I am thinking about leveling a section of my garden and building a wall to essentially form a rasied bed where once there was a continuous slope. It will be no taller than 2-3ft tall with some steps (made from decking steps) in the middle. I am assuming the wall will be split into 2 L-shaped sections. How deep/wide will the trench have to be? And the concrete bed?
I am also assuming that it will have to be double skinned - is this a fair assumption? Therefore should both skins be brick or can the rear be concrete block? Do the skins have to be bound together? If so how?