Removing patio sand and sub base before turfing

[Dav0s]

I've spent most of the weekend removing around 8 tonnes of gravel from our garden, with the aim of laying turf eventually. After pulling up the weed membrane underneath the gravel, we have around an inch of poor quality topsoil, then around 2/3 inches of sand, then below that what I think is some kind of sub base of a depth of about an inch. Our neighbour seems to think the whole garden was paved at some point, so I imagine all this was previously below the patio stones.

Firstly, do I need to remove the sand and sub base to lay turf, or can I just put down some fresh topsoil (if so how much?) and put turf on that? Other threads and the internet seem to have mixed opinions, so I'm a bit unsure. Some say the sand will be good for the grass, but the sub base will be bad for drainage...

If I do need to remove the sand and sub base, is there an easy way to do it? The sub base seems to be concrete coloured but is very fine and can be chipped away to a sand consistency. The problem is that it is a very slow process with a spade, but short of getting some kind of heavy duty breaker, I can't think of an easier way. Any ideas of how to tackle this?

Cheers

 

[r896neo]

loosen it up with a pick-axe then add 4 inches of top soil. The sand will be fine if you mix it in with the new soil. An impermeable layer such as concrete would be a big problem but if you can break up whats there enough so it drains then that will be ok.

 

[ivixor]

The concrete layer sounds like a 'dry mix' typically put under paving slabs.

You have no choice really but to dig the whole lot up if you want to do things properly.