ABSTRACT
Few of us practice architecture in climates that are devoid of moisture. When it comes to the design and performance of building envelopes, moisture is “enemy #1”. In times when buildings were predominantly constructed of massive load bearing masonry walls, durability was of little concern. The sloped outer surfaces of the pyramids, though degraded over time, are still standing. The majority of Gothic Cathedrals are beginning to suffer the ill effects of acid rain, but otherwise are enduring. However it is not uncommon to find contemporary buildings that might only be 10 to 20 years old whose envelopes are highly degraded to the point of needing extensive repair. The problem is two-fold. Massively thick walls have given way to layered systems, where the outermost layer – the one that is directly exposed to weathering- is relatively thin. Buildings were once designed using predominantly vertical walls, with roof and cornice systems designed to protect the walls from excessive wetting. Contemporary buildings often use radical geometries that place walls at a slope, remove protective overhangs, and often blur the definition of wall versus roof and as a result, also their construction systems. Given that it is highly unlikely to revert to historic forms with their vertical mass walls, pitched roofs and overhangs, this paper will examine a range of projects with a view to establishing better practices towards appropriate material selection and detailing of contemporary projects exhibiting challenging geometries, ultimately to the end of voicing caution against the use of vulnerable materials in conjunction with extreme geometries in cold wet climates.
