open-cell foam over the closed-cell base. Finally, we have decided to use 100% closed-cell foam applied to a thickness of 5 to 5.5 inches yielding an R-value of 40 for the exterior walls. Today, the insulation crew treated areas of the exterior walls that will be difficult to access once all the mechanical systems are installed. This included the vertical chase behind the stairwell and the rim board joists between the basement and first floor. In addition to having the highest R-value/inch of any product on the market, closed cell foam adds a ridiculous amount of strength to the wall structure. It was necessary to heat the interior of the house with propane heaters to ensure proper curing of the foam which went in beautifully and I am very pleased with the results. The green circles are from the openings I cut in the sheathing for the ERV vents. They are taped to the pipes I installed to keep heat in and birds out until the vent caps are installed.