Last month, JLC traveled to the job site in Blue Hill, Maine, to see a panelized Passive House wall package being set up on site by the Belfast, Maine, company EcoCor (click here for last month's slideshow). Those were the walls — but what about the roof?
According to EcoCor owner and technical director, Chris Corson, EcoCor has invested in a 50-foot framing table that will let the company build roof panels on a design similar to their concept for wall panels: an inner air-tight assembly made with dimensional lumber and sealed with OSB taped at the seams, married to an outer I-joist frame that can be packed with dense-blown cellulose.
But that panelized cathedral roof system is the plan for the future. For the current job, EcoCor built a truss roof the old-fashioned way, booming in trusses one by one and stiffening the structure with 2x4 diagonal braces. Then the crew attached highly permeable Pro Clima Solitex Plus weather-resistive barrier membrane to the top of the truss chords, taping the roof membrane to the wall membrane to create a continuous wind-tight and water-tight skin for the entire shell. Then, working their way up the roof, the crew attached a cross-hatch system of strapping to the roof, making an airflow space above the membrane and creating nailing for the building's metal roofing. The result is a roof that sheds water and dries to the outside. For a closer look, click through the slideshow (all photos courtesy of EcoCor).