The builder probably has about 50 truckloads of concrete coming into
the subdivision each day, i wouldn't be too surprised if that's a
fairly constant number and if they have excess the pretty much just
need to dump it.

My front porch is 5 foot deep in places and it's definitely not got
dirt piled up in there, though it may have some voiding material.

Good point on drilling holes though - i'll need to buy a longer
masonary bit first though.

Graham