At 30mm thick you don't need anything under that stone.
If you wanted to have a visible rail as part of your design just conceal a length of steel rectangular tube behind it notched into your end frames. It would make it easier to locate the top of that corner leg you have, but you have no structural issues as is.
I'd do probably 10 larger spans than that every year with no issues. When they get real big we just conceal a bit of steel into the design.
If you wanted to have a visible rail as part of your design just conceal a length of steel rectangular tube behind it notched into your end frames. It would make it easier to locate the top of that corner leg you have, but you have no structural issues as is.
I'd do probably 10 larger spans than that every year with no issues. When they get real big we just conceal a bit of steel into the design.