Sanding the floor, glacier style

One of our friends had offered to sand the concrete as it is a bubbly and wavy mess, with lots of cracks, holes and raised pebbles. Not quite up to date to current conrete casting tbh (far from it). He does this for a boss, but wasn't scheduled to work today so he passed by to help us out.
Our contractor scoffed at the idea, didn't think it would be easy at all to sand the concrete, but he did not take into account the industrial model sander our friend brought with him (it didn't look like much, but the sander had some serious big cutter teeth discs)

Like a glacier went over a rock bed, excellent, he really knows his job well. I need to bring up a large level tomorrow and go over the floor and see which areas need levelling before we can put down the flooring.

We stripped back the old stairsway up to the attic.....removed all the bits of carpet, and about 5 kilos of staples, nails and dirt. Will be sanded tomorrow.

Slow but steady, we are getting there.