Overview of Approach

The question of fault tolerance in jointing systems has not yet been broadly explored and the approach taken in this study provides some fundamental in­formation on the nature of water entry at joints. In this paper, information is provided on results from a laboratory study on the weathertightness of vertical and horizontal joints of a simulated wall system when subjected to water pen­etration tests in which test conditions emulate heightened wind-driven rain loads. An account of the experimental program is provided that includes a summary of the approach, and a description of the test apparatus, specimen, methods, and parameters. Thereafter, results of watertightness tests on both vertical and horizontal joints are given in terms of the rates of water entry across the sealed joint in relation to simulated wind-driven rain loads. The discussion focuses on the nature of entry through openings of deficiencies of the jointing product and the function of the backer rod in providing a water­tight seal.