Thermal Drone Roof Inspection

A thermal drone roof inspection uses a radiometric thermal camera to inspect a roof system. A thermal or infrared camera is able to “see” the relative differences in the way a roof system or roofing material gives off heat.

In warmer seasons a compromised section of a roof may become saturated with water. Since water absorbs and emits heat more slowly as compared to the adjacent roof surface, a wet roof surface area will cool more slowly during the evening. It is this difference in relative cooling that allows us to see hotspots and areas that may be potentially saturated with water.

In cooler seasons, when there is a large temperature difference between the inside of a building and the outside (ASTM1153, 9.3), it’s possible to detect potential anomalies in a roof system without the presence of water. Compromised roof structures may show higher relative heat loss as compared to adjacent roof areas.

Generally, infrared drone inspection methods use the relative difference in heat loss of roof systems and/or roof material to detect potential problems in roof systems.

Using thermal imaging to conduct roof inspections is nothing new. In 1990, the ASTM published C1153, Standard Practice for Locating Wet Insulation Using Infrared Imaging, and is still in use today with very few changes.

We use drones to conduct thermal inspections of roofs for several reasons.

Thermal drone inspections help detect leaks and defects in roofs. Detecting leaks and potential defects can catch problems before they become costly repairs.

Drones used for infrared inspections can also be to verify the proper installation of roof systems. Drone-based roof thermography combined with expert construction review can help verify contract conditions have been met. 

A thermal drone inspection offers speed and efficiency as well as a unique perspective. Drones can quickly survey very large roof surfaces. Speed and efficiency directly translate to cost savings for a given inspection. 

Thermal inspections by drone keep people off of roofs and reduce the risk of injuries related to falls. The cost of a roof inspection by drone will pay for itself 100’s of times over when compared to a catastrophic and potentially libellous workplace accident.

Infrared inspections using a drone can also be combined with energy loss assessments for a given building envelope and help a company reduce energy costs and lower carbon emissions  

First and foremost Recon Aerial conducts all aerial drone flight operations in full compliance with the RPAS regulations and in conformance with our internal procedures for safe, efficient drone operations.

With limitations, Recon Aerial conducts qualitative thermal roof inspections by drone in accordance with best practices as described by aerial requirements of ASTM C1153. 

Recon Aerial first conducts a daytime visual inspection. During the visual roof inspection, we capture both RGB and thermal images. As per ASTM1153, 11.2.4., within 2 days Recon Aerial conducts a thermal roof inspection. Once the inspection is complete the data is compiled and reviewed. Within 14 days, often sooner, a report is generated detailing findings that may be significant, and that may require further investigation. The client is provided with both the raw image data and report(s). Recon Aerial can also recommend engineering support to help further quantify potential issues.

In the example below thermal images were taken by drone in winter when there was a high difference between the exterior temperature and the interior temperature of the building. In this case, the RGB image shows a black patch on the roof where the pea stone roofing material has been disturbed/removed.

A brief analysis of the radiometric jpg images of this roof tells us that the max temperature of SQ1 was on average 3.5C greater than similar-sized adjacent areas on the same roof. This area of concern appears to be releasing heat at a significantly higher rate as compared to the same material on the adjacent roof areas. 

The integrity of the roof area appears to be compromised and may indicate a potential point of water ingress if left unrepaired. At the very least it is emitting energy needlessly into the environment adding unnecessary cost to the management of this building.

Using a drone for infrared roof inspections demonstrates that thermal imaging for roof leak detection holds great value for property owners, property managers, and anyone having a vested interest in reducing building maintenance and management costs.  Ensuring the proper function of a roof system saves energy, and prolongs the life span of a roof.