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.

INSIGHT

Technical Resources

Standards, research and guidance that shape how we work

Vector’s work is grounded in British Standards, industry codes of practice and peer-reviewed research. Below you’ll find the technical resources that inform our approach to leak detection, sensor monitoring and waterproofing quality assurance — from the standards that mandate permanent monitoring to the insurance codes that are reshaping construction site water management.

BS 8102:2022 — Permanent Leak Detection as a Design Requirement

BS 8102:2022 is the principal British Standard governing the protection of below-ground structures against water ingress. It is the standard that design teams, contractors and warranty providers refer to when specifying basement and podium waterproofing.

Section 6.5, Note 2 is the critical citation for Vector’s sensor business: it states that warm roof build-ups and loose-laid waterproofing systems on buried decks are only acceptable where permanent leak detection systems are employed — making sensor-based monitoring a compliance-enabling technology, not an optional extra.

The standard also requires lifetime maintenance of Type C drainage systems (Section 10.2.1.3), annual servicing at minimum (Section 10.3.2), and monitoring of pump activity changes over time — all of which support the case for continuous installed sensors rather than periodic inspection alone.

Standard: BS 8102:2022 — Code of practice for protection of below-ground structures against water from the ground | Publisher: BSI

BS 6229:2018 — Flat Roofs with Continuously Supported Flexible Waterproof Coverings

BS 6229 is the principal British Standard for the design, specification and maintenance of flat roofs with continuously supported flexible waterproof coverings. It governs how flat roofs should be designed, constructed and maintained throughout their operational life — and it contains three provisions that are directly relevant to Vector’s work.

Section 7 — Examination and testing. BS 6229 requires that examination and testing of all layers of the flat roof build-up is carried out where necessary, including the air and vapour control layer (AVCL), the waterproof layer, the thermal insulation, the water flow reducing layer (WFRL), surface protection, flashings and counterflashings. This is the technical basis for Vector’s quality assurance service — independent inspection during installation to verify that each layer has been correctly applied before it is concealed by the next.

Clause 8.2 — Inspections. The standard requires that flat roofs are inspected at least twice yearly: in autumn, once leaves have fallen, to verify that the roof is clear of leaves, dirt and debris, that outlets are not blocked and the roof is free draining; and in spring, to discover and rectify any damage due to weather. Green, blue and other specialist roofs should be inspected in accordance with the designer’s original inspection plan. Inspections should cover ceilings for signs of condensation, external walls and soffits for signs of movement, the roof for signs of damage to or displacement of the individual layers of construction, perishable materials including mastic sealants and mortars, build-up of vegetation or debris, and rooftop installation mountings for confirmation that their attachment remains waterproof. These biannual inspections are a condition of the British Standard and of every major membrane manufacturer’s warranty. Vector carries out these inspections as part of our planned preventative maintenance and Complete Roof Assurance services.

Note 2 to Clause 8.2 states that electronic devices are available to detect leaks and heat loss. This is the British Standard’s recognition that sensor-based monitoring and electronic leak detection technologies — the core of Vector’s permanent leak detection service — are legitimate and recommended tools for flat roof maintenance and defect identification.

Standard: BS 6229:2018 — Flat roofs with continuously supported flexible waterproof coverings — Code of practice | Publisher: BSI

Joint Code of Practice — Escape of Water Prevention on Construction Sites

The Joint Code of Practice (JCoP) for the Prevention and Management of Escape of Water on Construction Sites was published in 2024 by RISCAuthority and the Construction Insurance Risk Engineers Group (CIREG), endorsed by the London Engineering Group (LEG) and the Chartered Institute of Plumbing and Heating Engineering (CIPHE).

This is the insurance industry’s collective technical position on water damage prevention during construction. Escape of water costs UK insurers approximately £1 billion per year, and a single event in a multi-tenanted high-rise can generate claims exceeding £30 million. The JCoP requires that water escape risks be handled with the same seriousness as fire hazards.

Key requirements include mandatory Water Systems Management Plans, automated shut-off valves, leak detection sensors on all water supply risers, and continuous monitoring of temporary water supplies. Compliance is rapidly becoming a condition of construction insurance cover on major projects — non-compliant contractors face higher premiums or exclusions.

Standard: Joint Code of Practice — Escape of Water Prevention and Management on Construction Sites (2024) | Publishers: FPA / RISCAuthority / CIREG

CLT and Mass Timber — Moisture Monitoring in Modern Construction

Cross-laminated timber (CLT) and mass timber construction is growing rapidly in the UK, but these structures are acutely vulnerable to moisture damage. Unlike concrete, which tolerates intermittent wetting, CLT panels can suffer irreversible structural degradation if moisture content exceeds critical thresholds — and the damage often progresses hidden behind finishes until it becomes a major structural concern.

Multiple standards now address this risk. BS 5250:2021 provides the framework for moisture management in buildings, including condensation risk analysis and the specification of monitoring systems. BS EN ISO 6781-1:2023 covers thermal performance assessment using infrared thermography — a key diagnostic tool for identifying moisture ingress pathways in timber-framed and CLT buildings.

For retrofit projects, PAS 2035:2023 requires monitoring and evaluation plans that explicitly include moisture assessment, referencing BS 40101:2022 for sensor specifications — continuous temperature and humidity monitoring at 30-minute intervals for a minimum of 12 months, with defined accuracy thresholds.

Standards: BS 5250:2021, BS EN ISO 6781-1:2023, PAS 2035:2023, BS 40101:2022 | Publisher: BSI

CIRIA C817 — Blue Roofs: Design, Implementation and Monitoring

CIRIA C817 is the definitive UK guidance on blue roof design and implementation — the practice of using flat roof structures for stormwater attenuation. Vector’s Ben Hickman was a Key Technical Author of this publication, which represents the current state of the art in blue roof engineering.

Blue roofs introduce a deliberate design condition where water is retained on the roof membrane for extended periods. This creates a fundamentally different risk profile from conventional flat roofs — the waterproofing membrane must perform not just as a weather barrier but as a permanent containment layer. Any defect in the membrane becomes a pathway for water ingress into the building structure below.

C817 addresses this by emphasising the importance of waterproofing integrity testing, ongoing monitoring during the operational life of the blue roof, and the specification of leak detection systems that can identify and locate membrane defects beneath the attenuation layers. This is directly relevant to Vector’s buried leak location service, which uses electronic field testing to pinpoint defects through complex build-ups without destructive investigation.

Publication: CIRIA C817 — Blue Roofs: A Guide to Design, Implementation and Maintenance (2021) | Publisher: CIRIA

LRWA GN18:2025 — Electronic Integrity Testing of Waterproofing Membranes

LRWA Guidance Note 18 (2025) provides the Liquid Roofing and Waterproofing Association’s technical guidance on electronic integrity testing (EIT) of waterproofing membranes. EIT is a non-destructive testing method that uses low-voltage or high-voltage electrical pulses to detect breaches, pinholes and defects in roofing and waterproofing membranes — without any need to remove overburden or finishes.

This guidance note is directly relevant to Vector’s buried leak location service. When a roof or podium deck is leaking but the membrane is concealed beneath insulation, ballast, paving or green roof systems, traditional investigation requires expensive and disruptive removal of these layers. Electronic field testing offers a precise alternative — locating the defect to within centimetres, so remedial work can be targeted rather than wholesale.

Vector uses this technology routinely on complex flat roofs, podium decks and buried waterproofing systems where the cost and programme impact of exploratory strip-back would be disproportionate to the repair.

Publication: LRWA GN18:2025 — Electronic Integrity Testing | Publisher: Liquid Roofing and Waterproofing Association

Need technical guidance on your project?

Whether you’re specifying leak detection for a complex basement, investigating a roof leak on a CLT building, or need to understand how sensor monitoring fits into your waterproofing design — we can help.