Drones are great tools for building envelope inspections. A lot of what we need to look at is up high on a building, or obstructed from view when we are standing on the ground.
Sometimes binoculars or high powered telephoto zoom lenses on cameras can help. But these only work when there’s a direct line of sight (can’t see low-slope roofs from the ground). Also, for parts of the building far from the ground, the perspective (looking up instead of straight on) can mask some conditions.
When it’s important to see something up close, one option is an elevated work platform like an aerial lift or swing staging. These can be terrific for getting a good view, but also quite expensive, and often cost-prohibitive for many projects.
At Copeland Building Envelope Consulting we’ve found using unmanned aerial vehicles, better known as drones, to be a powerful part of our toolkit. We regularly employ professional drone pilots and photographers to document work in progress as well as existing conditions for building envelope investigations.
Drones used for building envelope inspection are small remote-controlled flying vehicles with high-resolution digital cameras mounted on them. The operator on the ground has access to a live feed from the camera via a tablet computer.
Overall images are ideal for documenting job progress and quickly understanding the conditions at the building. However, high image resolution also allows a surprising amount of cropping, or “zoom”, after the fact. This means even after the shot it taken, the viewer can examine details that may not have been explicitly targeted for capture.
It’s also possible to fly relatively close to building features to get a similar perspective to an arms-length survey from a lift. In fact, in many situations it’s easier to get close with a drone due to building geometry. This obviously depends upon the skill of the pilot and the features of the particular drone, but we’ve had great success getting some up-close viewpoints.
An example of when a drone out-performs traditional access methods is internal roof areas. On larger buildings there are often roof areas that are set back a significant distance from the building walls. These may not be easily or safely accessible to walk on. Viewing these internal roofs from an aerial lift can be difficult or impossible due to building geometry and limitations in where the lift can be parked. A drone can easily fly directly over the area to be inspected.
In addition to the benefits described above, a drone inspection is typically more cost effective than a similar arms-length visual survey using an aerial lift or swing stage. The survey can also be completed in a shorter period of time due to the ease of moving the drone to different areas around the building.
However, a drone inspection is not a substitute for a hands-on inspection when one is warranted. There’s no way (yet) to replicate being able to physically touch, prod, and sometimes disassemble parts of the building to identify and solve building envelope problems.
But for many projects, a building envelope inspection by drone is the perfect first step, and delivers great value. If closer inspection makes sense based on the drone fly-by, that effort can then be better focused where it’s needed most.
Aerial photography credit to Prime Aerial Photography of Somerville, MA