Interestingly, the resolution to the epidemic of building envelope failure was the rediscovery and enhancement of basic water shedding and water drainage principles.
We say ‘rediscovery’ of water shedding principles because rainscreen principles (only mandatory since 1999 in Vancouver) with cladding design dates to early Canadian Building Digest research papers from the 1960s (such as CBD-40. Rain Penetration and its Control originally published April 1963). Unfortunately, without being mandated by Code, these practices were sparingly used.
BCBS has had the opportunity to investigate and repair buildings constructed in the early 1970s where rainscreen, drainage-cavity principles were used. These cladding systems were still very functional at 40 plus years of service, despite their age – proving that sound, simple design principles are often best.