Electronic Leak Detection and Prevention System – Controlit ELP EDP

Conductive substrate — Controlit GS

Water infiltration is one of the most frequent and costly problems in the construction industry and can have serious consequences.

The waterproofing business today is largely based on trust: “We have 30 years of experience in this field — you need to trust us, choose us even if we are more expensive.”

The client accepts the higher price and better materials because they want peace of mind after the roof or building has been handed over. Waterproofing contractors work with people — some highly experienced, others less so due to labor market fluctuations — and mistakes can happen.

But let us assume the waterproofing team does a perfect job, flood-tests the roof before handover, finds no issues, and leaves the site. Then other teams arrive to install mechanical systems and, through carelessness, puncture the once-perfect waterproofing membrane in dozens of places.

The addition of a conductive support layer directly beneath the waterproofing membrane layer(s), using the Controlit system, enables precise and non-destructive testing of the waterproofing membrane’s integrity. It allows for electronic leak prevention (ELP), ensuring the roof remains testable during installation, handover, and post-installation maintenance throughout the entire lifespan of the building.

What this technology consists of

A conductive fiberglass substrate with a stainless-steel nano-coating, designed for both bituminous and synthetic waterproofing systems (PVC, TPO, etc.). It allows repeated integrity testing using both high-voltage and low-voltage methods, in accordance with ASTM standards (D7877 and D8231).

Controlit support layers are installed directly beneath the waterproofing membrane layer(s) to create a uniformly conductive layer across the entire waterproofed surface, together with contact points: stainless steel connection contacts sealed with membrane-specific clamps (bitumen or PVC/TPO), enabling proper electrical connection for ELD.

This makes electronic leak detection (ELD) possible — but more importantly, it enables electronic leak prevention (ELP).

This is not just about detecting problems after serious damage has occurred, but about preventing them from the handover stage onward, followed by repeated testing at predefined intervals or after any intervention carried out on the roof.

Technical data

ODU Green Roof is the official Controlit representative in Romania and provides full support for the installation of this high-performance system.

✅ ELD / ELP – Electronic Leak Detection / Prevention

• A non-destructive method that uses low- or high-voltage electrical current.
• The waterproofing membrane acts as an electrical insulator.
• Any perforation or defect creates a current leakage point → the defect is located with centimeter-level accuracy (high-voltage testing is performed on a dry roof, while low-voltage testing requires residual moisture).
• Can be applied before installing the upper layers (drainage, substrate, paving), or even after their installation by wetting them and testing using the low-voltage method.
• Ideal:
  • before and after green roof installation
  • before and after paving installation
  • before and after project handover
• Allows fast (1–5 hours) and cost-effective repairs, avoiding the uncertainty of flood testing, because we not only know that there are holes in the waterproofing, but exactly where they are — even if they are not visible to the naked eye.
• Highly precise defect localization (±1–5 cm), capable of detecting micro-perforations, differentiating between multiple defects, with quantifiable results.
• No water required
• No mechanical stress
• No risk to the structure or finishes

❌ Flood testing

• With flood testing, you only know that a problem exists, not where it is. Once water infiltrates beneath the waterproofing membrane, it can migrate tens of meters from the point of entry and manifest elsewhere, such as through the ceiling.
• Defect localization is not possible, micro-perforations cannot be detected, multiple defects cannot be distinguished, and results are not quantifiable.
• Requires filling the roof with water (typically for 24–72 hours, meaning testing can take days), which on large roofs may involve hundreds or thousands of cubic meters of water.
• Checks whether leaks appear on the lower level (ceiling side).
• A passive method based on visual observation and time.
• May load the structure with hundreds of additional kg/m², sometimes not permitted by structural engineers.
• If waterproofing defects exist, there is a high risk of infiltration into:
  • thermal insulation
  • concrete structure
  • interior finishes
• If leaks occur, there is a risk of water saturation that can compromise thermal insulation and damage interior finishes (gypsum board, paint).
• Difficult to apply on sloped terraces, large roofs, or sensitive structures. Essentially useless after upper layers are installed, because if leaks are detected, these layers must be removed, resulting in enormous costs (consider an intensive green roof with 400–500 m³ of substrate and trees 8–10 m tall).

Technical conclusion

✅ ELD / ELP:

• a modern, safe method with precise defect localization
• an industry standard in serious projects
• recommended for public buildings, hospitals, shopping centers

❌ Flood testing:

• an outdated, rudimentary method (it tells us there is a major problem but not where — like looking for a needle in a haystack)
• high risk, limited information
• acceptable only in simple, temporary situations

In practice, electronic testing not only replaces flood testing, but renders it obsolete in most contemporary projects. Why take such a risk just to avoid an investment of approximately EUR 15–17 + VAT per m²?

An investment that prevents incomparably higher costs over the coming decades — costs that occur with significant delay, involve slow intervention, and lack precision.

Imagine discovering a serious water infiltration on the ceiling. You cannot find any significant hole in the waterproofing membrane, only a few possible minor defects. You repair them, yet the infiltration persists. Eventually, you decide to redo the waterproofing over an area of 200–300 m² in zones where the roof slope could channel water toward the observed leakage area. This comes at a cost of EUR 4,000–9,000, whereas ELD / ELP could have precisely indicated the problematic areas, allowing the damaged waterproofing to be repaired with just 2–3 m² of material.

After this experience, you realize: with that money, you could have installed an electronic leak prevention system over the entire roof.

What can you do in such situations?

You grope in uncertainty. You hope the damage will not be severe, that water will not reach expensive, high-precision equipment in the production hall — because if a single machine fails, the entire production line may have to stop, orders are delayed, and clients are lost (every business has sensitive points that can be disrupted by an infiltration that could have been prevented). These losses far exceed the cost of an electronic leak prevention system.

Isn’t it better to be able to quickly check the roof’s watertightness after every intervention and repair any defects immediately?

Controlit GS technical data – bituminous membranes:

Comparison of real costs between the two methods: ELP vs. flood testing

Costs are indicative and may vary depending on roof size, access, equipment, contractors, region, and other factors.

✅ ELP costs

Starting from approximately EUR 1.50 – 4.00 /m², depending on roof complexity, number of penetrations, and installed systems. This cost includes consultancy, fixed monitoring equipment, rapid identification of defective areas, reporting, and precise localization. Continuous or periodic testing is possible. Major advantage: you find the exact problem before it causes damage and can fix it quickly!

❌ Flood testing costs

Starting from approximately EUR 0.50 – 1.50 /m², but additional preparation costs apply: temporary edge waterproofing, protection of interior finishes = EUR 200–1,000, water removal and drying = EUR 100–500, potential damage or deterioration of finishes, and lost operational costs if the area must be closed (difficult to quantify, but potentially enormous in case of failures). In practice, the real total often reaches EUR 2.00 – 5.50 /m² or more, depending on complexity and damage caused by the flooding itself.

For your safety and the protection of your investment, we recommend including the following wording in the technical specifications:

Bituminous waterproofing works

After application of the primer, a Controlit GS High Voltage leak detection system, or an approved equivalent designed for bituminous membranes, shall be installed.

Characteristics: Conductive substrate — Controlit GS or approved equivalent.

A conductive fiberglass substrate with stainless steel nano-coating, designed for both bituminous and synthetic waterproofing systems. It allows repeated integrity testing using high-voltage and low-voltage methods, in accordance with ASTM standards (D7877 and D8231).

Technical properties:

• Electrical resistance: < 1000 Ω/sq
• Fire classification: A2-s1,d0 (EN 13501-1)
• Weight: 165 ± 10 g/m²
• Roll size: 1.65 m × 50 m

Contact points: Stainless steel connection contacts, sealed with membrane-specific collars (bitumen or PVC/TPO), ensuring proper electrical connection for ELD.

Purpose: Enables precise and non-destructive testing of the waterproofing membrane integrity. Allows permanent electronic leak prevention (ELP), ensuring that the roof remains testable during installation, handover, and throughout its service life.

During execution of the terrace waterproofing works, the membrane manufacturer’s installation and application instructions shall be strictly observed.

Waterproofing testing

Before final acceptance of the works, the contractor is obliged to subject the waterproofing system to a watertightness test using an electronic leak detection method (ELD – Electronic Leak Detection). Flood testing may only be accepted during unfinished construction stages. For final acceptance, a safe method without risk to the structure is required; therefore, the ELD method is mandatory.

Testing shall be carried out by a specialized company independent of the contractor, using dedicated equipment, in accordance with recognized international practices (ASTM D7877 / ASTM D8265 or equivalent).

The test results shall be documented in a written report containing:

• the tested surface area,
• the method used,
• precise localization of any detected defects,
• a conclusion regarding the waterproofing compliance.

Acceptance of the waterproofing works may only take place after all identified non-conformities have been remedied and watertightness has been confirmed through retesting. The costs associated with ELD testing are included in the contract price and shall be borne by the contractor.