Concrete base for a shed

[Closer]

What preparation do i need to make if I want to lay a concrete base for a garden shed ? Do I have to dig a hole and fill it with hardcore first ?

[Lardybloke]

Yes, dig down about 9 inches, and lay a good six inches of hardcore down, and flatten with a sledgehammer. Make up a frame of planks around the edge of the hole with the tops level and as high as you want the base to be. Fill with concrete, and use a length of timber longer thaan the width of the frame to tamp it down top the right level.

[Handy Mannie]

You don't need to put as much as 6 inches of hardcore down unless you are putting a heavy object such as a car in the shed. Which by the sounds of things it's only a shed. 2" of hard core and 4" of Concrete will be enough & not so sore on the back.