Base for metal shed

Wooden floors can be a haven for rodents underneath. If poss I would erect direct to the concrete base, cover the inside with a quality rubber mat and seal around the outside edge with a cement flaunch.

My next door neighbour just lifted his old wooden shed, on a wooden floor of which there was around a third chewed away and a rat nest underneath.

In article , RW scribeth thus

Yes same here .. our cat knows where his lunch is;)...

A concrete base is the recommendation, don't forget that it needs to be a little larger then the shed itself.

I have such a shed, though the base I erected it on was pre-existing and not ideal.

I would definitely recommend a slab, for three reasons:

1. Structural, though maybe less significant on a smaller shed like yours. A metal shed on loose paving stones would probably blow over in the first real wind.
2. Flatness. If the base is not absolutely true, you'll end up with a nightmare getting the roof together. The "leverage" of the wall height means that even a small degree of out-of-square-ness puts the roof components right out of whack. My base is very slightly humped in one corner (didn't even notice it before) and I had to get very creative with the final bits of roof.
3. If smooth, best chance of a seal between walls and floor. You're right to be concerned about this. My base is slabs on cement, sometimes with sizeable gaps. I sealed the walls to the base with spandy-foam, but it wasn't entirely successful. I've since added a damp-course and wooden floor inside; we'll see how well that lasts.

Note that the instructions lay down a specific size of slab which puts the edges beneath the eaves and hence out of the purely hypothetical vertical rain. Whether this makes any real difference I don't know. The company I bought mine from sent the slab-building instructions through the post a couple of weeks before the shed arrived.

Pete