Fenestration

An effective and durable window installation demands good airtightness and proper water management. This Report explains how the degree of airtightness and the location of the plane of airtightness of the wall-window interface affect water entry. It is the second in a series of Updates presenting results from studies of window installation details.

Satisfactory window performance demands a good product and proper installation. This Report presents results from a recent study of sill installation details for the effective drainage of inadvertent water entry at the wall-window interface. 

Residential housing design continues to move toward the development of high-performance sustainable building systems. To be sustainable, a building must not only be efficient and durable but also economically viable. For these reasons, new methods of enclosure design have been examined that provide high thermal performance and long-term durability and also reduce material use (including waste), simplify or integrate systems and details, and potentially reduce overall initial costs of construction.

When insulating a steel-framed exterior wall in cold climates, it is usually necessary to provide continuous insulation on the exterior of the studs to reduce the effect of thermal bridging. As energy codes continue to become more stringent, the thickness of the continuous installation has increased. The increased insulation thickness, however, introduces several problems for building designers, such as window and door jambs needing to be extended, siding manufacturers’ warranties being voided when more than one inch of continuous insulation is used, and heavier siding products ca