Exterior Insulation
The wall insulation is foil-faced foam insulation designed for exterior installation. Before installing the the insulation we attached nailers on the outside of the sheathing, at the same height as the window nailers. We also installed nailers across the top and bottom of the walls to sandwich the insulation.
We cut the insulation to fit between the nailers and taped the seams. This is not the ideal way to install exterior insulation, as the 2×4″ nailers act as a thermal bridge, but this is how the plans called for it to be installed so we followed the instructions.
House Wrap
Installing the house wrap was a four person job, with my parents coming out to assist with rolling the wrap around the entire house while PR and I secured it with staples.
We were able to cover most of the house with just a single wrap around the structure and only had to go back to attach separate portions to cover the two gable ends. We taped all of the seams with Tyvek house wrap tape.
Roofing Underlayment
Once we installed and taped the house wrap, PR got back up on the roof and installed the roofing underlayment. Following recommendations from SK Lumber, our building materials suppliers, we used foil-faced double bubble insulation as the roofing underlayment. With an air space between the underlayment and the metal roofing, the double bubble serves as insulation above the roof sheathing, which should help reduce condensation issues in the roof sheathing.
