How Electronic Leak Detection Works
Electronic Leak Detection (ELD) is a non-destructive testing method used to locate breaches in non-conductive flat roof membranes. It works by introducing an electrical signal across the membrane surface and detecting where the signal escapes through a breach.
Two Methods
Dry ELD (High Voltage)
Dry ELD uses a high-voltage brush that sweeps across the roof surface. When the brush passes over a breach, the electrical current arcs through the membrane discontinuity to the conductive substrate below, triggering an audible and visual alert.
Wet ELD (Low Voltage)
Wet ELD requires water to be applied to the roof surface. A low-voltage current is passed through the water film. Where a breach exists, the current flows through the water and the breach to the substrate, allowing the technician to pinpoint the defect.
When Is ELD Appropriate?
ELD is most effective on:
- Single-ply membranes (TPO, PVC)
- Liquid-applied waterproofing
- Hot melt systems
- Asphalt on non-conductive substrates
ELD is not suitable for conductive surfaces such as metal roofing or bituminous felt.
What Happens After Testing?
Once breaches are located, they are marked, photographed and documented. A structured report is then produced with defect locations mapped on roof plans, photographic evidence and prioritised repair recommendations.