grass on patio

Hello,
I have a back garden which is just flag stones. I want to turn 3/4 of this into a grassy area. I am wondering if I can just put top soil over the flag stones and then put some grassy turf down, or should I bash up the flag stones and then laydown top soil, or should I be removing the flag stones completely.
Thanks

 

rhi.... best remove the flags,you can use them always elsewhere, just stack them up out of way.. you could never have a good lawn....unless you plan 12" or more... one advantage, moles would have a job getting through flags , lol..

 

Thought as much, thanks Ladybird