|Conceptual Reference Database for Building Envelope Research||
Vancouver building problems, findingsSome of the key findings of the survey were:
-All the problems noted in these buildings were attributed to exterior water penetration and none were attributed to condensation of interior moisture.
-Exposure was a major factor, both in terms of orientation with respect to weather and the presence or lack of protection provided by overhangs above walls.
-While it is necessary to be cautious about drawing statistical information from the study because of the sample selection method. there appeared to be a disproportionately high number of problems with face sealed stucco systems. However, similar problems were found with other cladding systems including wood and vinyl siding.
-90% of the problems were associated with interface details (windows, balcony and exterior walkway connections, penetration through the walls for wiring, vents etc. or where elements such as handrails penetrated the cladding to connect to the structure).
-Very few of the problems were associated with the clear walls without penetrations or openings.
-The material used for exterior sheathing did not appear to be a major factor. OSB sheathings, which were more commonly used in the total sample, were used on a disproportionately higher number of problem walls with but plywood sheathing was also used in walls that exhibited major problems.
-While the sample size of walls using polyolefin membrane type sheathing paper was low, we found no indication that these membranes were better or worse than more commonly used asphalt impregnated sheathing paper.
Morrison Hershfield Limited (1996) Survey of Building Envelope Failures in the Coastal Climate of British Columbia, Research Report available from Canada Mortgage and Housing Corporation, Ottawa
Blackall T.N., Baker M.C. (1984) Rain Leakage of Residential Windows in the Lower Mainland of British Columbia. National Research Council Canada, BPN 42
Chown G.A., Brown W.C., Poirier G.E. (1997) Evolution of Wall Design for Controlling Rain Water, National Research Council of Canada, CTU No.9
Morrison Hershfield, (1999) Stucco Clad Wall Drying Experiment, available from Canada Mortgage ad Housing Corporation, Ottawa
Lawton, M.D., Dales. R.E., White J. (1998) The Influence of House Characteristics in a Canadian Community on Microbiological Contamination, Indoor Air pp 2-11
Lawton M.D. (1998), Moldy Houses - Building Science Lessons from the
Wallaceburg Project, Proceedings of the Thermal Envelopes VII Conference, ASHRAE