If you were to ask a roomful of home inspectors if they have had any close calls on a rooftop, I bet most would raise their hands. Personally, at least twice a year in my first 15 years of inspecting, I would get to the peak of the roof and regret why I chose to continue up there when I knew it was going to be very dangerous to get down. As I became a more experienced inspector, I saw no shame in scooting down from a roof on the seat of my pants.
I’ve also noticed that it’s becoming more common for builders to design tall, narrow homes with zero lot lines so that more homes can be built on a tract of land. Many of these developments are getting older and home inspectors are getting more calls to inspect those homes. Roof access at these homes is difficult, even when using a 24-ft ladder, as the gutter line is generally higher than 28 feet.
My First Drone
Over the past several years, I’ve kept an eye on the unmanned aerial vehicles (UAVs), more commonly known as drones, being used in real estate and in the hobbyist market. Although I couldn’t justify buying a $4,000 drone for occasional use and I was too busy to try to develop a drone-oriented business niche, a few years ago I did buy a $100 drone and learned to fly it. Frankly, it was a humbling experience as I did not grow up with a Nintendo controller in my hand. My $100 drone had a camera, but it didn’t hover and the wind above the roof peak pushed it around. It also did not have a “return to home” function, which I later learned was invaluable. If the drone drifts off and you cannot tell the orientation, there is no easy way to bring it back. For example, I live on a hill, so on several occasions I had to do forced landings and then go out on my bike to locate where the drone landed. I can tell you it wasn’t fun peeking over fences to find the little drone.
Drone Upgrade 1
In 2017, Costco sold a DJITM Mavic Fly More Combo for less than $1,000. DJI had solved the size problem, so I grabbed this one and set about learning to fly it. A DJI Mavic is much smaller than a DJI Phantom; the Mavic weighs 1.6 pounds and folded up, it fits in the palm of my hand. The Mavic is really a technical marvel with flight stability and collision avoidance. The 3-axis gimbal camera took 12 MP photos. It could also take video with 1080p resolution.
Flying the Mavic compared with flying my first $100 drone was like night and day. The Mavic has auto takeoff and landing, and a return-to-home feature with collision avoidance. The Mavic has sensors and intelligence to go around obstacles such as trees when it is coming home. You can take a Google Earth map and plot a course for it to follow.
Using a Drone for Roof Inspections
The software had so many features for getting cool aerial photos, but what about its usefulness for roof inspections? The Mavic controller works with a smartphone which, in my case, was an iPhone. My phone has a WiFi link to the controller, which talks to the Mavic. The phone can display the camera view or a map view. The phone also displays the health of the drone and prevents you from flying into controlled air space or going above 150 feet in the boundary areas of an airport. As most homes are not more than 75 feet in height, these limitations are not a problem when using a drone to supplement a home inspection.
There are apps for drones, such as B4UFly or AirMap, that tell you about restrictions in a specific area. DJI also has this feature built into its controller software. There have been times when I thought I was in a “good-to-fly” area, but the software said otherwise.
For a normal inspection, it takes me about five minutes to set up the drone. I normally start up the drone first, as it is automatically set up to locate multiple GPS satellites. The drone may also “ask” me to calibrate the compass if I am far from home. As these steps are happening, I can check the drone to see if there has been any damage since I flew it last. Then, I start up the controller, which will connect to the iPhone. Once everything is connected and the drone has established its location, I let it take off.
Standard photos I take with the drone:
- A long shot of the front of the home from about 50 feet of altitude
- Photos of the roof from all compass points or corners
- Other photos to identify issues and close-up photos of those issues
Most of the time, I try to keep the drone in my view. One nice feature on the controller is the hold button. I can hit the hold button to reposition myself and not worry about the drone moving on its own, but there are several challenges to watch out for while using a drone for roof inspections.
Calibrate For Sun and Sight Issues
I don’t have a hood for my iPhone, so watching the drone and looking at the display can be difficult because the sun may block the display; however, if I provide shade for the iPhone display, I may lose sight of the drone. So, I try to find a location out of the direct sun but with a good view of the roof.
Avoid the Fly-away
I’ve lost the Mavic due to what is called a “fly-away.” A fly-away is when the drone takes off on its own. I was in a condominium complex and within 20 seconds of takeoff, the drone started climbing, went between two buildings and was not to be found. This DJI product has a nice feature called “Find my Drone,” but the problem is that it will show the GPS location of the drone, but not its altitude. The area in which I lost the drone had lots of buildings with tall roof, and balconies. The good news is that I submitted my flight log to DJI and they replaced my drone, which was under warranty.
Beware of The Trees and Electrical Wires Around The Home
I’ve had some near misses with tree branches. In many cases, the branches are not big enough to trigger the collision avoidance, so it’s always good to look around before I fly.
The controller and app will do their best to keep you out of trouble, but are they foolproof? No. I’ve crashed my drone several times and I admit it was mainly pilot error.
Another crash was caused by a tree branch, which extended farther over the roof than I thought. You learn a bit with each crash, but given a choice, I would rather crash a drone than take a fall from a roof.
Drone Upgrade 2
Currently, I am flying a DJITM Spark. The Spark, which weighs 300 grams or 0.6 pounds, is smaller than the Mavic. The Spark has the same camera and controls as the Mavic, but it costs several hundred dollars less. The one disadvantage I notice with the Spark is its battery life, which is less than 15 minutes per battery. This hasn’t been much of an issue for residential roofs, as I usually don’t need more than 10 minutes of flight time to get the photos I need.
Recently, DJI replaced the Spark with the Mini. The Mini weighs 249 grams, which is significant because the Federal Aviation Administration (FAA) rules say that users do not have to register drones weighing less than 250 grams.
I’m hoping that the FAA also removes the need for users to have a drone pilot license to use drones weighing less than 250 grams for business. The FAA drone pilot license is primarily oriented to large drones that fly at the same altitude as airplanes. During inspections, it’s rare that I send my drone higher than 75 feet and out of my eyesight. I would really like to see the FAA have another license or registration category for users of smaller drones for business or home inspections.
I have seen numerous forum discussions among home inspectors about the merits of walking a roof versus using a drone. Let me be clear: My preference is to walk a roof.
My eyes and experience can easily detect subtle issues that even a close-up photograph cannot. And a drone can’t lift the edge of the shingles or feel how brittle they are.
However, when the height, pitch or materials of a roof give me concern, I use my drone. Of course, it is critically important to explain to my clients how I have inspected the roof and explain the limitations of the methodology, all of which I state in my inspection report.