Gravel Pad Shed Foundation: Size, Depth, Stone and How Much to Order

A gravel pad is one of the simplest and most forgiving foundations for a backyard shed. In most cases you remove the sod and topsoil, build a level frame, and fill it with about 4 to 6 inches of compacted angular crushed stone, making the pad roughly a foot wider and longer than the shed. The stone drains water away from the floor, spreads the load, and resists frost heave better than setting a shed on bare soil. Bigger or heavier buildings, soft clay, and steep slopes may need deeper stone, a stronger perimeter, or a different foundation altogether.

Gravel base calculator →

Why Gravel Works Under a Shed

• Drainage: water runs down through the stone instead of pooling under the floor, which helps keep skids and floor framing dry.
• Load spreading: compacted crushed stone spreads the shed's weight over a wider area of soil.
• Adjustable: if the pad settles a bit, you can add and re-level stone without pouring anything.
• Cost and effort: it's usually cheaper and quicker than a concrete slab, and many homeowners build one over a weekend.
• Permits: some towns treat a gravel pad differently from a permanent slab, though rules vary, so check locally.

The trade-off is that gravel doesn't give you a hard floor at ground level. It's a base for sheds with their own wood or composite floor on skids, not a replacement for a slab under a workshop where you'll roll heavy equipment inside.

How Big Should the Pad Be?

A common rule of thumb is to make the pad about 12 inches larger than the shed on every side, so a 10 x 12 shed sits on roughly a 12 x 14 pad. That extra margin catches roof drip, keeps the skids off the soft edge of the stone, and gives you room to walk around the building. If the shed has no gutters, a slightly wider apron on the drip side helps keep splash off the siding.

How Deep Should the Gravel Be?

Four inches of compacted stone is a typical minimum for small sheds on firm, well-drained soil. Six inches is common for larger sheds, heavier contents, or so-so soil. On a slope, the downhill side will be deeper because you're building up to level. Very soft or clay-heavy soil may call for more depth plus a layer of geotextile fabric under the stone so the gravel doesn't slowly push down into the mud. Our guide to geotextile fabric explains how separation fabric works; the same idea applies to a shed pad.

Situation	Typical compacted depth	Notes
Small shed, firm soil, level yard	About 4 in	Remove sod and topsoil first
Larger shed or heavy contents	About 6 in	Compact in two lifts
Soft or clay soil	6 in or more	Add geotextile fabric
Sloped yard	Varies side to side	Stronger frame or retaining edge on the low side

These are general guidelines, not engineering specs. The shed maker's instructions and your local building rules come first, especially for large buildings.

Best Gravel for a Shed Base

The key is angular, crushed stone that locks together when compacted. Round pea gravel and river rock roll underfoot and shift under skids, so they're poor choices for the structural layer. Common options:

• Crusher run / dense-graded aggregate: a mix of stone sizes and fines that compacts very firmly. Great for strength, but the fines drain more slowly. See our crusher run guide for what's in it.
• Clean 3/4-inch crushed stone (often sold as #57): drains freely and still locks together reasonably well. Many shed builders like it because water never sits in it.
• A combination: dense-graded stone for the lower layer and a thin top layer of clean crushed stone for drainage and easy leveling.

Names and sizes vary by quarry and region, so describe what you want (angular, crushed, about 3/4 inch) when you call the supplier.

Step-by-Step Build

1. Check rules and utilities. Confirm setbacks, permit needs and HOA rules, and call 811 before digging.
2. Mark the pad. Stake out the corners and square them by measuring diagonals.
3. Strip sod and topsoil. Organic material rots and settles, so remove it down to firm soil.
4. Grade and compact the subgrade. Tamp the soil so it's firm and roughly level.
5. Build the frame. Pressure-treated lumber rated for ground contact is common; stake it in place and level it.
6. Lay fabric if needed. Run geotextile across the bottom and up the inside of the frame.
7. Add stone in lifts. Spread 2 to 3 inches, wet it lightly, and compact; repeat to the final height.
8. Screed it level. Drag a straight board across the frame to get a flat, level surface.
9. Set the shed. Place skids or blocks on the finished pad and check the floor for level again.

A rented plate compactor makes step 7 much easier on anything larger than a small pad; for small jobs, a steel hand tamper works with more sweat. A long 4-foot level and a straight board help you screed the stone flat.

Edging and Frame Options

• Pressure-treated timbers: the most common choice; easy to cut and stake.
• Landscape blocks: tidy and long-lasting, and good for building up the low side of a slope.
• Composite or recycled plastic boards: won't rot but may cost more.
• No frame: possible on flat ground, but the edges tend to spread over time.

Whatever you use, anchor it well. Rebar or long landscape timber spikes keep timber frames from bowing outward as you compact the stone.

How Much Gravel to Order

Work out the volume first: length x width x depth in feet gives cubic feet, and dividing by 27 gives cubic yards. A 12 x 14 pad at 5 inches deep is about 70 cubic feet, or roughly 2.6 cubic yards. Many suppliers sell by the ton, and a yard of crushed stone commonly lands in the 1.3-1.5 ton range (it depends on the rock and how wet it is), so that pad might need roughly 3.5 to 4 tons. Add a little extra for compaction and waste. Our gravel weight per yard guide explains the conversion, and the base calculator linked above does the math for you. Always confirm the weight per yard with your supplier.

Drainage and Slope

A gravel pad should sit a little higher than the surrounding ground so water flows away rather than into it. If the shed is at the bottom of a slope, consider a shallow swale or a French drain uphill to divert runoff around the pad. Gutters with downspouts pointed away from the pad reduce splash and erosion at the edges.

Gravel Pad vs Other Shed Foundations

Foundation	Good for	Drawbacks
Gravel pad	Most small and mid-size sheds	No hard floor at grade, edges need a frame
Concrete slab	Workshops, garages, heavy equipment	Higher cost, more permanent, often needs a permit
Concrete blocks or piers	Small sheds, sloped yards	Can shift if the soil under each block isn't prepared
Existing pavement	Sheds placed on an old driveway or patio	Drainage and pavement condition matter

If you already have old pavement to use, see our article on putting a shed on an asphalt driveway.

Common Mistakes

• Leaving sod or topsoil under the stone.
• Using round pea gravel as the structural base.
• Dumping all the stone at once instead of compacting in lifts.
• Making the pad the exact size of the shed with no margin.
• Skipping a level check before the shed arrives.

Bottom Line on a Gravel Pad Shed Foundation

For most backyard sheds, a framed pad of 4 to 6 inches of compacted angular crushed stone, a foot larger than the building on every side, is an affordable, well-draining foundation. Strip the organic soil, compact in layers, keep it level, and order stone by the ton after checking your supplier's weight per yard.