Figure 4.2.8 shows another case of insulation attachment failure (Quirouette 1989). In this case,
the insulation was simply spot adhered to the polyethylene air barrier/vapor retarder which was
attached to the top of the wall studs and the top of the parapet top plate. The insulation/
polyethylene was not adequately supported to withstand the wind pressures, and eventually it was
displaced and tore.
Detachment of air
barrier and rigid
insulation due to
Figure 4.2.8 Insulation Attachment Failure
Given a well-attached insulation material, the concern over thermal bridges remains. Thermal
bridging is not given much attention in existing construction guidance documents. In fact, these
documents contain many examples of thermal bridges in their recommended design details.
NCMA-TEK No. 151 is an exception, showing several examples of thermal bridges in masonry
walls and pointing out the advantages of cavity insulation for avoiding such problems. Thermal
bridges are discussed below in the section Examples and Details.