Inspecting Shaded Building Elevations
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Inspecting Shaded Building Elevations
Tip written by: Infraspection Institute
Infrared inspections of building exteriors often rely on solar loading to create temperature differentials necessary to detect damage or defects. A common challenge for thermographers is inspecting building elevations that do not receive direct sunlight.
Infrared imaging is a proven technique for testing building sidewalls. Inspecting buildings during evening hours following a sunny day can reveal the presence of structural details, missing or damaged insulation, or latent moisture. These conditions are detectable due to changes in the thermal capacitance or conductance of the walls.
When using solar energy to drive an infrared inspection of building sidewalls, it is normal for a building to heat unevenly. Typically, east elevations receive the least direct sunlight, while the south and west elevations receive the most. For many northern latitudes, north elevations do not receive direct sunlight.
Fortunately, it is not necessary to receive direct sunlight in order to drive an infrared inspection. Provided that the building is not in close proximity to other structures or heavily shaded areas, it will receive indirect heating from nearby objects such as the ground. For elevations that are heated indirectly, it is important to note that they will exhibit weaker thermal patterns when compared to other exposures that receive direct sunlight.
When using solar loading to drive an infrared inspection, keep the following in mind:
- Choose an evening when weather conditions are optimal – sunny day followed by a cool clear evening with no wind
- Begin infrared inspection on the North elevation and continue in a clockwise fashion around the exterior of the building
- Depending upon wall construction, type of defect, and local weather conditions, it may be necessary to begin prior to sunset
Lastly, be aware that thermal patterns associated with defects may only appear for a short period of time on the North and East elevations. All thermal anomalies should be investigated for cause and appropriate action taken.
Infrared inspection of building envelopes is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
