A gravel base for a shed requires 4–6 inches of compacted crusher run or crushed stone on a level, excavated pad 12 inches larger than the shed on each side. This is the fastest and most DIY-friendly foundation option—no forms, no curing time, and it drains better than concrete.
Why Gravel Works for Sheds
Gravel foundations are endorsed by many shed manufacturers as a standard foundation option. The Tuff Shed installation guide, for example, specifies a minimum 4-inch compacted gravel base with proper drainage slope. Gravel:
- Drains water away from floor joists, preventing rot
- Adjusts easily if settling occurs
- Costs less than a concrete slab (roughly $2–$5 per sq ft vs. $6–$12 per sq ft for concrete)
- Requires no cure time—you can place the shed the same day
Pad Size Rules
| Shed Size | Recommended Pad Size |
|---|---|
| 6×8 ft | 8×10 ft |
| 8×10 ft | 10×12 ft |
| 10×12 ft | 12×14 ft |
| 12×16 ft | 14×18 ft |
| 12×20 ft | 14×22 ft |
The extra foot on each side keeps runoff away from the shed perimeter and provides a stable edge for the skid runners or anchor brackets.
Crusher Run vs. #57 Clean Stone: Which to Choose
This is the most common point of confusion when building a shed pad. Both materials work, but they have different strengths.
| Factor | Crusher Run (#411) | #57 Crushed Stone (Clean) |
|---|---|---|
| Compaction | Locks into near-rigid surface | Stays looser—won’t compact hard |
| Drainage | Moderate—fines slow water movement | Excellent—water passes straight through |
| Surface stability | Best—skids and blocks stay level | Good, but stones can shift slightly |
| Best site | Firm, well-drained soil | Wet or clay soil; drainage-critical sites |
| Typical cost | $25–$40/ton | $30–$55/ton |
Recommendation: Use crusher run as your primary material on firm, well-drained subgrade—it compacts into the most stable, level surface. On clay-heavy or wet sites, add a 2-inch drainage layer of #57 clean stone under the crusher run so water can escape the pad before the crusher run layer goes on top.
Do not use pea gravel or river rock—rounded stone never locks together and will allow the shed to shift and go out of level.
Materials You Need
Gravel: Crusher run (quarry process / #411) is recommended for most sites because it contains angular crushed stone plus stone fines that compact into a near-rigid layer. For wet or clay subgrades, use 2 inches of #57 clean stone as a drainage base under the crusher run.
Geotextile fabric: Non-woven polypropylene fabric (at least 4 oz/yd²) laid on the excavated subgrade before gravel. This prevents soil migration up through the stone over time.
Edging (optional but recommended): 4×4 pressure-treated timber, landscape timbers, or steel edging around the perimeter keeps gravel from spreading into the yard.
How Much Gravel to Order
Formula: Length × Width × Depth (in feet) ÷ 27 = cubic yards Then add 15% for compaction loss.
Worked example—12×14 ft pad, 6 in deep:
- Volume = 12 × 14 × 0.5 ÷ 27 = 3.1 cubic yards
- Plus 15% = 3.6 cubic yards
- Crusher run weighs ~1.4 tons/yd³ → order about 5 tons
At roughly $30–$45/ton for crusher run plus delivery, plan on $200–$375 in material for this size pad. Use the gravel calculator to dial in your exact dimensions.
Step-by-Step Build
Before you start: Call 811 at least three days before any excavation to have underground utilities marked. This is a legal requirement in all US states and costs nothing.
-
Mark the pad. Use stakes and string to mark the pad outline. Check for square by measuring diagonals—they should be equal.
-
Remove vegetation and excavate. Strip grass and topsoil to a depth of 6–8 inches (6 for the gravel, 2 for settling buffer). A sod cutter ($60–$80/day rental) speeds this up significantly.
-
Check for level. Use a long level or a laser level on the subgrade. Grade so water flows away from the shed location, at roughly 1 inch of slope per 8 feet. Remove high spots; do not fill low spots with loose soil.
-
Install geotextile fabric. Lay it flat across the entire excavated area, overlapping seams by 12 inches and lapping it up the perimeter 6 inches.
-
Add gravel in lifts. Do not dump all the gravel at once. Add it in 3-inch lifts and compact each one with a plate compactor ($80–$120/day rental). A hand tamper can work for small pads under 6×8 ft but is much more effort.
-
Check grade after each lift. Use a straight board and level across the pad to identify high and low spots. Add or remove stone accordingly.
-
Final surface. After compaction, the surface should be firm with minimal bounce when you walk on it. Footprints should barely show.
-
Install perimeter edging. Stake timbers or edging around the perimeter to hold the gravel in place.
Drainage Is Critical
Slope the finished pad away from the shed door, ideally 1/4 inch per foot (2% grade). Water that pools under a shed causes floor joist rot within 3–5 years regardless of pressure treatment. If your site is flat, excavate slightly deeper on the downhill side to create a gentle slope in the gravel surface.
Gravel vs. Concrete for a Shed Base
| Factor | Gravel | Concrete |
|---|---|---|
| Installed cost | $2–$5/sq ft | $6–$12/sq ft |
| DIY difficulty | Moderate | Hard |
| Drainage | Excellent | Poor (pooling at edges) |
| Adjustability | Easy | None |
| Cure time | None | 28 days |
| Longevity | Indefinite (with top-dressing) | 20–40 years |
For most homeowners building a storage shed, a gravel base is the better choice. If you need a garage or a building with a concrete floor, see how-to-pour-a-concrete-slab.
Frost Heave in Cold Climates
In states where the ground freezes—roughly USDA Hardiness Zones 4 through 6 and colder—frost heave can lift sections of a gravel pad unevenly. Water in the soil expands as it freezes, pushing upward against whatever is above it.
A well-draining gravel pad minimizes this risk because water cannot pool and freeze if it drains freely. Key steps for cold-climate installations:
- Use clean angular stone (#57 or crusher run) with geotextile fabric below to prevent fine soil from migrating up
- Grade the pad to drain away from the shed in all directions
- Extend the pad 12 inches beyond the shed on all sides so drip-line water runs off gravel rather than saturating the soil near the pad edge
In areas with frost depths over 24 inches (northern Minnesota, Maine, Montana), some homeowners excavate 12 inches and fill the lower 6 inches with #57 clean stone for drainage, then top with 6 inches of compacted crusher run. The deep free-draining layer keeps ice formation minimal even in hard winters.
Anchoring the Shed to a Gravel Base
A gravel pad provides no inherent anchor against wind uplift. For any shed over 100 sq ft or in an area with high wind exposure (coastal regions, Great Plains), add ground anchors:
Concrete deck blocks: Set precast 12-inch concrete deck blocks on the compacted gravel at the shed corners and every 4–6 feet along the perimeter. Skids rest on these, keeping framing off the gravel and providing some bearing mass.
Earth anchors (auger anchors): Spiral steel anchors driven into the soil below the gravel at each corner connect to the shed frame with straps rated for 1,000–3,000 lbs each. This is the most secure option and is often required by local codes for sheds over 120–200 sq ft.
Rebar stakes through the timber perimeter: Drive 18-inch lengths of rebar through the pressure-treated timber perimeter frame into the soil every 4 feet. This prevents the frame from sliding but does not resist uplift.
Check your local municipality’s shed permit requirements—many counties specify anchor type and number for any structure over a minimum square footage.
Building on a Sloped Site
If your site is not flat, you have two options: cut and fill, or step the perimeter frame.
Cut and fill: Remove soil from the high side down to your target grade, then use the excavated soil to build up the low side. Compact the filled side in 4-inch lifts before adding gravel. This approach works well for slopes up to 12 inches of total rise across the pad.
Stepped timber frame: On steeper slopes, build the perimeter timber frame in steps. The uphill side sits at ground level; the downhill side is stacked one or two courses of timber higher, creating a level gravel surface inside the frame. Fill the inside with gravel and compact normally. This avoids heavy soil disturbance but requires more lumber and careful leveling.