Step-by-step gravel shed foundation

Why gravel?

Water is what kills sheds. A gravel base lets rain drain straight through instead of pooling under the floor, which keeps the floor joists dry and stops the frame from rotting from the bottom up. It's also forgiving: if the ground shifts a little over the years, you can rake and re-level the stone instead of breaking out a cracked slab.

The version below uses a frame of pressure-treated timbers to hold the stone in place. That frame is what turns a pile of gravel into a proper foundation, with crisp edges that don't spread and a top you can get dead level.

Materials & tools

Quantities below are for an 8 × 10 ft shed on a 10 × 12 ft pad (a foot bigger than the shed on every side, so rain off the roof lands on stone, not soil). Tick things off as you gather them.

Materials

• 4 × pressure-treated 4×6 timbers, 12 ftGround-contact rated. Two get cut to 9 ft 1 in for the ends.
• About 2.4 cu yd of 3/4 in crushed stoneAngular, washed stone (often sold as #57). Not pea gravel.
• Woven landscape fabric, 12 × 14 ftWoven, not the thin spun kind. Overlap seams by 12 in.
• 3 × 1/2 in rebar, 10 ft lengthsCut into 2 ft pins, two per timber plus corners.
• 8 × 10 in structural timber screwsTwo per corner to lock the frame together.
• Landscape staples (a small pack)To hold fabric down while you fill.

Tools

• Tape measure, stakes and string line
• 4 ft spirit level and a straight 8 ft 2×4
• Flat spade, shovel and garden rake
• Wheelbarrow
• Circular saw or hand saw
• Drill with a long 1/2 in bit (12 in)
• Sledgehammer and hacksaw or angle grinder
• Hand tamper or a rented plate compactor

The 8 steps

1. Check the rules and pick your spot

   ~1 hour

   Look up your local setback and permit rules (many places exempt small sheds, but not all) and any HOA rules. In the US, call 811 a few days before you dig so buried lines get marked. Choose the highest, flattest patch you have, clear of overhanging branches and at least 2 ft from fences so you can reach the walls to paint them.

2. Mark out the pad

   ~30 min

   Drive four stakes and run a string line for a 10 × 12 ft rectangle. Square it by measuring the diagonals: when both diagonals match (about 15 ft 7 in), the corners are square.

3. Dig out turf and topsoil

   3–5 hours

   Strip the grass and dig down 4 to 6 in, deeper on soft or clay soil. Pull out roots and big stones. Keep the bottom roughly level and tamp it firm; you're aiming for undisturbed, solid ground.

   Neighbour's tip

   Save the turf. Laid upside down in a corner of the garden, it rots down into excellent topsoil in a year.

4. Build and level the timber frame

   2–3 hours

   Cut two timbers to 9 ft 1 in so they fit between the 12 ft sides. Lay them in the trench, check for square with the diagonals again, and drive two 10 in structural screws through each corner. Level it all round with the 4 ft level on the straight 2×4: scrape soil from under high spots rather than packing it under low ones.

5. Pin the frame to the ground

   ~1 hour

   Drill 1/2 in holes through each timber about 1 ft from each end and in the middle of the long sides. Drive 2 ft rebar pins through with the sledgehammer until they sit flush. This stops the frame creeping as the stone settles.

6. Lay the landscape fabric

   ~20 min

   Roll the fabric across the dug-out area and run it a few inches up the inside face of the timbers. Overlap any seams by 12 in and pin it with landscape staples.

7. Fill and compact in layers

   3–4 hours

   Barrow the stone in and spread it in 2 in layers. Compact each layer before adding the next, either with a hand tamper or a rented plate compactor. Layers matter: a full 6 in dump compacted only from the top will settle unevenly under the shed later.

8. Screed and check for level

   ~1 hour

   Drag the straight 2×4 across the top of the frame to screed the stone flush. Check level in both directions and on the diagonals; within 1/4 in over the length is good. Fill hollows, tamp, and screed again. Then let it sit a day or two and give it one last check before the shed goes on.

What it costs

Example prices for a 10 × 12 ft pad, checked in November 2026 at US home-improvement and landscape suppliers. Stone and delivery vary the most by region, so ring a local quarry or landscape yard as well as the big stores.

These are example figures to help you budget, not quotes. Tools you already own aren't included. For comparison, a poured concrete slab of the same size usually costs considerably more once you add formwork, mesh and a concrete delivery.

Example picks

You can get everything for this job at a builders' merchant. If you'd rather order online, these are the kinds of product worth looking for. They're examples to show what to look for, not tested endorsements.

On the live site, product buttons may be affiliate links: if you buy through one, Shed World may earn a small commission at no extra cost to you. On this page they are placeholders.

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