The traditional method of locating sources of leaks in roofs is by physical visual examination to find cracks, holes, or cleavages in the roofing material. Normally parch marks left on the surface roofing material after the water has evaporated can be followed to trace to the point of entry of the water. The physical examination involves entering into the ceiling and trying to find the source of the leak by visual examination with the aid of a flashlight.

Sometimes the ceiling would be broken down to allow accessibility, leading to demolition and repair costs. The occupants of the building are also inconvenienced when the furniture and equipment are moved to allow accessibility. By locating leaks using infrared thermography, all the above problems are avoided. In addition, the method is fast and reliable.

Infrared thermography involves taking photographs(called thermograms) of the leak area using an infrared camera. An analysis of the thermograms will reveal the sources of the leaks. Only a good infrared camera, a ladder, and a few trained personnel are required.

Thermography is the use of infrared imaging and measurement to detect and measure thermal energy emitted from an object. Thermal or infrared energy is the light that is not visible because its wavelength is too long to be detected by the human eye. It is part of the electromagnetic spectrum that we perceive as heat. Unlike visible light, any object with a temperature above absolute zero emits heat. Even very cold objects such ice cubes, emit infrared light. The higher the temperature of the object the greater the infrared radiation emitted. Infrared cameras allow us to see what our eyes cannot see.

The infrared camera takes advantage of the unique thermal properties of water to show where it is present. The camera is able to detect the presence of water both on the surface and within the building material being examined. When water evaporates on the surface of the material it cools and maintains a lower temperature than other points on the material where there is no moisture. A photo taken by the infrared camera will show different colours for different temperatures. Pictures are taken on the suspect areas of the roof and the ceiling prior, during and after water testing. Because the infrared rays are able to measure infrared radiation of materials, the thermal differences will indicate the presence of water on or within building materials on the roof, ceiling or walls.

A thermography moisture survey report consists of a written description of the results of the roof moisture survey, the calibrated tool used to identify moisture content, method used to perform the survey and a detailed colour survey graph of the roof indicating the findings. The picture from the camera only shows relative moisture content. The calibrated tool will give the exact moisture content. An infrared camera is the best solution for locating roof leak sources because it is simple, safe, reliable, accurate, fast and cost effective.

Infrared thermography cameras produce images of invisible infrared or heat radiation and provide non-contact temperature measurement capabilities. Nearly everything gets hot before it fails making infrared cameras extremely cost effective, valuable diagnostic tools in many diverse applications. It is also very effective because it detects even moisture retained in the building material. It is easy to use as the process requires few personnel. Roof moisture surveys are reliable non-invasive tools to help pinpoint the scope of moisture infiltration. This survey used in conjunction with the forensic roof analysis is a dependable tool used to initiate course of action for either maintenance and/or replacement of some roofing materials. It is also used during manufacture of roofing materials to test for defects.

Such a survey is very useful to one intending to purchase a house because it will reveal the soundness of the roof before the purchase is made. Its non-invasive and simple properties make it highly cost effective. It is non-destructive because the ceiling, parts of the roof and the walls do not have to be extensively damaged to allow access and also saves reconstruction costs. As mentioned above a lot of savings on repair costs is avoided if the leaks are identified before purchase. There will be no inconvenience caused by moving furniture and equipment. The survey can be completed very fast making it suitable even during the rainy season. The speed of using infrared and the larger areas covered rapidly by the infrared camera can save time and money by providing a faster, more efficient and more reliable survey. This vital tool will guide the corrective action to be recommended for necessary repair. An infrared camera can detect moisture located in areas otherwise difficult to reach such as interior of walls under the right conditions. The temperature difference created by the presence of moisture on the inside surface of, take for instance, a wall will appear differently, on an infrared photograph, than the surrounding area. Using infrared camera for leak detection avoids ceiling stains, and water condensation. Repairs will be made early before a bigger problem develops.

by John Oduor Kombo

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