Step-by-step gravel shed foundation

When a gravel base is right

Gravel suits most timber, metal and plastic sheds up to about 10x8 ft. Check these four things first.

Shed sizeBigger sheds and workshops with heavy benches need slabs or concreteUp to 10x8 ft
TimeDay one to dig and build the frame, day two to fill and level2 days
GroundFirm soil with a gentle slope; on soft clay or a steep slope, ask a builderUp to 100 mm fall
SkillsDigging, measuring, a straight saw cut and a drill-driverBeginner

A heap of angular crushed stone, the size used under a shed base

Build the base in 7 steps

Measurements are for an 8x6 ft shed. For another size, keep the same margins and depths.

1
Mark out the area
Peg out a rectangle 150 mm bigger than the shed floor on every side: 2.75 x 2.15 m for an 8x6. Measure both diagonals; when they match, the corners are square.
2
Dig out turf and topsoil
Remove 100 to 150 mm of soil, roots and all, and keep the bottom flat. Tread or tamp it firm; loose soil sinks later.
3
Build and level the frame
Screw 150 x 47 mm treated timber into a box at the pegged size. Set it level both ways with a spirit level, packing or digging under it, then fix it to stakes driven inside.
4
Lay the weed membrane
Line the bottom with landscape fabric, overlapping joins by 150 mm, and staple it up the inside of the frame. It stops weeds and keeps gravel from mixing into soil.

Close view of grey angular gravel about 20 mm across

5 Fill and compact the gravel

Use 20 mm angular stone, not round pea shingle, which rolls. Fill in two 50 mm layers and tamp each one hard.

Gravel spread flat at ground level with grass at its edge

6 Level the top

Drag a straight board across the frame to screed the stone flush. Check level in both directions and top up any dips.

A grey timber garden shed with a shingle roof standing on a lawn under trees

7 Set bearers and the shed

Lay treated bearers across the gravel, 400 to 600 mm apart, and build the shed on them. Doors that close cleanly mean the base is right.

Materials and tools list

Quantities for an 8x6 ft shed on a 2.75 x 2.15 m base, 100 mm deep.

Materials

Treated timber, 150 x 47 mm4 at 3.0 m
Timber stakes, 450 mm8
Exterior screws, 100 mm1 box of 50
Weed membrane8 m²
20 mm angular gravelAbout 1 tonne
Treated bearers, 75 x 50 mm4 at 2.4 m

Tools

Spade and rake
Spirit level, 1.2 m
String line and pegs
Saw and drill-driver
Hand tamper
Wheelbarrow

Two black builder's wheelbarrows standing on a paved yard

Example budget for an 8x6 base

Typical UK price ranges for the materials list above. Your local merchant may differ.

Example cost of a gravel shed base for an 8x6 ft shed
Item	Example cost
Treated timber frame, 4 lengths	£40 to £60
Stakes and screws	£15 to £20
Weed membrane	£10 to £15
20 mm gravel, one bulk bag, delivered	£75 to £130
Treated bearers	£20 to £30
Plate compactor hire, one day (optional)	£35 to £50
Total, without hire	£160 to £255

Where to save

Buy gravel loose from a builders' merchant if you can collect it; delivery is often a third of the price of a bulk bag.

A hand tamper costs less than one day of compactor hire and does the job on a base this size.

Example product picks

Each pick below is an example of the kind of product to look for, not a tested recommendation. Links marked “Check the price” are affiliate links.

Example pick: plastic base grid kitInterlocking grid you fill with gravel in place of a timber frame. Look for a stated load rating.Check the price
Example pick: heavy-duty weed membraneWoven, 100 g/m² or heavier. Thin non-woven sheets tear under stone.Check the price
Example pick: steel hand tamperA 200 mm square plate on a long handle. Enough for bases up to about 10x8 ft.Check the price

Timber bearers laid across a plastic grid base filled with gravel

Gravel base questions

The questions readers ask most about this job.

See all base articles

How deep should a gravel shed base be?

100 mm of compacted gravel is enough for most garden sheds. On soft ground, dig 150 mm and add a layer of MOT Type 1 under the gravel.

Can I use pea shingle?

Not for the base itself. Round pebbles roll and never lock together. Use angular crushed stone, 10 to 20 mm.

Does the shed need bearers on gravel?

Yes. Bearers lift the floor off the stone so air moves underneath and the floor stays dry.

Is gravel cheaper than concrete?

Usually, by a good margin, and it needs no mixing or curing time. Concrete is worth it for large or heavy buildings.

Will it work on a slope?

On a gentle slope, yes: set the frame level and fill deeper at the low end. Steeper ground needs a retaining edge or piers.