How to Lay Decorative Stones in Your Garden: Step-by-Step

Poor ground prep is the reason 90% of DIY stone-laying jobs fail. Invest time here and everything else is straightforward.

Clear the Area

• Remove all existing vegetation — turf, weeds, ground cover. Use a sharp spade to strip turf, cutting 30–40mm below the surface to get the roots
• Treat stubborn weeds — for deep-rooted perennial weeds (bindweed, couch grass, dandelions), apply a glyphosate-based systemic weedkiller and wait 10–14 days for it to take full effect before proceeding. Don't skip this — these weeds will push through membrane if the roots are alive
• Remove all debris — old roots, buried rubble, large rocks. The surface needs to be clean soil

Level the Ground

• Use a steel landscaping rake to level the soil. Fill any dips with spare soil and compact
• Create a very slight fall away from any buildings — roughly 1:80 (12.5mm per metre) is sufficient to prevent water pooling against house walls
• For larger areas, compact with a hand tamper or plate compactor. Loose soil will settle over time, creating dips in your stone surface

If your soil is heavy clay and prone to waterlogging, consider adding a 25–50mm layer of MOT Type 1 sub-base and compacting before laying membrane. This dramatically improves drainage and prevents the "mud soup" effect that waterlogged clay produces.

Weed membrane serves two critical functions: it prevents weed growth and stops stones sinking into the soil. Never skip this step.

Choosing the Right Membrane

Membrane Weight	Typical Price	Best For	Lifespan
50gsm (light)	£8–£12 per 10m roll	Temporary applications, under planters	1–3 years
95gsm (standard)	£15–£25 per 10m roll	Most garden decorative stone applications	5–10 years
125gsm+ (heavy-duty)	£25–£40 per 10m roll	Driveways, high-traffic areas, under pale stone (Bianco Carrara White Gravel, Snow-White Thassos Pebbles)	10–20+ years

For most garden applications, 95gsm is the sweet spot. It's heavy enough to suppress serious weeds and durable enough to last 5–10 years without degrading.

How to Lay It

1. Roll out membrane across the prepared area, smooth side facing up
2. Overlap all joins by at least 150mm — weeds will find gaps. For extra security, tape joins with membrane joining tape
3. Secure with galvanised U-pins — every 300mm along edges and every 500mm across the centre. Wind can lift unsecured membrane before you get stones down
4. Trim edges — leave a 50mm overlap at boundaries that will be hidden by edging or borders

For Planting Areas

If you want to plant through the membrane, cut a cross (X) shape with a sharp knife. Fold the flaps back, plant, then fold them back down around the stem. This maintains weed suppression while allowing your plant to grow through.

Getting the depth right is crucial — too shallow and you'll see membrane showing through; too deep and you're wasting money and creating a difficult surface to walk on.

Depth Guide by Stone Size

Stone Size	Recommended Depth	Coverage per Tonne	Example Product
12–16mm fine gravel	30–40mm	~18–20m² at 30mm	Bianco Carrara White Gravel (12–16 mm)
14–22mm angular gravel	40–50mm	~12–15m² at 40mm	Black Basalt Gravel (16–22 mm), Silver Granite Gravel, Copper Rosso Verona Stone Gravel
20–40mm pebbles	40–50mm	~10–12m² at 50mm	Akron Pebbles, Bianco Carrara Pebbles, Giallo Siena Pebbles
40–60mm cobbles	50–75mm	~8–10m² at 60mm	Rainbow Sandstone Pebbles (30–60 or 60–100 mm), Silver Granite Pebbles – Cobbles (30–60 mm)
60mm+ large cobbles	75–100mm	~5–7m² at 100mm	Grey Fish Pebbles (60–120 mm), Silver Granite Pebbles – Cobbles (60–120 mm or 70–170 mm)

Laying Process

1. Tip stone onto membrane — don't dump entire bulk bags in one spot. Distribute smaller amounts across the area
2. Spread with a steel rake — work the stone to an even depth across the whole area
3. Check depth — push a ruler or stick down to the membrane in several spots to verify consistent depth
4. Top up thin areas — it's easier to add a bit more than to remove excess

For areas visible from windows or seating areas, spend extra time ensuring the surface is truly level. Uneven stone depth is very visible from above and creates a messy appearance.

Angular slate-family chippings such as Black Slate Gravel or Maple Bark Gneiss Gravel behave like other crushed gravels for depth — aim for full coverage so pieces interlock. Not sure which size suits your project? Our pebble sizing guide breaks it down by application, and best stones for borders compares six stocked picks with 20 kg prices.

Without firm edging, loose stone will gradually spread into lawns, patios, and flower beds. Within a year, you'll have a ragged, undefined edge that looks neglected. Proper edging is cheap and quick to install.

Edging Options

Edging Type	Cost	Pros	Cons
Flexible metal lawn edging	£10–£20 per 5m	Near-invisible, creates clean curves, lasts 15+ years	Needs cutting with tin snips
Treated timber boards	£3–£8 per 2.4m board	Easy to install, good for straight lines	Degrades in 5–10 years, straight lines only
Plastic lawn edging	£5–£10 per 5m	Cheap, flexible, easy to install	Can look tacky, degrades in UV
Brick or stone edging	£20–£50 per 5m	Premium look, extremely durable	Requires mortar bed, most labour-intensive

For most garden stone borders, flexible metal edging is the best balance of cost, appearance, and longevity. It sits flush with the ground, is virtually invisible once stones are placed against it, and handles curves easily.

Installation Tips

• Install edging before laying stones — it's much harder to retrofit
• Set the top of the edging flush with the planned stone surface height — not above it, or it looks like a kerb
• For metal edging, use the supplied stakes at every 500mm minimum, closer on curves
• Where stone meets lawn, set the edging 5mm below lawn level so your mower can pass over without catching

Stepping stones through a gravel or pebble area add both function (a stable walking surface) and visual interest. Here's the proper method:

1. Dry-lay first — place your stepping stones on top of the gravel to check spacing. Comfortable walking stride for most adults is 600–650mm centre to centre. Walk the route naturally and adjust until it feels right
2. Mark positions — once spacing is confirmed, mark each position with spray paint or a stick
3. Dig trenches — remove stone and cut through membrane at each marked spot. Dig a trench 20mm deeper than the thickness of your stepping stone
4. Prepare the base — tamp the soil at the bottom of each trench firmly. Check with a spirit level
5. Mix mortar — 5 parts sharp sand to 1 part cement (OPC), mixed to a thick but workable consistency. You need roughly one bucket of mortar per stepping stone
6. Lay stones — spread a 20mm mortar bed in the trench, place the stepping stone, and tap down with a rubber mallet until level. Check level in both directions with a spirit level
7. Set level — the stepping stone surface should be 5–10mm above the surrounding gravel level. This prevents gravel washing over the stones in rain
8. Allow to cure — don't walk on for 24–48 hours to let mortar set

After stepping stones are set, backfill decorative stone around them up to the stone edges. For the surround, Black Basalt Gravel or Silver Granite Gravel gives a stable, walkable surface; for a softer look use Kronos Pebbles or Japanese Flat "Greige" Pebbles. The combination of crisp stepping stones through decorative aggregate is one of the most effective garden design techniques — and it's a single-weekend project.