December 12th, 2017
the joints between windows (or doors) and the structure of buildings are without doubt the most delicate and the most vulnerable.All too often, this is where the first signs of deficiencies in the building envelope appear. Poorly designed and prepared joints, which mean improperly installed doors and windows, can cause several major problems.These include: • infiltration and exfiltration of air and sound • condensation which can result in toxic molds and cause major degradation of the envelope • rain seepage • reduction in insulating capabilities • discomfort • increase in heating costs • deterioration of interior finishings The quality of window installation ranges quite significantly from one site to another.The essential nature of the wall air barrier system, particularly the connection between windows and the structure itself, is often misunderstood and improperly incorporated by building designers and builders. However, if the Canadian window installation standard (CSAA440.4) published in 1998 is followed, effective joints can be designed to last for the effective useful life of the building envelope, for example, for more than 25 years. It would certainly be in the interest of window manufacturers, building designers and even window installers to obtain a copy of this document, which is about 100 pages long, to offer better service to their customers.Though there are general principles which apply, including air barrier integrity, there is no easy and universal method of installation that applies to all types of windows.