Page 485 - Construction Waterproofing Handbook

CHAPTER 13

LEAK INVESTIGATION AND
DETECTION

INTRODUCTION

Whenever an existing structure is experiencing water infiltration, there are standard
measures that can be taken to determine the source of leakage and make appropriate
repairs. Investigating and pinpointing building envelope breaches does not require sci-
entific measuring or expensive equipment, and the steps required to complete an inves-
tigation are not technically difficult. By applying a few basic guidelines, determining the
area(s) of intrusion can be addressed by most anyone.
Whenever leakage is occurring, it is imperative to recognize that it is very likely that
the 90%/1% and 99% principles are contributing to create the problem. The 90%/1%,
principle as described in Chap. 1, recognizes that the majority of leakage will occur at the
terminations and transitions within the building envelope and not directly through the
water barrier or divertor systems themselves. In addition, the 99% principle recognizes
that in only 1 percent of the cases it is the material or system that will have failed or is
causing the problem, as compared to a 99 percent chance that it is related to the original
installation labor techniques.
If the leakage is attributable to causes that do follow these principles (e.g., the 1 percent
chance that it is a material failure), the cause of leakage should be so obvious that no inves-
tigation is necessary. For example, a material failure should be easily observable in the form
of material completely disbonded from the substrate, uncured material, brittle or cracked
material, or other obvious signs of failure. If, however, the cause likely falls within the prin-
ciple guidelines, then the material might have been applied too thin, transition detailing
between different envelope systems been inadequate, transitions from a horizontal to verti-
cal substrate improperly installed, divertor drainage means clogged, or a variety of other
similar problems not directly associated with any specific envelope component or system.

LEAKAGE INVESTIGATIONS

When the leakage is being caused by one of these waterproofing principles, the process in
determining the source of infiltration usually requires several important and progressive
actions. These measures determine not only the area of leakage but also the cause and con-
tributing factors that must be corrected to eliminate the infiltration completely. A leak detec-
tion process should include the following actions to adequately locate and address the
problem:

13.1
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