Best practice roof defect detection

Category: Detect & Inspect Property Defects


Roof Defect Detection

Roof surveying is rarely straightforward. Depending on the conditions, the size and shape of the building, the surveying work can be labour intensive and demands significant preparation in order to identify and address the potential dangers.

While experience and training are key, infrared thermography is now established as a game changing technology that’s enabling surveyors to carry out analysis quicker and more accurately than ever before. Used in conjunction with other innovative approaches, it’s revolutionising roof surveying in the three areas that matter most – cost, accuracy and speed.

Surveying with infrared

infrared roofLet’s consider the following picture. Captured in a matter of seconds, this roof image not only reveals the extent of the problem for the client (saturated insulation), but also the source; the white air conditioning unit towards the rear.

Crucially, this highly visual result was produced without the need for destructive and speculative testing on areas of a perfectly functioning roof and could be completed without disrupting the building’s occupants. By securely attaching the camera to a large pneumatic mast, the image is captured without any risk to the surveyor despite relatively limited access to the roof.

Because infrared has identified the abnormalities for the complete roof and reported them in a usable and easy-to-understand graphic for the client, the approach also allows a roadmap for refurbishment to be properly planned in the context of one holistic view of the building – logistically very challenging to obtain with traditional surveying practices.

They say a picture is worth a thousand words – and images like this are the proof.

Surveying without infrared

Now consider surveying the same roof without an infrared camera. Access is the surveyor’s first concern and it may well be the case that scaffolding would have to be erected, with much disruption to the building’s occupants.

While a surveyor’s opinion on where problems exist is likely to be informed, a degree of speculation always remains. For instance, core samples from any of the purple regions in the photo will be dry regardless of how close to the problem they are. Meanwhile, establishing the extent of the problem requires the further drilling of holes and more trial and error testing.

The whole process is time consuming, costly and fraught with potential errors, not to mention hugely problematic for the building’s occupants who may ultimately face disruption for no reason.
While this approach is troublesome for surveyors, it’s likely to be even more so for the property owners, who are keen for issues to be identified and addressed as quickly as possible. Presented with the two options, therefore, and the infrared choice is a no-brainer.

before and after roof

Electronic leak detection

By using electronic leak detection (ELD) technology in conjunction with thermal imaging, surveyors can identify the precise location of penetrations in roofing membranes using an electrically charged ‘brush’.

With a voltage of up to 40,000 volts and conductive bristles constructed with phosphor bronze, the brush alerts surveyors to the precise location of pinhole penetrations in roofing membranes.
Unlike infrared thermography, its aim is not to establish the extent of problems, instead focussing on identifying where the holes are actually located.

With one end of the brush earthed to the building, the surveyor brushes over the roof surface and is alerted to penetrations by a visible spark and audible tone from the equipment. This allows he/she to mark the exact location of a problem area.

Like infrared thermography, one of the big advantages of ELD is that it is completely non-destructive, meaning tests can be carried out with little or no disruption to a property’s everyday running.

For instance, a recent test on a school roof in Blackburn saw the survey carried out while the school remained fully operational. In that particular project, IRT was commissioned to assess the condition of the property’s 6,800m2 roof due to concerns over missing insulation and moisture underneath the waterproofing system.

roof planWhile the thermal image identified 1462m2 of damaged insulation, ELD revealed 59 penetrations in the existing waterproofing system within the thermal anomaly regions. In other words, the client was given clear evidence of the extent of the damage and the precise spots of problems areas – thanks to the complementary relationship of ELD and infrared thermography.

The fact that ELD assessments can also be carried out quickly is hugely beneficial, particularly when a suspected roof is shown not to be the cause of a problem after all. This happened to IRT not so very long ago with a domestic dwelling survey. While the property owner believed moisture ingress to stem from a leak from the flat roof above the property, our ELD assessment quickly established that there were no penetrations and that the roof, in fact, was in excellent condition. It was down to the thermal image, therefore, to show the source of ingress to be porous brickwork on the walls, which was found to show anomalies in the same area both internally and externally.

While assessment of the roof using more traditional surveying techniques would have been time-consuming, hugely destructive and ultimately fruitless, the non-destructive and speedy nature of ELD ensured it was given the all clear without any inconvenience to anyone in the surrounding area.


IRT’s patented Envision software enables automatic energy quantification of images to recognised government standards. It extracts radiometric data from each thermal image and combined with an extensive range of metadata uses this to produce a truly unique report that quantifies energy loss in monetary terms.

That means surveyors can see precisely where and how much energy a roof is leaking and duly prioritise refurbishment programs accordingly.

Unlike the ‘hit and hope’ approach of the past, a combination of infrared thermography and Envision empowers surveyors to provide clients with visual evidence of issues and accurate ROI information – all from completely non-destructive tests.

If you are interested in more information then please do not hesitate to contact us.