Levelling Lawn

sandbrook10

Hi

I’ve recently moved into a new home - the rear garden was laid completely to slabs etc when we moved in. We’ve paid contractors to remove the slabs, concrete below and even more slabs / tarmac down to soil level which in some parts is very stony/rough, but on the higher level it’s very good soil

The garden slopes left to right - we want to bring the lower level up about 30-40cm to the top finished height

The area is to raise to meet the higher area is about 30-35m2

If I have topsoil of a depth of 100-150mm what would be recommended for the base c250m2?

Would it simply be layers of soil of could I use sand or shingle to bulk it up a bit before putting soil down as a more economical solution?

Thank you 

Fairygirl

You could certainly use other materials underneath, but it will all tend to settle, so you might need to wait a while before adding the topsoil. The topsoil will also find it's way through gravel, so you may want to add a layer of landscape fabric, or similar, to prevent that. It would be wise to let the topsoil settle too, before seeding or turfing, otherwise you'll end up with hollows and dips, which can be a bit of a nuisance to sort. The proper prep once you're at that stage is well worth it.  It'll be quite pricey to do, whichever route you take. 
It's also worth having some weep holes in whatever the retaining wall is made from, because if you use a lot of gravel, it can act like a sump, and excess water can easily end up sitting in there. Your climate will play a part in that of course