Those are some interesting pics. Greg. I've never seen a block wall made in quite that manner.
I wasn't so clear about block vs. concrete. I haven't seen many concrete walls.
The 'block wall' I am most familiar with - a style seen in Illinois, Nevada, and Arkansas, so forgive me for thinking it was the common method - starts with a concrete slab. Or, at least, a concrete footer.
There will be rather short bits of rebar either poking out of this concrete in select locations.. These pieces are likely to be either 3/4" or 1/2" rebar; 5/8" just isn't commonly used. You usually START with a copper wire set in this concrete for the Ufer.
The rebar is run vertically in only a few select locations, usually near corners and doors. Most often, the block is not the primary structure; there's proper steel for that. Block only fills the spaces between the columns.
Usually there are only a few courses of block where rebar is run horizontally. Bottom, top, and one somewhere above the half-way mark seems to be the practice. This rebar is a lot smaller, perhaps 1/2". It's pretty much just laid in a groove that is manufactured into the blocks, tied to the verticals and each other, and buried in mortar.
Windows and doors have a piece of steel- often angle iron- used as a header. (Not always; I've seen 8-ft. garage door spans made without anything but filled block, not even rebar to tie it all together).
That brings up another relevant point: TIME. Whatever is being done today, you can't expect that to have been the way they did it even last year ... let alone during our childhood. There have been major changes. The excuse varies (hurricanes, earthquakes, whatever), but the result is the same .... there's no telling what you'll find.
The rebar generally doesn't sit plumb and level within the block - especially where pieces overlap. It's often bent or tilted. The result is that you can miss the rebar completely in your first three holes, then run into it on the fourth. You need not run into it by much ... just 1/8" of contact is enough to catch your bit or stop your core drill.
(That's right ... I generally use core drills for everything larger than 1/2")
So, punching a hole in block is a crapshoot ... you either have the hole made in a heartbeat .... or it takes half a day. The difference? Rebar. That's why I'm looking for a better way to deal with rebar.
