Shed base: Keeping perimeter gravel in place

Question

I'm planning on building an 8x12 shed with a gravel base. From what I've read, the gravel base should extend beyond the perimeter of the shed at least one foot on all sides, so I'll be installing a 10x14 base (or slightly larger.)

Here are my questions:

1. I'm afraid that over the years the exposed gravel around the perimeter of the shed will move around; weather, the kids playing, etc. will take their toll. The gravel will migrate onto my lawn. Sediment build-up on the gravel base won't look too nice. Is this something that I should be worried about? (I hope that the shed and base will still be in good condition 10-20 years down the line.)
2. If there is concern that the gravel will move. Would it be a good idea to cover the perimeter gravel with landscape fabric or some geotextile? I'll be building a 4x4 frame around the gravel pad, and I could staple one edge of the fabric to the 4x4 frame and the other edge to the shed. I'm imagining that over time this solution will improve the aesthetics and keep the gravel in place. I'd be interested in hearing opinions on the pros/cons of such an idea. In addition, I'd appreciate if anyone could offer advice on what type of fabric to use - would any weed-barrier from Home-Depot work, or should I use something specific. (All the fabrics I've seen are designed as an underlayment, but I'll be using it on top of the gravel exposed to the elements. I'm not sure how it will hold up over time.)

EDIT: I should have described the base better. I don't plan on topping the gravel with a concrete slab, rather I'll leave it exposed - here's an example.

Answer 1

The gravel will definitely be kicked and moved around and will get infested with weeds. Building a border or frame around the perimeter is a great idea but using 4x4's isn't good. Even pressure treated wood will rot in a few years if in contact with the ground. I would think about using some concrete edgers similar to the ones shown below for your frame

Then spread some of the weed deterrent landscape fabric inside the frame and pour your gravel on top.

Better yet, instead of gravel, think bout installing square pavers instead of the gravel similar to the ones below.

You'd need to prepare the surface better and make it flatter so the pavers would fit in level but you'd end up with a base that would last forever. You could then skip the edgers but the landscape fabric would still be a good idea.

Answer 2

I assume you plan to have a concrete slab for the shed.

The usual way is to thicken the edges of the concrete slab to retain the soil beneath. It is called a "turn-down" of the slab on grade (S.O.G).

Ideally, the bottom of the turn-down shoulds be placed at the local frost depth, but in cold regions, sometimes the depth does not justify the proposed use of the slab - merely supporting a shed, the problem of the potential frost heave can then be alleviated by placing gravel below the turn-down to cut-off the path of the upward seepage (thru capillary action), which is the necessary factor for soil to freeze.

I would suggest a vapor barrier be placed on top of a layer of sand, over the gravel base, to keep the floor dry. The sand will protect the vapor barrier from been damaged during the compaction of the subgrade.