Frequently Asked Questions

Frequently Asked Questions

Is EFVM® leak detection suitable or conclusive on vertical applications?
The EFVM® test is suitable for vertical wall testing. Depending on the height of the wall the technician can detect breaches from either the perimeter conductor wire or can create a “picture frame” of the conductor wire to perform the test. There is no need to bring additional equipment to the site to perform an integrity test.
When performing an EFVM® commissioning test on the membrane does it include wall and projection flashing as well? Some have suggested that only high voltage is suitable for this.

During the initial test our technicians include wall and projection flashings with the low voltage EFVM® test. For projection flashing is it important that the membrane is also extended vertically.

Others have claimed that they are the only ones that can test black EPDM. Is this true?

It is not true. Although EPDM is a conductive membrane and therefore not suitable for any electronic test, ILD has been testing EPDM membrane systems for well over 15 years. If the black EPDM membrane is adhered with an “insulating” type of adhesive, then the EFVM® test will perform in locating breaches in the membrane.

Are there FM ratings on the VMG placement below the membrane?

Yes, check the RoofNav website ( for wind uplift ratings. The material name is “grounding screen” in the roof composition ratings.

How current is ILD EFVM® equipment?
EFVM® technology was developed in the mid 1970’s, and in late 1990 ILD brought it over from Germany and adapted it for the North American market. We periodically tweak the equipment to enhance performance for bare membrane and troubleshooting testing. Just as the automobile of today was founded on technology invented in 1886 but continues to evolve and improve over time, so it is with EFVM® technology.
Others claim that they can test twice as much as ILD and EFVM®. Is this important?

Speed is not important for integrity testing. The most important factor is locating any and all breaches in the roof or waterproofing membrane. The amount of square footage that can be covered in a day is dependent on the number of breaches that we locate.  Since we introduced the low voltage method to the North American market in 2001, we have never been on a project where the contractor insisted that we test faster. Their primary interest is always to ensure that ILD delivers a breach-free roof or waterproofing membrane for their client.