Are you talking skid like skids that freight is shipped on, or 4x4 or 6x6 pressure treated runners that run the length of the structure?
If you are talking about 4x4 or bigger runners, it'll be fine. That is the way all the sheds you can buy around here are constructed. 10 feet deep would have 5 runners, though you can use more if you'd want if building yourself.

I'm actually talking about building it out of 4x6 pressure treated timbers. Sorry, I should've given that detail.

I know that the 4x6's would handle the load, but I'm concerned about what the "skid" foundation would sit on. I don't want it sinking over time. I'll be putting expensive tools inside and working in there a lot. I'd want it to be as stable as possible.

Is 4 inches of gravel enough?

Thanks

My gut reaction is that you'd be better served by a concrete slab with the appropriately sized footings.

Local code may determine you course of action in any case. Have you checked with the local building department?

Mike

No, I haven't. I probably won't even get to this project till next year. I still have to find out if the old garage slab is still there. Right now I've got a mound of dirt on it.

If the old slab is still there, can I just build on that?