February 2006

Water, water everywhere

Water, water everywhere 5 stars5 stars5 stars5 stars5 stars

Flood testing is appropriate only for waterproofing systems

by Joan P. Crowe, AIA
1 person has posted a comment

There are various occasions when roof system specifications call for flood testing, such as to determine quality assurance of a newly installed roof system or locate a leak source. But sometimes, flood testing is recommended when it isn't appropriate. Following is a discussion about NRCA's guidelines for flood testing.

Not recommended

NRCA does not recommend conducting flood tests as part of a routine quality-control or quality-assurance program for a new roof system. One reason is flood tests sometimes are solely and incorrectly relied on to determine roof system quality. Flood testing alone does not forecast a properly designed or installed roof system. For example, a flood test will not provide information about service life or evaluate a roof system's ability to resist wind or impact loads.

Flood testing also is not appropriate for identifying potential leak sources. Roof systems are designed to be weatherproof, not waterproof. A weatherproof roof resists the passage of water with a minimal amount of hydrostatic pressure (flowing water); waterproofing systems prevent the passage of water under hydrostatic pressure (standing water). For example, water leakage may occur at roof drain flashings with flood testing. Flood testing exposes roof drains to hydrostatic pressure, and roof drains are not designed to be leak-free under such unrealistic...

To read the article in its entirety, please log in or register (registration is free).

Log in or register for FREE access to this article and other Professional Roofing online content.

Not a professionalroofing.net user?

Register now for free access
  • Full access to every article
  • Online Web exclusive information
  • Photo gallery
  • Breaking news
  • Online classified ads

Already a professionalroofing.net user?

Log in now

User name:



Login help
Click here to have your user name and password emailed to you.

Comments (1) Login to post a comment or rating

Posted by patrick k on 5/23/2013, User rating 
not ratednot ratednot ratednot ratednot rated
Report Abuse
a minor correction, "hydrostatic" refers to standing water, "hydrodynamic" refers to flowing water conditions.