I have a very big landscaping/groundworks project that I need some advice on, please let me know if this is not the right place for it!

We have a concrete tiered garden of about 5 tiers. The very lowest tier has recently had a reinforced wall built on it with drainage so that we can back fill the lower tier and have a (relatively) flat lawn that comes up to the two tiers behind it. We have started to backfill it with demolition rubble that was left from previous builders.

We were advised to use it as hardcore which we have done and now need to move on to the next steps but am not really sure how to proceed.

We are also not sure if we will need to dig out more of the concrete or if we can get away with breaking it up and covering with soil and grass.

The area with sand on will need to be dug down more at some point.…