Thermal Imagery to Detect Roof Fasteners
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Thermal Imagery to Detect Roof Fasteners
Tip written by: Infraspection Institute
Thermal imaging is a proven technique for detecting latent moisture within low-slope roofing systems. Under the right conditions, thermal imaging may also indicate the number and location of roof fasteners.
Mechanical fasteners are a critical component in flat roofs. Essentially large sheet metal screws that are installed through large steel or plastic plates, mechanical fasteners secure sheets of insulation to the roof deck. In order to help ensure roof system performance, it is critical that each insulation board is installed with a sufficient number of fasteners.
An insufficient number of roof fasteners may be the result of improper design or a contractor attempting to cut corners on material. When fastener quantity is in doubt, a thermal imager may be used to indicate the number and location of fasteners. Typically, fasteners and plates will show as relatively warm components against a cooler background when imaged post-sunset after a sunny day. In the image below, subsurface fasteners and steel plates show as regularly-spaced warm circles.
When attempting to detect thermal patterns associated with mechanical fasteners, keep the following in mind:
- Thermal imaging should begin at or shortly after sunset
- Imagery associated with fasteners may only appear for a short time
- Fasteners may not be detectable on low emittance or gravel-surfaced roofs
Infrared inspections of flat roofs are one of the many applications covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For course schedules or to obtain a copy of the Standard for Infrared Inspection of Insulated Roofs, visit Infraspection Institute online or call us at 609-239-4788.
