Sloped garden - Leveling / creating tiers

[nhpb]

Hi, We have a 60ft garden sloping away from the house. Only a small patio at the top is level.

I want to do something to level out 20ft of it near the house and then continue with the slope.

The small retaining wall would need to be appox 400mm in height. I had it in mind to use timber sleepers but would this be the best way or look at blocks / bricks?

 

[foxhole]

I would go with brick.

 

[nhpb]

Thanks, My plan is to retain the patio area, but as the level is too high relative to the back of the house, go down 12-18 inches (some of which will be filled with the patio sub=base - existing is inadequate) and shift the soil further down the garden where the soil is needed. The level area past the patio will have have artificial grass.

My question is, the soil and drainage is pretty poor - clay is not that far down. I plan to install drainage. When I do the levelling our, Should I get shot of any clay or is it fine to use to build up the level further down in the garden?