Electronic leak detection (ELD) finds breaches in a waterproofing membrane, from pinholes to poorly sealed laps, without cutting into the roof. We use it on existing roofs to trace leaks, and on new membranes before they are covered or handed over.
B1 · close-up, marked for repairLocal repair to B1–B3 by the roofing contractor, then retest the repaired areas before the paving goes down.
Where the roofing contractor repairs breaches while we are on site, we can retest the same day when conditions allow.
A waterproofing membrane resists electrical current. With a conductive path to earth directly beneath it, a charge applied to the surface escapes through any breach. The equipment picks up that signal and pinpoints the breach. It is marked, the roofing contractor repairs it, and we retest.
Insulation, metal details and the test set-up all affect the result, so we check the construction before we quote.
A brush is swept across the dry, exposed membrane, with the voltage set to suit the membrane and its thickness. Where a breach gives the charge a path to earth, the equipment alarms. The current is very small. It suits most single-ply, reinforced bitumen and liquid-applied membranes, and is often preferred on liquid systems where pinholes are a risk.
The membrane is wetted so the surface carries a current. In one common method, we lay a wire loop around the test area and pulse about 40 volts through it. The operator then follows the electric field with probes to the point where it passes through the membrane. Other low-voltage systems scan the wet membrane directly.
A dry, exposed membrane suits high-voltage testing. A wet surface, or weather that rules out high-voltage work, points to low-voltage. The membrane and the build-up beneath it have the final say: we follow the manufacturer's guidance, and on some roofs we use both.
Better to know this before you book.
If ELD is not the right test for your roof, we will say so and recommend what is.
Suitability depends on the specific product and construction, which we confirm before testing.
typical lead time and report turnaround
High-voltage testing uses a very small current, and low-voltage testing runs at around 40 volts. We mark off the test area while we work and agree roof access with your site team beforehand.
The test itself does not cut or open the membrane. Core sampling is a separate step, used only when needed and agreed with you first.
That no breaches were detected in the area tested, under the conditions on the day. The report records both, so everyone knows what the result applies to. It says nothing about areas that were not tested, and it is not a guarantee of future performance.
Yes, where the construction allows, and the best time is after installation and before anything covers the membrane. We check the build-up in advance, because the test needs a conductive path directly beneath the membrane.
The site address, the roof type if you know it and why you need it tested. We will confirm whether ELD suits the roof and what it involves.
