How to support 2 x 10 on concrete?
Drill baby drill. Drill 1/2" or a bit more for glue or epoxy-fill holes in the concrete &amp; in the bottom ends of the boards, 4 in the concrete &amp; 2 each in the boards. These would receive steel Rebar, big Rod, Threaded Rod, Bar Stainless Steel, etc. I'd guess 4" deep into the concrete &amp; at least 6" into the boards. I haven't done, so you can let me know what works or doesn't.