Raised patio retaining wall needed?

[celena321]

We are about to start laying a patio of black slate, which I want raised by one step (about 150mm) above the normal ground level and I want the step to be faced with the slate. What is the best way to go about doing this? We have dtp1 to raise the level of the patio. Is it necessary to construct a retaining wall out of the slate before putting down the dtp1 or is it possible to put the dtp1 down first? Probably an obvious answer here but I need to check!

[Rich H]

I would use bricks or dense blocks to build the perimeter, let it go off, fill with type 1 and whacker it. Lay the slate over the whole area and overhang the edges of the perimeter. Cut slate and use mortar to face it onto the brick or block. If it's 150mm over the whole area then two courses of bricks will be just the job, well haunched on the inside.

[Tony McC]

I'm with Rich. Build a simple/cheap retainer, get the sub-base in and compacted, then lay the paving and clad the face of your risers.