How much ground to clear?

[Dunny1234]

Sorry for the silly question, how much ground do I clear in preparation for the digging of the foundations? I’m clearing an old barn, knocking down walls and breaking up slab, once this is removed, I need to clear the ground down ready for marking out of the footings. I just don’t know how far to go down. 
 

i think 700mm should do, as the FFL is pretty much the same as the current concrete slab. Does this sound about right? 
 

any advice would be appreciated, thanks in advance 

[PeterW]

3-400mm at most assuming you hit solid ground, then just dig out the strip for the founds and back fill with clean hardcore once the brickies have got you to DPC level. 
 

What has the SEng drawn for this as a lot of statements both SEng specs on those drawings.