infrared roof inspection

Roof inspection can reduce your annual repair budget by evaluating your roof system and identifying water intrusions prior to major roof system damage caused by water infiltration. Infrared moisture survey is a vital diagnostic procedure that is used to inspect a roof’s condition. Infrared thermography allows a certified technician to locate moisture laden areas during night-time scanning. The entire roof moisture survey takes place without penetrating the roof surface unless core sampling is required.

Flat roof membranes are the waterproof barriers between the outside elements and the interior of a building. The roofing assembly will expand and contract with the temperature swings, resist high winds, the effects of solar radiation and withstand foot traffic. It is easy to see why flat roofs deteriorate and leak.

Normally there is no water within a flat roof assembly. When a leak develops, water enters the assembly and depending on the type of insulation, it is either absorbed by the insulation or runs between the joints of the nonabsorbent insulation. If water enters the roof assembly it will most likely stay there for the life of the roof.


How does a thermal camera detect wet insulation?

An infrared camera can see and measure heat differences in building materials such as roofs. Wet or moist areas usually have a different temperature reading than dry areas due to evaporative cooling, increased conductance or thermal capacitance.  Accordingly, the wet areas will appear relatively darker or lighter than the dry areas on an infrared picture, enabling the technician to locate them.  An IR camera will, in the hands of an experienced technician quickly and non-destructively identify the location and approximate size of moisture damaged areas.

Thermal images are sometimes deceiving because moist areas can equalize in temperature depending on the time of day or depending on the length of time since moisture first occurred.  It takes experience and knowledge to know when other tools, like moisture meters, may be necessary. In general, infrared inspections are best performed at night after a sunny day on a dry roof surface. Any wet insulation under the roof membrane will have a different heat signature and will cool at a different rate after a sunny day versus the dry parts of the roof. An IR camera will pick up this temperature difference and display it in different shades of color. Wet areas often manifest themselves as warmer areas and they are commonly found in two forms; linear or puddle-like shapes. The linear shapes many times follow low areas, drainage routes, roof edges and seams. Puddle-like round or oblong shapes often form around roof penetrations such as mechanical equipment, standpipes, vents and drains.


The annual cost of an infrared roof inspection is far less than the impact of substantial water intrusion. Every building should have a roof management plan with an annual infrared roof inspection. This will not only identify active roof leaks but will establish a baseline for annual testing. No matter how brilliant the infrared imagery, this is still not proof-positive of wetness or in any way quantitative with respect to the roof moisture content within the substrate. This is by definition non-destructive testing, so verification must be performed by core sampling and measurement of the moisture content using a moisture probe.

To learn more about our Roof Asset Management Program, please contact SMC Group at (416) 731-7737 for more information.