Fortunately, the drone capture provided a big answer. “We had been flying the drone two or three times a week out on that project and were able to go review that imagery and locate every single one of the penetrations coming up. They were able to go out there with a hammer, just chip down through a half inch of concrete or whatever. And sure enough, there they all were.”

Rogers-O’Brien experienced a similar situation on a 19-storey student housing high-rise at a major university. “We had placed all these sleeves for a section of concrete pour and flown the drone over, overlaid the architectural plans with it,” says Holmes.

“We realised that we had something like eight sleeves that were all supposed to be in a wall that were just in the wrong spot. Someone read a tape wrong or pulled from the wrong control line, and those eight sleeves would have been in the wrong spot.”

“It was a high-rise job, so it’s all post-tension concrete and these sleeves sat on either side of some PT cables. So, if they have it in place, it would’ve been very difficult, if not impossible to go to where those sleeves should have been and core out the concrete to place them in place. We would have had to do some rework on the MEP coordination to relocate those.”

Saving money with opportunities

Drones have not only showed value for Rogers-O’Brien in mitigating rework, they have also helped the firm capture potentially missed opportunities and hard dollar savings. One project required the excavation of a very large utility trench, around 3 metres feet deep and 6 metres wide. After the trench was dug, the utilities were installed with room to spare.

“Once they’d laid in utilities that had to go into place, they looked at the aerial imagery and realised they had room to fit another utility in there, so that utility no longer had to have a separate trench dug at a different date. They were able to just come in and install that particular utility in parallel with the other system,” Holmes recalls. By no longer needing a separate trench and installation, the company saved around US$600,000. “Needless to say, that aerial imagery was quite helpful.”

Safety for workers

The versatility of drones also makes them a great tool to minimise risk and increase safety for trades workers and jobsite stakeholders. Case in point, inspections on high-rise projects.

“We’ve performed at least four or five inspections that I can think of that would have meant the mobilisation of swing stages and hanging people 90 metres above downtown Austin to go check some flashing,” Holmes says. “Instead, we just grab a drone and 10 minutes later we have very high-resolution images that we can share with all of our stakeholders, get off to third-party consultants and get to our own in-house risk management experts.”