Thank you Pilou,
Thank you Michael. Now I have understood the purpose of the ISECT operation in the boolean.
I have two things.

1- First I did not understand Pilou's way to make that shape into a solid (See JPG)
2- I am trying to shell the new, all curved, brick shape and cannot do it. See file (shell from bottom). Am I doing again something wrong?

Thank you for your time.
Well appreciated,
Rudy