All it takes is money. Tradespeople all over the world know how to build a room like this because it’s a construction technique used in hospitals for imaging rooms.
I’ve stood in one before the interior surfaces went up - such an insane amount of copper. They had a guard observing it 24/7.
You have to consider this in the context of an active construction site where material handling equipment is strewn about everywhere. 30 pounds is nothing to a pallet jack or a forklift that can go to a telehandler that can put the load in a pickup truck. A wide variety of power equipment is just sitting around, keyed-alike. Thousands of pounds of copper can be gone in a moment to a clever gang of thieves.
Still not a great ROI for the criminal risk being taken, but the people taking this stuff live in very different circumstances than myself and presumably yourself.
I’ve stood in one before the interior surfaces went up - such an insane amount of copper. They had a guard observing it 24/7.