Drone-Generated Thermal Maps are a Game Changer for Roof Inspections

July 18, 2017

Roof inspections are dangerous and time-consuming. Inspectors must scale tall buildings to check for the smallest issues, such as cracks, leaks and weak spots that can compromise a building’s infrastructure. What’s worse, many inspections must be completed at night in order to spot temperature anomalies that signal the presence of a leak. Drones are changing the game when it comes to roof inspections, making them safer and more efficient for construction companies around the world. Here’s the story of one architecture and construction firm that transformed their inspection process through the use of drones and thermal imagery.


Founded in 1912, The Beck Group is a Dallas-based commercial architecture and construction company that specializes in construction, design and architecture for many of the largest commercial facilities in the US and Mexico. Some of their notable clients include the Tampa International Airport, Salvador Dali Museum and Duke University. In 2014, the firm began incorporating drones into its workflows, using aerial maps and models to improve site documentation, collaboration and design.

Grant Hagen is a virtual design and construction manager at The Beck Group
Grant Hagen is a virtual design and construction manager at The Beck Group

Grant Hagen is a virtual design and construction manager at The Beck Group. As he puts it, his team knew it was time to start using drones, “when practicality met technology.”

Grant led the charge to integrate thermal mapping into The Beck Group’s inspection workflow, and so far he’s seen success using DroneDeploy to produce high-resolution thermal maps and 3D models. We recently spoke to him about how drones and drone mapping software improved safety and increased efficiency during a thermal roof inspection of a building on the UT Dallas campus.

University Seeks Thermal Inspection to Document Structural Issues

The Naveen Jindal School of Management at UT Dallas, the largest of the university’s seven schools, is comprised of two main buildings. The newer of the two structures was built by The Beck Group. The older structure, built by a different firm, has started to experience a variety of exterior skin issues, including a roof in dire need of repair.

In 2016, UT Dallas Facilities Management decided to apply for internal funding to cover the cost of repairs. This process included submitting a strategic proposal to highlight the building’s exterior issues and outline a plan for improvement. To document the extent of the roof damage, the university initially hired an outside company to perform a thermal inspection of the building.

The Naveen Jindal School of Management at UT Dallas
The Naveen Jindal School of Management at UT Dallas

Thermal cameras are a powerful tool for conducting roof inspections. Wet areas on a roof retain heat longer than dry areas. After the sun goes down and a roof begins to cool, thermal imagery detects these temperature differences and helps inspectors pinpoint areas of concern that warrant a closer look.

Typically, a thermal roof scan is done either on foot or by helicopter. In this case, UT Dallas Facilities Management hired a company to capture thermal imagery via helicopter. The university has used this method of aerial thermal capture in the past. In this case, they hoped that the imagery gathered for the management building would not only provide important data for the inspection process, but also be included in the improvement plan documentation as a way to illustrate the building’s exterior issues.

But as with any tool, thermal cameras are only as effective as the methods that are used to administer them. As the university soon learned, obtaining thermal imagery via manned aircraft has its drawbacks.

Red and green areas in the picture denote the areas of the roof and facade that needed to be inspected using thermal imagery.
Red and green areas in the picture denote the areas of the roof and facade that needed to be inspected using thermal imagery.

Manned Aircraft Fails to Generate High-Resolution Thermal Imagery

One of the biggest drawbacks to gathering thermal imagery via manned aircraft is the quality of data that can be gathered. Out of necessity, the helicopter that flew over the UT Dallas building did so at between 2,000 and 2,500 feet. Images taken from this height are relatively low resolution, especially compared to images taken from a drone at a few hundred feet. And when it comes to thermal temperature measurement, low resolution translates into low accuracy.

The Facilities Management team also worried that the imagery they acquired via helicopter would do little to bolster their funding application. They were left with a series of individual images, each representing a single section of roof. But it’s difficult to contextualize a group of individual thermal images, especially when you are trying to get a sense of the integrity of the roof as a whole.

“They only got about 20% of what they asked for,” Grant says of the thermal imagery the school obtained via helicopter. So when The Beck Group shared with them the possibility of using a drone instead, they took notice.

Thermal 2D map of main UT Dallas Naveen Jindal School of Management building. The map helped validate the presence of exterior issues. Explore the map
Thermal 2D map of main UT Dallas Naveen Jindal School of Management building. The map helped validate the presence of exterior issues.Explore the map

Drones Save Valuable Time, Making Inspectors More Effective

Eventually, UT Dallas Facilities Management hired The Beck Group to complete a new thermal inspection of the roof, this time using a drone and aerial mapping software. Grant and his team gathered the images with a DJI Inspire 1 equipped with a Zenmuse XT 640 and a 13mm lens. They flew the 3–4 story building at a height ranging between 180–200 feet and gathered a total of 90 images manually.

Because The Beck Group had only just begun to integrate drone-based thermal imaging into their workflows at the time they did this project, they decided to process the Radiometric JPGs through multiple aerial mapping software programs. Grant was most impressed with the accuracy of the map he generated in DroneDeploy.

We ran the thermal imaging data with almost every software,” says Grant. “DroneDeploy was the only one that worked. And it was easy

Not only was the quality of the thermal drone map a vast improvement over helicopter imagery, but the entire process proved to Grant and his team what they had suspected for some time: drone-generated thermal maps are a powerful inspection tool.

By remotely identifying problem areas, in real-time and in a matter of minutes, inspectors can focus their work and limit on-the-roof time to only those areas of concern. “Rather than searching for a needle in a haystack,” says Grant, “you have a map to tell you right where to look.” This ultimately reduces inspection time, in some cases by as much four hours.

Grant also points out the quality of data that can be acquired with drone mapping. With a thermal drone map, his team is able to dig more deeply into temperature anomalies, ultimately providing a more thorough inspection.

The work input to value output with drone-based thermal imagery is game changing. It’s unlike anything else in construction technology right now.

In the case of UT Dallas, the 3D thermal models that are automatically created as part of DroneDeploy’s stitching process were an added bonus. These models gave the university yet another valuable tool by which to point out the building’s exterior issues. Ultimately, they leveraged this entire package of thermal data in their funding application and were granted the money they needed to repair the roof.

Grant Hagen flying on a jobsite with the DJI Inspire 1
Grant Hagen flying on a jobsite with the DJI Inspire 1

Drone Mapping Improves Safety of Commercial Roof Inspections

As any site manager knows all too well, slips, trips and falls are the biggest risk facing workers today. In fact, falls are the leading cause of death on industrial jobsites and were responsible for eight hundred OSHA-reported fatalities in 2015. By allowing inspectors to perform remote inspections with real-time information, drone mapping reduces the amount of time workers spend in dangerous areas. If an inspector can reduce the time spent on a roof by 3–4 hours, that’s 3–4 hours he is on the ground and out of harm’s way.

Learn more about how drones are increasing jobsite safety on industrial worksites.

When it comes to thermal roof inspections, the possibility of gathering data remotely is especially enticing. Most thermal inspections must be done at night, because this is the time when a building has begun to cool and temperature anomalies are the most evident.

Being on a roof at any time can be dangerous. But this is especially true at night. Any time you can limit putting your staff in a dangerous situation, it’s a win.

Looking Ahead to the Future of Drones and Roof Inspection

The roof inspection at UT Dallas was one of the first times The Beck Group used drones for thermal imaging. After the success of the project, they have continued integrating thermal maps into their inspections workflow.

Grant sees great possibilities. “We should be doing this more often,” says Grant. Gathering thermal images with a helicopter is expensive. But with drones, he notes that they could inspect more regularly for little added cost. “We could perform proactive inspections on demand, without limitations.”

“Believe the hype that you are hearing,” Grant says to colleagues thinking of taking the plunge into drone technology. “Don’t turn a blind eye to it; the value is there. If you don’t get involved soon, you’ll have a hard time keeping up. Drones are going to change the industry — it’s already happening.”

Where to Learn More

Interested in hearing more about how The Beck Group transformed its roof inspection workflow using DroneDeploy? Register for our upcoming webinar Improving Commercial Inspections and Jobsite Safety with Drones.

From roofs, to elevated cell towers, to landfills, drones make jobsite safer. Read more about the many ways drones improve safety on industrial sites.

DroneDeploy recently launched two news tools specifically for the construction industry. Be sure to check them out:

If you’re interested in learning more about making accurate maps and 3D models, read our latest resources:

Learn more about the many ways to get started with drones in construction:

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