Raising height shed base

[Paul-man]

I am reducing the slope of my garden, by adding soil. Probably about 6 inches at one end where there is a shed. I will be replacing the shed with a 7x5 (currently 6x4)

Can I build up the existing Base to the right height by adding concrete on top?
Break it up and start again?
Or bury the old one in couple inches soil, then build new Base on top?

 

[theprinceofdarkness]

So you new shed will overhang the old base by 6" on each side. It is best that the shed sits above the grass/garden so water dripping of it does not splash soil back onto the walls.
The quickest way would be to put down lines of 6" blocks under the floor joists, then put wooden bearers onto of these that extend right to the edge of the shed (overhang by 6"). The trouble is that the wooden floors of cheap sheds drop a lot between joists - at least my OSB floor did. You really need blocks that are 6" high , say 4" wide and of any length. So if you have a disc cutter then cutting 9" X 6" 18" blocks down their length will get you going. An easier way is to use them whole, this would raise the shed by 9"+ 2" for the wooden bearers. Put a DPC on the top of the blocks.
As the floor joists and bearers will carry the weight of the wall and roof of the shed via the overhang its importent that there are enough of them. FWIW My work shop has got floor joists at about 12" centres, my potting shed they are more like 18" centre spacing , so its floor is all saggy.
Frank