Conclusion
Photo courtesy National Research Council Canada
None of the moisture-detection methods described in this article are able to quantify the moisture content without performing core samples, which is undesirable due to the destructive nature of this sampling.
For all water-detection methods, there is the potential for false positive readings. The experience and/or licensing of the operator is essential for performing the test and interpreting the results accurately. All the methods investigated are also sensitive to the type of roof assembly under evaluation.
Based on the review conducted by RICOWI’s Moisture Control and Green Committee, it is evident a generic method does not exist to detect exterior water entry into all types of roof assemblies.
A common industry practice is to employ a combination of applicable methods to both detect the presence of water in a roof assembly and identify the source of the leak. Since infrared thermography is the most simple and convenient method, it is often used in conjunction with another, more technical method to detect the presence of water depending on the roof type.
It is important watertightness evaluations are not only specified in the aftermath of a major weather event or roof leak, but also included as part of a regular maintenance program.
Without performing regular watertightness evaluations, property owners will either be left guessing whether there is a problem with their roofs or will only be made aware of an issue once it has progressed to visible interior damage.
However, by combining water-detection methods suitable for a particular roof, one can obtain reliable information on the watertightness resistance and condition of an existing roof system (Special thanks to David Hawn of Dedicated Roof and Hydro-Solutions for his comments on this article. The authors acknowledge the members of the Moisture Control and Green Committee of RICOWI for their input, especially David Balistreri of Building Envelope Consultants, Greg Keeler of Owens Corning, Peter Brooks of IR Analyzers Vector Mapping, Shaun Katz of Detec, Tom Kelly of 2001 Company, and William Tipton of Roof Maintenance Systems.).
| REFERENCES |
| 1. ASTM D7877, Standard Guide for Electronic Methods for Detecting and Locating Leaks in Waterproof Membranes. 2. ASTM D7954, Standard Practice for Moisture Surveying of Roofing and Waterproofing Systems Using Non-Destructive Electrical Impedance Scanners. 3. The paper “Climate Change Adaptation Technologies for Roofing” by B. Baskaran, S. Molleti, D. Lefebvre, and N. Holcroft for the 33rd RCI International Convention and Trade Show. 4. “Electronic Leak Detection: Sound Science, Not a Magic Wand” by P. Brooks in the July 2017 issue of RCI Interface. 5. Testing Application Standard (TAS) 126-95, Standard Procedures for Roof Moisture Surveys. 6. “Electronic Leak Detection: A Quality Assurance Tool” by D. Honza for RCI Interface. 7. Infrared Roof Moisture Surveys Accurate Assessment of Roof Condition. Visit www.iranalyzers.com/infraredroof.htm for more information. 8. Nuclear Roof Moisture Surveys. Retrieved from IR Analyzers Vector Mapping at www.iranalyzers.com/nuclearroof.htm. 9. “A Comparison of Three Different Technologies for Performing Nondestructive Roof Moisture Survey” by J. Robinson, D. Bradford, J. Mitchell, and P. Majkowski, published in the Proceedings of the North American Conference on Roofing Technology. 10. The American National Standards Institute/Single Ply Roofing Industry (ANSI/SPRI)/RCI NT-1, Detection and Location of Latent Moisture in Building Roofing Systems by Nuclear Radioisotopic Thermalization. |
Dominique Lefebvre is a research officer with the National Research Council Canada (NRC). Her research area focuses on the evaluation of the interface of various roofing materials, as well as the development of tools and techniques for climate adaptation of commercial roofs. Currently, she is working on developing the performance requirements of coverboards in low-slope membrane roofing for the creation of a harmonized standard. Lefebvre can be reached via e-mail by contacting at dominique.lefebvre@nrc-cnrc.gc.ca.
Bas A. Baskaran, PhD, P. Eng., is a group leader at NRC, where he researches the performance of roofing systems and insulation. He is an adjunct professor at the University of Ottawa, and a member of Roofing Committee on Weather Issues (RICOWI), RCI Inc., Single Ply Roofing Industry (SPRI), and several other technical committees. Baskaran is a research advisor to various task groups of the National Building Code of Canada (NBC). He was recognized by Her Majesty Queen Elizabeth II with a Diamond Jubilee medal for his contribution to fellow Canadians. Baskaran can be reached at bas.baskaran@nrc-cnrc.gc.ca.
