20mm Gravel

£142.00 inc. VAT

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Our 20mm gravel is the workhorse of the range: a screened, mostly rounded stone in buffs, greys, browns and soft pinks that deepen as soon as it rains. It spreads easily, drains fast and sits at the top of the size range for drives, which is why the same bag gets used for decorative cover and for groundwork. Good for:

garden paths and drives over a compacted sub-base
borders, gravel gardens and ground cover
bedding pipes and backfilling drainage trenches
soakaway fill and general concreting

Laid around 40mm deep over a membrane it stays put and keeps the weeding down to the odd blow-in seedling. One thing to know before you order: rounded stone rolls, so it needs edging to contain it and it is the wrong choice on a slope, where a crushed gravel would work best.

SKU: 15 Categories: Decorative Stone, Aggregates, Driveway Gravel Tags: 20kg 20mm gravel, 20mm aggregate bulk bag, 20mm drainage gravel, 20mm gravel, 20mm gravel bulk bag, 20mm gravel driveway, 20mm gravel path, 20mm pea shingle, 20mm shingle, pea shingle 20mm bulk bag

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You need ≈ 640 kgs

(0.4 m³)

Note: No compaction/settlement included.
Add 10-20% extra for compaction & wastage if required.

Please see the full listing section below for comprehensive specifications, benefits and uses for 20mm gravel — as well as links to inspirational garden ideas and do-it-yourself guides.

Weight	N/A
Quantity	850kg Bulk Bag

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Overview

I get asked for 20mm gravel more than any other size, and often the client wants two different things out of it: something that looks right in a border, and something that will take a car. This grade does both; the stones come in a natural mix of buffs, greys, browns and soft pinks, and like every gravel it deepens and brightens the moment it gets wet. They are mostly rounded rather than crushed, which makes this stone kinder underfoot than an angular chipping and more mobile than one, and that trade-off runs through everything below. Laid at 40mm over a firm base it is a low-fuss surface. The specifications are next, then the depths and coverage I actually work to.

Specifications

Why Professionals & Homeowners Choose 20mm Gravel

The 20mm grade is where decorative stone and structural stone meet, and that is the whole appeal of it:

The 20mm size sits at the top of the 10 to 20mm range I use on drives and at the top of what is still comfortable on a path, so one product covers both jobs.
Rounded stone is noticeably softer and more forgiving underfoot than crushed angular gravel, which is the honest reason to choose it for a seating area or a path you cross in bare feet.
Water goes straight through it, because the voids between 20mm stones are large enough that the surface does not puddle, and that is the same property that makes it work in a drainage trench.
Colour is the cheap win with this one: a soft buff and grey mix when dry, with the pinks and browns coming forward after rain, and our climate provides plenty of rain.
Good value all-rounder for most garden jobs.

Here are some examples from previous installations:

Applications

Gravel keeps the soil surface dry around the neck of a plant, which is why Mediterranean and grey-leaved things sit so much happier in it than in a bark mulch. Lavender (Lavandula angustifolia), catmint (Nepeta racemosa), sea holly (Eryngium bourgatii) and creeping thyme (Thymus serpyllum) all come through a wet winter better with stone around the crown rather than something that holds moisture there. What it is not for: children's play areas, where you want a proper tested material from our play surfaces range, and anything above a gentle gradient, where rounded gravel simply travels downhill.

Paths and borders take it at 40mm over a membrane, with edging installed first to hold the line.
Drives take it at 40mm over a compacted MOT Type 1 sub-base, with grids if the drive slopes or sees much turning.
Gravel gardens and dry borders suit it, since the stone keeps crowns dry through winter.
Pipe bedding is where rounded stone genuinely beats crushed: it beds a pipe evenly and will not bridge or leave voids under it.
Soakaways and drainage trenches use the voids between the stones as the storage, which is what the 20mm size gives you.
General concreting works, since 20mm is the standard coarse aggregate size for most mixes.

Inspirational Ideas & DIY Guides

What Is a Soakaway? The Simple Way to Improve Garden Drainage

If your lawn turns into paddling pool every time it rains, I have a simple fix.

Ben Parrot

How Much Does a Gravel Driveway Cost?

Calculations and Comparisons

Ben Parrot

How to Lay a Gravel Path That Won’t Sink, Soften or Spread

Thin gravel on a firm base over deep gravel always. How I build one that looks new after ten years.

Ben Parrot

Maintenance

How you handle weeds depends on the setup: on a decorative bed, lay it straight onto the soil before after removing all weeds and roots and then rake lightly every few months to redistribute. On a paving area or driveway, a heavy duty membrane goes over the compacted sub-base instead. For deep cleaning, particularly where algae discolours the chippings, check our guide on how to clean chippings for step-by-step tips.

Purchasing Tips

Quarry batches can vary slightly in the different shades, so it’s best to be prepared for some natural variation. Try to get what you need in the one load. Measure your area in square metres and the use our gravel calculator to get an accurate order.

FAQs

Is 20mm gravel the same as pea shingle?

20mm gravel and pea shingle are the same family of screened, rounded stone, and this grade is sold under both names. Pea shingle more often means the smaller 10mm grade, so buy on the stated size rather than on the name.

Is 10mm or 20mm gravel better for a driveway?

20mm gravel is the better driveway size, because larger stones move less under tyres and are too big to lodge in a tread. 10mm reads finer and is more comfortable to walk on, which makes it the better path stone. Drives want 10 to 20mm and this sits at the top of that range.

How much does a bulk bag of 20mm gravel cover?

An 850kg bulk bag of 20mm gravel covers roughly 13 square metres at 40mm deep, or about 10 square metres at 50mm. Add around 10% for settlement.

How deep should 20mm gravel be laid?

20mm gravel wants about 40mm of depth on anything walked or driven on, which is roughly twice the stone size. Go deeper and feet and wheels sink in instead of skimming across the top. In a border where nobody walks, 50mm blocks more light and holds the weeds down better.

Can 20mm gravel be used in a soakaway or French drain?

20mm gravel works in a soakaway and sits at the bottom of the 20 to 40mm envelope a French drain wants. Rounded stone beds a perforated pipe evenly without bridging, so it suits the pipe zone particularly well, and a 40mm stone stores more water per barrow through the body of a deep drain.

Will weeds grow through 20mm gravel?

Weeds rarely push up through 20mm gravel laid 40 to 50mm deep over properly overlapped membrane, but seed blows in and roots in the stone above it. That top layer is where the weeding actually happens, and it is a few minutes with a hand fork a couple of times a summer.