Leak detection

The roof leak detection is based on sophisticated measurement methods, which examine the package of roof layers for dampness in a completely non-destructive manner.


Professional and non-destructive leak detection and moisture mapping with the certified SLD measurement methods avoid cost-intensive restoration work and prolong the service life of your flat roofs. Prior to testing, the customer can be shown an initial projection of the test accuracy with the help of a unique grading method for flat roofs (RTRS). All leaks and potential weak points are traced with pinpoint accuracy, documented in a detailed test and measurement report, and presented as a visual work plan.


Precision and high-tech method

All leaks and places to be dried or restored are localised by the impulse current method with pinpoint accuracy. Depending on the task, the SLD technicians use three innovative methods for detection. All damaged areas are also documented in a detailed test and measurement report and presented in technical drawings and in photographs as a visual work plan. The cost-saving repair of the damaged areas can be initiated immediately with pinpoint accuracy.

Moisture Mapping

Moisture mapping of the roof layers using the impedance method

1. LV SLD

Low Voltage – Sensor Leak Detection with the wet detection method.

2. HV SLD

High Voltage – Sensor Leak Detection with the dry detection method.

3. HVS SLD

High Voltage – Sensor Leak Detection with spot and seam testing.

Video Leak detection


Frequently asked questions

The majority of the roof surfaces can be properly checked using the HV-SLD (High Voltage – Sensor Leak Detection) and LV-SLD (Low Voltage – Sensor Leak Detection) methods with pinpoint accuracy. For other roof surfaces, additional techniques and methods may need to be combined to achieve the best result.

All customers of the SLD Group also receive a guide for their quote: ROOF TEST RATING SYSTEM, referred to in short as RTRS®. The RTRS guide gives the customer a forecast in percentage points as an extension to the test result. Each roof surface is different in nature and condition and therefore requires an individual assessment in advance by SLD's qualified partners and experts. This service is always free of charge for our customers.

The duration of work depends on many factors such as the type of roof (with/without an extra load), the cleanliness of the roof surfaces, the number of superstructures, the weather conditions, the ascent to the roof surfaces, the type of roof sealing and many other soft factors. Depending on the situation on site and the current weather conditions, the SLD technician teams and the device pool can check and document large roof areas within a short space of time.

However, how long that takes has no influence on the price. All projects are offered and billed in m2 with a transparent fixed-price concept. In this respect, the time factor plays no decisive role for most customers.

SLD offers three different basic testing methods:

  • HV-SLD High Voltage – Sensor Leak Detection, also referred to as the dry testing method
  • LV-SLD Low Voltage - Sensor Leak Detection, also referred to as the impulse current method or wet testing method
  • IP-SLD Impedance - Sensor Leak Detection, also referred to as moisture mapping using impedance measurements

Each process has its own benefits under certain conditions. All methods can be combined with each other very well to achieve the best test results. Furthermore, these innovative measurement methods offer the best price/performance ratio. Our SLD technicians track all leaks and potential weak points with pinpoint accuracy. The damaged areas are also documented in a detailed test and measurement report and presented in drawings and in photographs as a visual work plan. On this basis, the specialist company can initiate the cost-saving repair of the damaged areas immediately.

We would be delighted to organise and manage the repair and restoration measures for you through our qualified roofing partners. We cooperate with leading roofing companies throughout Europe, who place emphasis on quality and sustainability in line with the SLD philosophy, without disregarding the economic factor. We offer you the entire portfolio of modern roof management from a single source. Ask our roof specialists today for your free roof check, RTRS® (Roof Test Rating System)

We would be delighted to offer you further methods such as thermography, smoke and tracer gas methods, as well as the camera inspection of processes and connections if required.

Depending on the situation and needs of our customers, there are widely varied reasons to perform a check.

a) Examples of situations concerning integrity testing:

  • Quality-conscious roofing companies book the SLD service to have their work checked neutrally and professionally and can thus offer their customers an enormous added value in terms of safety and status quo information
  • The partners of the SLD Group prepare integrity testing for the impartial final acceptance report
  • Preventative, regular checking intervals for sensitive systems and production lines, as well as for public buildings and everywhere where values are to be protected
  • If changes are to be made to the condition of the intact roof surface. For example the installation of PV systems (test before and after), after installation or repair work, etc.
  • Due diligence assessments, real estate exposé, takeovers, or the purchase and sale of existing properties

b) Examples of situations concerning leak detection:

  • Damage has occurred and the roof surface has to be examined in a quick, inexpensive and non-destructive manner
  • Roof surfaces are already in need of restoration, but they must still undergo measures to prolong their service life. Here the SLD technology helps to perform selective repairs with a system
  • In the case of disputes and claims, our independent specialist documentation helps roofers, experts and lawyers to clarify the liability issue


Does your company always have a complete overview of the condition of the flat roof? Talk to our sales partner and simply request the free SLD QUICK-CHECK for a swift diagnosis of your flat roof.

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