Answering Your Questions About Roofing

Diagnosing Flat Roof Leaks Using Infrared Technology

by Donald Evans

Flat roofs are a common feature of institutional, commercial, and industrial buildings across the country. They are valued for their ease of access, as well as for allowing large HVAC units to be housed on top of the building. Yet a flat roof can turn into a nightmare should it happen to develop a difficult to locate leak. Fortunately, finding pesky flat roof leaks is no longer as hard as it used to be, thanks to the use of infrared technology. This article will explain how infrared (IR) technology can help you can locate the source of a leak on your flat roof.

The Problem

Flat roof leaks represent a huge problem--and not just for the structural elements of your building, but also for your overall energy efficiency. You see, when water finds its way beneath the protective coating on a flat roof, it soon begins to saturate the underlying layer of insulation. Wet insulation has a much lower insulating value than dry insulation, meaning that you will soon find your energy consumption rising.

Thermal Capacity Differences

Infrared technology allows for a unique and highly effective method of detecting roof leaks. It utilizes temperature differentials in the surface of the roof to locate leak positions. Such temperature differentials arise as the result of the water-saturated portions of insulation. You see, these areas will absorb the sun's rays much more slowly than the rest of the roof. That's because water's thermal capacity is much greater than the dry insulation surrounding it.

This thermal capacity has an interesting effect once nighttime rolls around and your roof begins to cool off. The portions of the roof containing dry insulation will quickly release their heat. But the water saturated areas, which had absorbed heat much more slowly, will also release it much more slowly. In other words, there will be so-called "hot spots" in the places where water has leaked beneath the surface of the roof.

IR Leak Detection

These hot spots are the key to infrared leak detection. An HVAC technician equipped with an infrared camera will head up to your roof on the night following a hot sunny day. The camera will allow them to see a picture of the thermal gradients across your roof. Water-saturated areas will appear as a different color--usually orange or yellow--from the rest of the roof, which will be more of a blue or purple shade.

The technician will then carefully mark off the boundaries of this temperature gradient using a can of spray paint. Using this information, your roofing company will know exactly what portions of the roof your leak is affecting--and thus which portions will require their attention and repair efforts.