Electronic Leak Detection Frequently Asked Questions

What is Electronic Leak Detection (ELD)?

Electronic Leak Detection (ELD) is the most time efficient and cost effective means of non-destructive testing for roofing/waterproofing membranes on low-slope roofs.  Relying on the principles of electricity and opposing electric charges, technicians are able to identify the exact location of breaches (holes) in the roofing/waterproofing membrane.  ELD uses either no water or a light "film" of water on the membrane, depending on the conditions of the roof and area to be tested.  Many times, an area can be tested, and breaches repaired during the same day.  This eliminates the need for a waiting period as required by a flood test. 

How does Electronic Leak Detection (ELD) work?

As stated previously, ELD relies on the principles of electricity and more specifically on the properties of opposing electric charges.  The technician will use one of two methods (HVELD or LVELD) to create a positive electric charge on the surface of the membrane or protection course.  The technician will also connect to the conductive structural deck below the membrane.  With the membrane acting as an insulator, the two opposing charges remain separated.  However, a breach in the membrane will allow the opposing charges to meet and in turn ground out the testing equipment.  The equipment alerts the technician to the presence of a suspected breach in the vicinity.  It is then up to the technician to use the equipment to narrow down further the location of the breach.  When the breach has been located, it is marked on the membrane and the roofing/waterproofing contractor is notified.  

When is Electronic Leak Detection (ELD) needed?

Leaks can occur within the roofing/waterproofing assembly. Typically, it was often thought that roofs were “beyond economical repair” as pin-hole sized defects were very difficult to locate / fix, often resulting in short life spans for flat roofs. With ELD, minor defects don’t require a roof replacement since they can detect and locate issues. Accurately locating roof leaks using ELD also means that our experienced technicians are able to locate leak pathways before they are able to cause extensive damage to the membrane and internal structure.

How does it compare to other methods?

Most importantly, Electronic Leak Detection (ELD) is more time and cost efficient than other forms of testing.  There is typically no waiting period between the time a breach  is identified and the time a repair can be made.  Unlike flood tests, ELD technicians can test an area in hours rather than days.  There are also no costs for materials and labor associated with building dams.  Schedule is king in the construction industry.  Electronic Leak Detection is a vital tool that can be used to stay ahead of schedule or get back on schedule.  

Are there any surfaces that ELD doesn't work on?


Any membrane that is conductive will not allow for the necessary  insulative properties required for ELD.  This includes Black EPDM (This membrane is made with carbon black, which is conductive) and any type of metal/metallic roof coating.  Urethane based coatings and other ultra-thin waterproofing membranes are dealt with on a case by case basis.  Please feel free to contact Honza Group in order to find out if we can test a specific membrane.  If a substrate or roof deck is non-conductive (ex: wood deck) or a vapor barrier is present alternative construction of the assembly will be required. 

What happens after testing?

Once testing is complete, a detailed report and plan will be generated detailing the results of the test for the customer.  

How much will it cost?

Due to the large number of factors that affect the ability to carry out testing, it is not possible to provide a fixed cost without first discussing your inquiry with one of our consultants. We will provide you with free advice and make recommendations as to the process you should follow for your particular circumstance. Usually, ELD is more affordable than you think. Contact us to learn more.

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Low Voltage / Wet Testing  |  High Voltage / Dry Testing  |  Overburden Testing  |  Conductive Mesh Testing  |  ELD FAQs