Problem with concrete blocks is that they crumble at unexpected times
and do it in a total failure mode.

Nick Hull wrote:
In article ,
"Bushy Pete" wrote:


As another poster said, don't use bricks, concrete blocks or similar as they
can crumble and collapse. You do not want to be underneath something heavy
trying to hold it up with the side of your head......


Actually concrete blocks are pretty strong, IF you put the holes
vertical and put a 2x on the top (and bottom unless dirt). Concrete is
very strong but will crumble if stress is allowed to accumulate at one
spot.