There are many jobs in the construction industry that fall under the “dull, dirty, and dangerous” category said to be ripe for automation — but only a few can actually be taken on with today’s technology. One such job is the crucial but repetitive task of rebar tying, which a startup called SkyMul is aiming to completely automate using fleets of drones.

Unless you’ve put together reinforced concrete at some point in your life, you may not know what rebar tying is. The steel rebar that provides strength to concrete floors, walls, and other structures is held in place during the pouring process by tying it to the other rebar where the rods cross. For a good-size building or bridge this can easily be thousands of ties — and the process is generally done manually.

Rodbusters (as rebar tying specialists are called, or so I’m told) are masters of the art of looping a short length of plastic or wire around an intersection between two pieces of rebar, then twisting and tying it tightly so that the rods are secured in multiple directions. It must be done precisely and efficiently, and so it is — but it’s backbreaking, repetitive work. Though any professional must feel pride in what they do, I doubt anyone cherishes the chronic pain they get from doing that task thousands of times in an hour. As you might expect, rodbusters have high injury rates and develop chronic issues.

Automation of rebar tying is tricky because it happens in so many different circumstances. A prominent semi-robotic solution is the TyBot, which is a sort of rail-mounted gantry that suspends itself over the surface — but while this makes sense for a bridge, it makes far less for the 20th floor of an office building.

Keep reading on TechCrunch.com