What Latent Defect Insurance Providers Require
Latent Defect Insurance (LDI) protects building owners against hidden defects that emerge after handover. Waterproofing failures are among the most common claims. Most LDI policies require independent testing and certification before the insurer will issue cover—and they specify what that testing must show.
The insurer wants evidence that the waterproofing system has been designed to specification, installed correctly, and tested to confirm performance before the building passes into your hands. They also want the testing to be independent: not carried out by the contractor who installed the work, and documented by someone who has no financial stake in the outcome.
Why Independence Matters in Waterproofing Testing
Contractors have an incentive to declare work complete. Designers have an incentive to say their specification has been met. Independent testing cuts through that conflict. An insurer sees a report from a third party with no interest in approval—only in accuracy—and they can issue cover with confidence.
Independence also protects you. If the membrane fails later, you have evidence that it was tested and met specification at handover. The insurer can pursue the contractor or designer, not you.
What Vector’s Pre-Handover Testing Delivers
We carry out systematic electrical impedance testing across the entire waterproofing system before handover. This detects breaches, voids, moisture ingress, and installation defects that visual inspection alone would miss. We produce a condition report that clearly states whether the system meets specification and is ready for service.
If defects are found, we pinpoint their location. Contractors know exactly what needs repair. No guesswork. No strip-and-replace of serviceable material.
Our testing is suitable for all common waterproofing types: bituminous membranes, single-ply systems, reinforced bitumen sheets, spray-applied polyurea, and hybrid systems. We test flat roofs, pitched roofs, basement structures, and external envelope systems.
How Our Reports Are Structured for Insurers
Every Vector report includes: scope of works tested, testing methodology, location of any defects found, assessment of remedial need, and a clear statement of readiness for service. We specify our qualifications and independence. We provide raw data and photographic evidence. Insurers read these reports regularly—they understand what they’re looking at.
The Timeline
Pre-handover testing should happen 2–4 weeks before practical completion, while contractors are still on site and can address defects without delay. Waiting until after handover is more expensive (contractors move on, fees increase) and risks the handover date.
We can mobilise quickly. Once we’ve agreed the scope and structure, we’ll schedule testing and produce a report within 10 working days of site work.
Next Steps
If you’re responsible for a building nearing handover and need to arrange independent waterproofing testing for your LDI policy, get in touch. We’ll discuss what systems need testing, when, and what the report should cover.
For more information on our testing approach, see our waterproofing design review service, our quality assurance inspections during construction, or our Complete Roof Assurance service which covers the full lifecycle from design through to ongoing maintenance. For existing buildings with leak issues, see our buried leak location and permanent leak detection and sensor monitoring services.