When reading the "Woodframe Envelopes in the Coastal Climate of British Columbia, Best Practice Guide Building Technology" put out by CMHC, 2001, it's very interesting that in Figure 3.1: Effect of overhang on wall performance, in Chapter 3 (Controlling Moisture Sources) claims that for exterior walls without an overhanging roof, 88% of these walls have moisture problems!! However if the roof overhang is 600mm (roughly 2 feet) or greater, the percentage of exterior walls having problems drops to 25%. Apparently these stats come from the Survey of Envelope Failures in the Coastal Climate of BC.

In Vancouver and the lower mainland, nothing has been done to change any builing codes to avoid all the leaky condos that are still getting built. My question is why?