In cool and cold climates, sloped roofs with cathedral ceilings are quite sensitive to moisture damages caused by built-in moisture and prolonged concealed condensation of water vapor produced inside. Conventional solutions are to leave a cavity between the thermal insulation and the sheathing and vent it with outside air and/or to include a vapor barrier below the insulation layer. An alternative, however, is the self-drying roof. This concept was evaluated experimentally.
This is a case study describing the procedures for locating, prioritizing, and repairing the causes of ice dam formation at a complex of over one hundred Northeast ski-area condominiums. The testing, performed on four typical units, was commissioned by the Owners Association to prove the feasibility of preventing ice dam formation without replacing all of the existing roofs and to determine the costs of this approach. Ice dam formation is one of the predominate problems for buildings in cold climates.
Breathing walls were installed on opposite sides of a scale mock-up model of a housing structure that was situated in an artificial climate test room. We analyzed the thermal insulation capability. heat recovery effect and indoor climate for the inflow of outdoor air across the breathing wall. The rate of heat recovery reached 30% under strong winds of up to 8 mis. Even when the ventilation rate tripled due to the strong wind, the temperature difference in the vertical direction was less than 2 K.
A field test protocol to assess the heating season energy impact of operating corridor ventilation systems was developed and successfully applied to five multi-unit residential buildings (MURBs) in Winnipeg. The protocol was straightforward and inexpensive to apply. The data analyses, done in a spreadsheet computer program, revealed a similar relationship between energy use and operation of the corridor ventilation system for all five MURBs.
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