Pea Shingle vs Slate vs Gravel: Which Is Best for Your Garden?
Quick answer: Pea shingle is smooth, rounded stone (usually 10–20mm) — good for paths, borders, and drainage, but it shifts underfoot. Slate chippings are flat, angular, and come in strong colours (plum, blue-grey) — great for decorative borders and mulch, less ideal for walking on. Angular gravel (like 20mm limestone or granite) locks together and is the best all-rounder for driveways because it stays put under tyres. Choose by use: driveways want angular gravel, decorative areas suit slate, general paths suit shingle.
“Gravel” covers a whole family of materials that behave very differently, and picking the wrong one means a driveway that scatters, a border that looks flat, or a path that’s uncomfortable to walk on. The differences come down to shape, size, and colour — and each of those affects how the material behaves in place. This guide compares the three most common choices by look, feel, and best use, and explains why the type you choose also changes how much you need to order. Use the calculator above once you’ve decided.
Pea shingle
Pea shingle is small, smooth, rounded stones — typically 10–20mm — in mixed natural tones of buff, grey, and brown. It’s best for borders, ground cover, drainage layers, informal paths, and decorative pots.
Its strengths are that it’s cheap, natural-looking, good for drainage, and comfortable in the hand. The catch is that because the stones are rounded, they roll and shift underfoot and under tyres, so it’s not ideal as a driveway surface or on slopes, where it migrates and needs regular raking back. On the flat, contained by edging, it’s a good-value, attractive choice.
Slate chippings
Slate chippings are flat, angular fragments of slate, often 20–40mm, in rich colours — plum, blue-grey, and green — that deepen and shine when wet. They’re best for decorative borders, gravel gardens, mulching around shrubs, and feature areas.
Their strengths are the striking colour and the fact that the flat pieces knit together and stay put better than rounded shingle, while also suppressing weeds when used as a mulch. The trade-offs are that the flat, sometimes sharp edges are less comfortable to walk on barefoot and can be awkward underfoot for a main path, and the colour can fade slightly over several years of sun. As a decorative surface you look at rather than walk on constantly, slate is hard to beat.
Angular gravel (the driveway choice)
Angular gravel is crushed angular stone such as 20mm limestone or granite, with sharp faces that interlock. It’s the right choice for driveways, well-used paths, and anywhere that needs a stable surface.
Its key strength is that the angular faces lock together so the surface stays firm under foot and tyre — the main reason it beats rounded shingle for driveways. It does look more practical and less “soft” than shingle, and it needs a proper compacted sub-base under it on a driveway to perform, but for a surface that has to stay put and take weight, angular gravel is the reliable option.
Quick comparison
| Pea shingle | Slate chippings | Angular gravel | |
|---|---|---|---|
| Shape | Rounded | Flat, angular | Sharp, angular |
| Best use | Paths, borders, drainage | Decorative borders, mulch | Driveways, busy paths |
| Stays put? | No — shifts | Fairly | Yes — locks together |
| Walking comfort | Good | Firmer/sharper | Firm |
| Look | Natural, informal | Bold colour | Practical |
| Density | ~1.5 t/m³ | ~1.5–1.6 t/m³ | ~1.5–1.7 t/m³ |
Which should you choose?
For a driveway, use angular gravel over a compacted sub-base — it’s the only one that reliably stays put under a car. For a decorative border or gravel garden, choose slate chippings for colour, or pea shingle for a softer, more natural look. For a path or drainage, pea shingle is cheap and does the job, though angular gravel stays firmer if it’s a well-used route. Many gardens use more than one: angular gravel on the drive, slate in the feature borders, shingle on the informal paths.
Whichever you pick, the quantity you need depends on its density — these materials weigh slightly different amounts per cubic metre, so the same area and depth need slightly different tonnages. The calculator lets you pick the material so the figure is right.
Don’t forget the membrane
Under any of these, a weed-suppressing membrane stops weeds pushing through and stops the stone sinking into the soil below. It’s cheap, quick to lay, and saves a lot of weeding — well worth including under any decorative gravel, shingle, or slate. Never use solid plastic sheeting instead, as it blocks drainage and causes pooling.
Common mistakes to avoid
The main mistakes are using rounded pea shingle on a driveway (it scatters under tyres), choosing slate for a main walking path (it can be sharp underfoot), laying any of them without a membrane (weeds and sinking follow), and calculating quantity with a generic density rather than the one for your chosen material. One more: laying decorative stone too deep — 40–50mm is plenty for cover, and deeper just uses more material without improving the look.
Frequently asked questions
What’s the difference between pea shingle and gravel?
Pea shingle is smooth, rounded stone that shifts underfoot; angular gravel has sharp faces that lock together and stay firmer. That’s why gravel suits driveways, where it needs to stay put under tyres, and shingle suits borders and informal areas.
Is slate or gravel better for a driveway?
Angular gravel is better for driveways because it interlocks and stays put under vehicles. Slate chippings are flatter and more decorative, better suited to borders and feature areas than to a surface cars drive on regularly.
Which gravel is best for walking on?
Angular gravel gives the firmest footing; pea shingle is comfortable but shifts underfoot; slate can be sharp. For a well-used path, angular gravel stays most stable, while shingle suits informal, lightly-used routes.
Does the type of gravel change how much I need?
Yes — different aggregates have slightly different densities, so the same area and depth need slightly different tonnages. Always calculate using your specific material so the weight and bag count are accurate.
Which is cheapest — pea shingle, slate, or gravel?
Pea shingle and standard angular gravel are usually the most affordable; slate and coloured decorative chippings tend to cost more. Prices vary by supplier and region, and buying in bulk lowers the cost per tonne for any of them.
Do I need a membrane under gravel, shingle, or slate?
Yes, it’s strongly recommended. A weed-suppressing membrane stops weeds growing through and keeps the stone from sinking into the soil, preserving both the look and the depth. Never use solid plastic, which blocks drainage.