IR Roof Scans

Roof thermographers follow national standards or guidelines such as the Infraspection Institute Standard for Infrared Inspection of Insulated Roofs or ASTM C1153-Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging as the standard of reference to performing Infrared roof scans.

The new International Energy Conservation Code (IECC) has insulation requirements that can dramatically increase the cost to replace a roof membrane on a commercial roof. If the roof is repaired instead of replaced, then these insulation requirements do not apply, so repairing that leaking roof has a significant cost savings factor built-in. Using Infrared Thermography can lead to finding energy-robbing roof leaks. This can save hundreds of thousands of dollars on a typical job. Let TIP help extend the life of your existing roof and save you money!

Roof Infrared Basics

During the day, the sun radiates solar energy onto the roof and into the roof substrate. Then at night, the roof radiates this heat back into outer space. This is called "radiational cooling" as the heat from the roof is radiated into the cooler upper atmosphere. Areas of the roof that are of a higher mass (wet) retain this heat longer than that of the lower mass (dry) areas. Infrared imagers can detect this subtle heat difference and "see" the warmer, higher mass areas, during the "window" of uneven heat dissipation.

Infrared thermography views objects such as roofs in the two different wavelength (short wave, at 3000 to 5000 nanometers and long wave at 8000 to 14000 nanometers). This is well above the visible light wavelengths of 400 to 700 nanometers. Lights and other relatively hot objects are very evident, but as a result of their heat, and not their light emissions.

Infrared (IR) imagery is often a gray scale picture whose scales (or shades of gray) represent the differences in temperature and emissivity of objects in the image. As a general rule, objects in the image that are lighter in color are warmer and darker objects are cooler.

The heat energy is displayed in the Infrared image using different color pallets to show where the warmer areas are because of the moisture under the roof membrane. These display colors can be in Gray Scale, using a pallet of varying gray colors, Ironbow, using white / Yellow and Oranges, or Rainbow High Contrast using the spectrum of rainbow colors to indicate where the moisture is located. Ofcourse you must have proper weather, wind, temperature and physical conditions to perform these scans.

Cool Roofs or Single-Ply Roofing Systems

Roof emittance is the characteristic of how effective the roof material will radiate the heat that is stored in it based on the materials used in the roof membrane. Although cool roof materials are rated to have a high emittance, building owners should remember that this value is an average emittance value considered in a laboratory under ideal conditions and at a vertical viewing angle.

During an infrared roof inspection, smooth-surfaced roofs can be quite reflective to a thermal imager due to the low viewing angle that is usually associated with inspections performed on foot from the roof surface. This condition is most severe on cloudless nights when atmospheric humidity levels are low.

The single-ply roof systems such as EPDM, TPO, PVC and reflective coatings operate at a lower temperature thermal sensitivity and the wave length of the imager becomes a more important factor when choosing an inspection firm to conduct these inspections.