BCAB #1554 - Resistance to Environmental Loads, Sentence 184.108.40.206.(1)
October 17, 2001
Re: Resistance to Environmental Loads, Sentence 220.127.116.11.(1)
The project is a 3 storey wood frame building built under the scope of Part 5. It is constructed in a coastal climatic area with a design total annual precipitation of 800 mm and 3050 degree days below 18 degrees C. The exterior cladding of the building will be a conventional stucco system, utilizing Part 9 stucco prescriptive requirements . The exterior wall system does not incorporate a cavity between the stucco and the exterior wall sheathing.
Reason for Appeal
Sentence 18.104.22.168.(1) requires building assemblies to be designed to have sufficient capacity and integrity to resist or accommodate all environmental loads and effects of those loads that may be reasonably expected, having regard to the environment to which the components and assemblies are subject.
The appellant contends that stucco clad wall systems that do not incorporate a cavity have proven themselves over the years to be an appropriate system for the subject climatic conditions. The failure or success of any system to achieve successful environmental separation lies in the attention paid to details, regardless of the system. There is no requirement within Part 5 that a cavity system be provided with stucco cladding.
Building Official’s Position
The Building Official considers that for this building and its location, a stucco system that does not incorporate a cavity will not be adequate to successfully resist environmental loads. The subject building does not have roof overhangs. Further, judgments from a recent legal case implied that a stucco system that does not incorporate a cavity was in part a design that "allowed rain penetration to do its worst" and that "significant damage was foreseeable".
Appeal Board Decision #1554
It is the determination of the Board that Part 5 does not preclude any particular wall design providing the performance requirements are met.
George Humphrey, Chair