I have an acquaintance in the construction world, and said how brave or mad the guys who sit astride the beams 30m and more above the ground, trying to remove nuts and bolts etc. when deconstructing. He said the worst job is tying the netting to stop debris falling on workers below. The issue is working with flexible materials and tying reliable knots, at least with nuts and bolts they can concentrate on turning anti-clockwise. He said he much prefers construction as all the materials are new and precision-engineered, whereas older structures are sometimes victims of weathering despite all the anti-corrosive coatings.