The roofing industry has been shifting the method of testing roof membranes for years and its popularity is growing with greater speed each year. There are two good reasons for this shift which can easily be explained for those roofing contractors that are new to this method of electronic leak testing.
First, architects today are writing specifications calling for electronic testing (EFVM and High Voltage) in both the quality control and quality assurance sections. The vast majority of new waterproof membrane installations are adapting and choosing electronic testing to be performed after a new membrane is installed as opposed to the old traditional flood testing. There are a few terms you may see such as – EFVM which stands for Electric Field Vector Mapping or you may see low voltage testing, high voltage testing, electric leak detection, vector mapping, wet method test, dry method test or ANY combination of these terms. Truth is, more and more engineers, architects, specifiers and manufacturers are calling for this technique to be used in lieu of flood testing.
The New Standard of Roof Leak Testing
The fact that this method is going to become a standard way of testing newly applied roof membranes brings us to the second reason why these professionals are making the shift. The reason is simple; it is a much more accurate test method! Fact is electronic leak testing is more cost effective, faster, less intrusive and MUCH more accurate than flooding out a brand-new roof with water and waiting for results. The results of electronic testing are being communicated live as the technician is performing the test. Repairs are then being made while the technician remains on-site. This enables the damaged areas to be re-tested and certified leak free the same day. This is absolutely impossible to do with flood testing which is an important reason this transition is taking place throughout the industry worldwide.
There are very few limitations for using the electronic leak testing method for new roof membranes but they are worth mentioning. The first limitation is if the membrane or any layer of the roof envelope has metallic properties the test will not work. An example of this is the EPDM roofing system. This system contains a carbon filler which is conductive in nature and will give off false positives while testing. Another limitation is if there is a fully adhered vapor barrier in the assembly. A vapor barrier will most likely block the water from hitting the concrete substrate after it passes through the breach in the membrane. Unless the breach has punctured through not only the membrane but the vapor barrier itself, the test will not signal the technician and the breach will be missed. The last and most important limitation is that the roof substrate must be conductive. This means that wood frame buildings or any non-conductive substrate will not complete the necessary circuit needed to detect a breach. Electronic testing can be done on non-conductive substrates only if a layer of conductive mesh (such as ConDuct® Mesh) is installed into the assembly above the substrate before the waterproof membrane is installed.