Roof Testing types

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Author Message Robin E. Snyder Senior Member Username: robin Post Number: 569 Registered: 08-2004 Posted on Wednesday, September 24, 2014 - 11:32 am:    Can anyone summarize the pros and cons of various roof testing methods, particularly flood, EFVM and infrared? ken hercenberg Senior Member Username: khercenberg Post Number: 826 Registered: 12-2006 Posted on Wednesday, September 24, 2014 - 12:50 pm:    Flood: Imposes loads that may or may not be allowed for in structural design. Flooding can result in leaks and can destroy your roof system so a minor error can result in a complete tear-off. Infrared: Tests for differences in temperature. While these differences are often attributed to the presence of water in some locations, that may not be the case. Additionally if water has entered and migrated, the location of the water may have nothing to do with the location of the leak. Electronic Mapping: While this won't work with some forms of single-ply, most notably black EPDM, I have found this to be the most reliable but also the most expensive (short term). There are a couple of different forms of electronic mapping. EFVM is a brand name of sorts promoted by one testing agency. Still, it is pinpoint accurate in finding leaks in the field of most roof membranes. In the case of PRMA/vegetated roof systems, you can leave the wires in place and come back in the future to determine the location of damage that occurs after the overburden has been placed. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1595 Registered: 03-2002 Posted on Wednesday, September 24, 2014 - 04:12 pm:    EFVM also has the plus that - because the conductive layer needed to make it work is embedded in the roof system - it can be done over again in the future at a much reduced cost over the first time installation. Robin E. Snyder Senior Member Username: robin Post Number: 570 Registered: 08-2004 Posted on Wednesday, September 24, 2014 - 04:13 pm:    Given the choice between flood and infrared, what would be the general preference? John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1596 Registered: 03-2002 Posted on Wednesday, September 24, 2014 - 05:21 pm:    Infrared only works to show where there are leaks, if they've actually leaked. This is because it shows heat differentials present because of escaping heat. In some climates or weather conditions, where there is not enough heat differential, it may not work real well. Flood testing is problematic because leaks may not show up in the limited time it is underway. In addition, with 1/4 inch slopes, it can be maddeningly hard to create dams delineating test areas that will allow the entire roof to be tested. You usually can't put enough water on the roof (unless it's small) to test the high points because of the weight. My preference for the best results in careful observations at key points during installation by experienced personnel. I have often specified, in addition, inspection by the membrane manufacturer's personnel. That does have a cost, but can be useful. ken hercenberg Senior Member Username: khercenberg Post Number: 827 Registered: 12-2006 Posted on Wednesday, September 24, 2014 - 10:29 pm:    I agree with John. I've found that having full-time compliance inspectors, even if they have little idea what they're doing, tends to result in better installation. If you really have to choose between the two, depending on conditions I'd probably lean towards IR. Like the medical mantra says "First do no harm".