by A.H.P. Maurenbrecher

lapse depends on the number and location of ties that have corroded, on the loads on the cladding and on the presence of other lateral support for the cladding. Other contributing factors include an insufficient number of ties, poor installation of ties and the use of inappropriate ties. Environmental, Design and Workmanship Factors Environmental conditions that contribute to corrosion include: . Wetting. The frequency and the length of time that the wall is exposed to moisture have the greatest impact on the degree of corrosion that will occur. Without moisture (e.g., in the form of water, dew, high humidity, etc.), corrosion does not occur. Buildings located in more severe drivingrain zones and the higher parts of buildings, such as parapets and corners, are most vulnerable. The CSA standard on masonry connectors includes a drivingrain index map, which gives a rough indication of areas of the country where cladding is likely to be wettest. . Pollutants. Sulphur and nitrogen oxide