Contractors Nicole Tysvaer and Matt Kulp of Symbi Homes have made a decision regarding roof ventilation at their Model ReModel 2022 in-law suite addition.
The remodelers had been debating two options for insulation at the vaulted ceilings of their newly constructed Zero Energy Ready structure:
(1) Open- or closed-cell spray foam to completely insulate and air seal an unventilated roof system; or
(2) Insulate with dense-packed cellulose and maintain a natural "stack effect" ventilation system via soffit and ridge vents.
Stack effect ventilation (or chimney effect) refers to the natural movement of air resulting from changes in air pressure, temperature, and density levels. This occurs when warm air inside a building rises, pressurizing the top of the building and pushing that warm air out while pulling in cold air at the bottom, for example.
The Symbi team chose option #2 and selected Greenfiber's Sanctuary cellulose product for the ceiling insulation.