Case Study: Recurring Flat Roof Leak in a Commercial Building

The Problem

A commercial property in London had experienced recurring roof leaks over a three-year period. Multiple roofing contractors had attempted repairs on at least four occasions, targeting visible damage near drainage outlets. Each repair provided temporary relief, but the leaks returned within weeks.

The Investigation

Vertex was engaged to carry out an independent investigation.

Step 1: Technical Review

Available drawings, previous repair reports and photographs were reviewed. The repair history suggested that the identified defects were symptoms rather than the root cause.

Step 2: Electronic Leak Detection

A dry ELD survey was carried out across the roof surface. The testing identified three membrane breaches — none of which had been previously identified or repaired. Two were located along a seam that had not been properly welded during original installation.

Step 3: Evidence Collection

Each breach was marked, photographed and mapped on the roof plan. Moisture readings confirmed that the insulation beneath the identified breaches was saturated.

The Outcome

The three breaches were repaired by a roofing contractor under Vertex's remediation guidance. A follow-up ELD survey confirmed membrane integrity. No further leaks were reported in the 12 months following the investigation.

Key Takeaway

When leaks recur after repair, it usually means the source has not been correctly identified. Independent investigation — rather than repeated repairs — is the most cost-effective path to resolution.