Summary: In 1988, the Ministry of Transportation monitored the thickness of waterproofing membrane placed on bridges under its authority, as well as the quality of the membrane. Membrane thickness is controlled by an end result specification (ERS) that was introduced in 1986. This specification was expanded in 1987 to include membrane quality. This report contains a summary of the data assembled and comments on the level of compliance with specified tolerances. Comparison is also made to data of previous years. As a result of an analysis of the contained data, it is concluded that membrane thickness and quality compliance is continuing to improve under end result specifications.