No Fines Concrete

This has nothing to do with the law!
I was asked to put up some fixings and pictures for a client in Calder Crescent, Sighthill.
Many of these blocks of flats are built with “no fines” concrete which I understand is concrete made without sand. The client’s walls looked like they were finished plaster but they were finished concrete and they were almost impossible to drill. Apparently this is well known in the trade.
Fortunately I had taken my trusty B&D mains drill as my battery drill wouldn’t have drilled many holes in those walls. The technique I used was to start with the smallest masonry drill (3.5mm in my case) at the highest speed available. Once a pilot hole was created to the required depth, it was relatively easy to widen it with bigger drills.
Once you have created the hole the fixing is very strong.
Harry