EFVM vs Flood

EFVM vs Flood

There's no question about it. Electric Field Vector Mapping® is the most reliable method in the industry for integrity testing and troubleshooting waterproofing membranes. And only ILD® has it.

How EFVM® Works

ILD®'s proprietary EFVM® test is a low-voltage method that creates an electrical potential difference between a non-conductive membrane surface and conductive structural deck or substrate, which is earthed or grounded.

A. Small electrical pulses are directed onto the membrane. The electricity is searching for a ground connection.


An electric field is created by applying water on the membrane surface and using the water as a conductive medium. A breach in the membrane creates a vector (ground fault connection), which can then be measured by a certified ILD® technician.

B. If the membrane is watertight, the electricity is isolated and does not find a ground connection.


The EFVM® technician reads the electric flow traveling across the membrane, mapping the "vectors" with pin point accuracy. What better way to get peace of mind when it comes to the integrity of your waterproofing membranes?


Flood Testing

  • ILD® technicians use EFVM® testing to locate membranes breaches
  • Flood testing can neither locate breaches, nor verify the absence of breaches
  • EFVM® requires as little as a spray of water or existing water within the overburden to test waterproofing
  • May actually cause more damage with membrane breaches from the required amount of flood water
  • EFVM®'s technology can be used on flat, sloped and vertical surfaces
  • Sloped or vertical surfaces cannot be flood tested
  • Testing can occur after all work is completed and overburden is installed    
  • Expensive and time-consuming
  • Any breach allowing even minute amounts of water will conduct electricity to complete a circuit, measurable by the ILD® technician
  • Pinholes and minor seam voids escape flood testing detection
  • The EFVM® system gives measurable and accurate readings from a potentiometer
  • Prone to limitations of human perception of water leaks
  • The contractor can repair the defects found and have them retested the same day
  • Water infiltration damage from flood testing often restrains retesting
  • EFVM®'s non-destructive method reads through all typical water-permeable overburden mediums such as soil, sand, crushed stone, pavers, asphalt, and un-reinforced concrete    
  • Garden roofs prohibit flood testing
  • Little water is needed for an electrical flow to be created
  • The additional load of the flood testing water can create structural concerns