Do I need a conductive substrate for electronic integrity testing?

Yes. Both low-voltage wet testing and high-voltage dry testing require a conductive substrate directly below the waterproofing membrane — typically a concrete or metal deck. On timber decks, a conductive medium such as wire mesh or conductive glass felt can be installed during construction to enable EIT. See LRWA Guidance Note 18 (2025) for full substrate requirements.

Can you electronically test a green roof or buried waterproofing?

Not with standard EIT once the overburden is in place. For buried waterproofing, the correct method is electrical field mapping (EFM) — a buried leak location technique that locates membrane breaches to within approximately one metre without lifting the overburden. CIRIA C817 and the GRO Green Roof Code both recognise EIT as a pre-covering QA method and EFM as the post-burial investigation method.

What is the difference between moisture mapping and leak detection?

Moisture mapping tells you where moisture has accumulated within the roof build-up. It does not tell you where the membrane has failed. Leak detection methods such as low-voltage EIT or electrical field mapping locate the actual breach in the membrane. The two are complementary: moisture mapping identifies which areas need investigation; breach-location methods find the source.

Is flood testing safe for flat roofs?

Flood testing carries real risks. A 150mm head of water adds approximately 150kg per square metre of loading — structural sign-off is essential. Water can take many hours to manifest internally, making short test periods unreliable. Flood testing can also cause structural deflection that opens up laps and details. It has a legitimate role in post-repair verification of specific, structurally appropriate areas only.

What qualifications should a roof leak detection specialist hold?

Look for: NVQ Level 3 in waterproofing testing and inspection; RAWTA membership (the Roofing and Waterproofing Test Association); and a demonstrable CV in flat roofing and waterproofing systems. Under the Building Safety Act 2022, appointing an incompetent inspector carries legal liability for duty holders.

Which leak detection method works on a single ply membrane?

For QA of weld continuity at laps and details, vacuum box testing is most reliable. For field-sheet investigation with a conductive substrate, low-voltage wet EIT is standard. High-voltage dry testing also works on non-conductive single ply on conductive substrates. Black EPDM membranes are generally not suitable for EIT due to carbon black content.

How does permanent sensor monitoring differ from leak detection surveys?

Leak detection surveys are point-in-time investigations locating a breach. Permanent sensor monitoring is continuous infrastructure embedded during construction, monitoring moisture in real time and triggering automated alerts. CIRIA C817 specifies permanent monitoring for blue-green roofs; BS 6229:2025 references electronic devices for detecting leaks between inspections.

Does electronic leak detection work in the rain?

Low-voltage wet testing requires a wet surface so rain is not a problem. High-voltage dry testing requires a dry membrane and cannot be performed in wet conditions. Tramex capacitance mapping works in most weather. Infrared thermography requires dry sunny conditions. Tracer gas is best in calm dry conditions as wind disperses escaping gas.

Service

Permanent Leak Detection & Sensor Monitoring

You stop hoping the roof is watertight. You start knowing it is — because you have the data.

From investigation to certainty

A BLL investigation finds a leak that already exists. Sensor monitoring eliminates the uncertainty before the leak happens.

Vector designs and commissions embedded moisture sensors in complex roof assemblies during construction or post-completion. Sensors monitor continuously and alert when moisture levels change. you know about a problem in days, while access is still easy and remediation costs are still manageable. Not years later, when the water has already travelled and the damage is done.

This is particularly valuable on CLT and mass timber structures, where moisture ingress isn’t visible until structural degradation is already underway. It’s also the right approach for institutional asset owners who need to demonstrate proactive building safety management under the Building Safety Act.

Vector is independent — we have no sensor manufacturer to sell you, no installer relationship to protect. We specify the right system for the roof, install it, and provide ongoing monitoring with regular performance reports. The subscription model means you have continuous independent assurance for a predictable monthly cost.

Planned preventative maintenance

Sensor monitoring tells you what is happening inside the roof assembly. Biannual inspections tell you what is happening on the surface — blocked outlets, displaced ballast, failed sealants, vegetation encroachment, damage from foot traffic or plant installations.

BS 6229 Clause 8.2 requires that flat roofs are inspected at least twice yearly: in autumn, once leaves have fallen, to verify the roof is clear of debris and draining freely; and in spring, to discover and rectify any damage from winter weather. Green, blue and other specialist roofs should be inspected in accordance with the designer’s original inspection plan.

These inspections are also a condition of every major membrane manufacturer’s warranty. Without documented evidence that planned preventative maintenance has been carried out, the warranty is void. Most building owners discover this only when they need to make a claim.

Vector’s monitoring subscription includes the biannual inspections as standard. Each inspection covers the items specified in BS 6229 Clause 8.2 — ceilings for signs of condensation, external walls and soffits for movement, the roof surface and all layers of construction, perishable materials including sealants and mortars, debris accumulation, and rooftop installation mountings for waterproof integrity.

The result is a continuous, independent record of the roof’s condition — sensor data from within the assembly and physical inspection data from the surface — maintained for the life of the building.

What monitoring covers

Green roofs and landscape podium decks
Inverted and buried waterproofing systems
CLT and mass timber structures
Data centres and critical infrastructure roofs
Post-repair monitoring (verify the fix held)
New-build commissioning verification

The subscription

Sensors installed and commissioned by Vector
Continuous monitoring — alerts on change
Quarterly performance reports
Biannual roof inspections to BS 6229 Clause 8.2
Annual condition review
Manufacturer warranty compliance maintained
Predictable monthly cost
No minimum contract beyond first year

For new-build projects, sensor monitoring forms part of our Complete Roof Assurance service — a single appointment covering independent design review, construction quality assurance, sensor commissioning, continuous monitoring and planned maintenance for the life of the building.