This paper summarizes the most recent results from an ongoing, multi-year research program to monitor the long-term performance of residential air barrier systems. Airtightness tests were conducted on I 7 houses, located in Winnipeg, Canada, ranging in age from 8 to I I years, for which there was extensive historical data. Eight of the houses used polyethylene air barrier systems and nine used an early version of the airtight drywall approach (ADA). The latest tests were conducted in 1997.
Whole-house tests were developed to compare the airflow resistance of several different materials used to seal the walls of a house at the outer surface. These airflow resistances were measured infield installations and include the effects of interactions with adjacent materials and assemblies. The materials tested were housewrap over fiberboard and foam sheathings, extruded polystyrene foam sheathing with the edges taped, extruded polystyrene sheathing with the edges untaped, and caulking and foaming the inside of the wall cavity.
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.
Good airtightness of a building can be achieved by the incorporation of an inner sealing layerfor the exterior walls and roofs in the form of a plastic film, which also serves as a vapourbarrier. However, if it is not wished to use plastic film as an inner sealing layer, thenairtightness must be effected through the use of other materials or in some other way. Thisproject has been concerned with investigation of a number of alternatives.
Use of Brick Veneer/Steel Stud wall systems has preceded adequate forma} scientific investigation into its long term serviceability and safety. Of particular interest to many parties is the performance of the wall system under typical winter conditions encountered in cold climate regions of Canada. In this study, experimental investigations of three types of Brick Veneer/Steel Stud wall systems were performed using a specially built apparatus used to provide air pressure, temperature and vapour pressure differentials across test specimens.
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