Raised patio - Raised patio question

[bmcfarlin]

I need some advice. Here is a picture of what I'm trying to do:
http://www.capbrick.com/images/photo2.jpg

I was going to build the perimeter like a two course high retaining wall...but I'm not sure if I should set the bottom course in concrete with a Kerb, or just set it atop my crushed aggregate base and backfill it. As you can see, it will be partially buried, so is it really necessary to use concrete?

[Pablo]

No need for concrete if you bed the first course on 50mm of semi dry over a type1 base then you'll be fine. Getting that circle to fit without cuts will be a headache. I would consider using a raft of leanmix concrete to help with consolidating the backfill though. This would lessen the chances of the wall being pushed out when you start compacting all those layers.

[bmcfarlin]

I agree that such a circle would be a headache to complete! Mine will include a much softer curve, but still be elevated two courses high with a single step down on three sides.

Should I consider concrete between the first and second course of the wall? The retaining bricks I'm using have a "lip" on the back-bottom side. This lip SHOULD pretty much lock the upper course in place...but I'm not sure if I should supplement that with concrete.

[lutonlagerlout]

not sure what you mean by concrete between bricks??
I note with interest that bmcfarlin is from Tulsa .Oklahoma,I am not sure how cold it gets in the winter there,but i know a lot of the USA gets really cold and so the concrete base could do with being a bit deeper
persoanlly i would dig our and concrete a foundation say 12 inches wide and 12 inches deep
lay the 2 course of block/bricks
then back fill the lot up to bedding layer height with leanmix
regards LLL