Making a base for a shed (Ed.)

[deanalewis]

Heya folks,

I this weekend I cleared a space at the bottom of my garden (dug down about an inch) in prep for a shed. As the soil is disturbed its basically mud the ground I believe is clay.

What would I put on top of this to help create a firm base Im getting conflicting advice.

I can put 20mm aggregate stone and then use a whacker plate over it all to create a more level surface.
or
put crusher run down and then use the whacker plate.

The shed itself cover most of the area but I need the soil stronger again.

Any advice

 

[JohnD]

Is it a wooden shed? What size? Ready made or self build?

Will you be fitting gutters, a downpipe and a water butt with an overflow pipe to take excess water away?

 

[deanalewis]

Its a metal shed and needs a concrete base. Comes with gutters and will have a water butt but the issue is the part of the garden its on is already going to be the lowest point.

 

[JohnD]

The base needs to be raised above ground level so that water does not pool on it. If you are laying a concrete slab, size it so it is just smaller than the shed, so that the shed overhang prevents rain falling on the slab and pooling. If you have an apron at the front, slope it so water runs away,

If you are laying a concrete slab on soft ground it will need to be about six inches deep. To prevent the edges bring undermined, it is best to give it a thickened edge that goes deeper, you can do this by digging a six inch trench round the outside.

I prefer a shed floor to have a DPM to prevent damp rising into the shed. This requires the edges to be made first, perhaps with a couple of courses of bricks, then the concrete poured into a tray lined with DPM

A light shed can be laid on paving slabs, which is easier but not as good.

A metal shed without a floor can be lifted up to steal the contents.

 

[deanalewis]

But what do I do with the soil already there first. its a bit spongy after I dug it back. Should I use a whackerplate add some clean stone then use a whackerplate a second time.

Some places say to lay a membrane down but surely the idea of the clean stone is to add rigidity and to help level out the soil first?

Then after the clean stone is laid can I then put Crusher Run directly on top or do I need to use a barrier between the dirt and the crusher run.

 

[JohnD]

Crusher Run

Are you American?