Please note that this is a scanned copy of a paper originally published in 1988, so the text is not as clear as in documents created as pdf files.

During the winter of 1983/84, the number of reports of rain penetration of insulated cavity walls seemed unusually high. A survey carried out by BRE, collaborating with BBA, BEC and NHBC, confirmed an increase, concentrated in places where exceptional weather had been recorded. In nearly every case there was also a construction or design fault which was, or may have been, a contributory or casual factor.