40mm Plum Slate Chippings

Bring natural texture and depth to your outdoor space with our 40mm Plum Slate Chippings. Quarried in Wales, this larger decorative slate features a distinctive blend of plum, purple and muted grey shades, creating a striking finish for both contemporary and traditional garden designs.

The chunky, irregular pieces introduce a more pronounced texture than finer slate aggregates, making them particularly effective in ornamental borders, rock gardens, around ponds and alongside architectural planting. Their natural shape creates an attractive contrast against paving, greenery and larger landscape stones.

Our 40mm Welsh plum slate is supplied in approximately 850kg bulk bags or convenient 20kg Maxi Bags, available in packs totalling approximately 200kg, 400kg and 1000kg. Whether you're finishing a small planting bed or transforming a larger garden area, you can choose the most practical quantity for your project.

Decorative Garden Borders

Create a bold, natural ground covering around established shrubs, ornamental grasses and garden planting. The larger slate pieces add texture and definition, helping planted areas stand out against lawns, paving and surrounding landscaping.

Rockeries & Raised Garden Areas

The coarse appearance of 40mm plum slate makes it an excellent decorative finishing material for rock gardens, raised borders and landscaped slopes. Combine it with natural boulders and rockery stones to introduce contrasting sizes and interesting shapes.

Pond Edging & Water Features

Use 40mm slate around pond margins, ornamental water features and decorative water gardens. Its larger pieces provide visual contrast alongside pond edging stones, cobbles and natural rock. When wet, the purple colouring becomes more prominent, enhancing the appearance of water-focused garden designs.

Use an appropriate liner protection layer and confirm material suitability before placing slate in direct contact with pond water or aquatic habitats.

Welsh plum slate is valued for its distinctive colouring, which changes noticeably between dry and wet conditions.

When Dry

The stone displays a softer mixture of dusty plum, pale purple and grey-purple shades, creating a subtle natural finish that works particularly well alongside timber, greenery and neutral paving.

When Wet

Moisture intensifies the slate's colouring, revealing deeper purple and rich plum tones. Rainfall or rinsing can create a more dramatic appearance, particularly around ponds, water features and darker garden planting schemes.

Natural differences in colour, surface markings and thickness are expected and contribute to the individual appearance of each piece.

The quantity required depends on the area being covered, ground preparation and the finished depth of your decorative slate layer.

For our 40mm Plum Slate Chippings, the provisional coverage guide below is based on an approximate laying depth of 50mm:

1 × 20kg Maxi Bag – approx. 0.22m²

10 × 20kg Maxi Bags (200kg) – approx. 2.2m²

20 × 20kg Maxi Bags (400kg) – approx. 4.5m²

850kg Bulk Bag – approx. 9.5m²

50 × 20kg Maxi Bags (1000kg) – approx. 11.2m²

A depth of around 50–60mm is a useful starting point for decorative borders and rockeries, with the finished depth adjusted to accommodate the natural variation in the larger pieces.

For example, an area measuring 4m × 2m = 8m² would require approximately one 850kg bulk bag when laid at 50mm depth, using the estimated coverage above.

To work out your garden area:

Length × Width = Area in m²

Use our coverage calculator above to estimate the quantity of 40mm slate needed and compare the requirements for bulk bags and 20kg Maxi Bags.

These coverage figures are planning estimates, not verified product yield figures. They should be confirmed against the supplied stone's bulk density before being treated as final specifications. Actual coverage will depend on laying depth, surface conditions, particle shape and natural variation.

If you are planning a larger landscaped area or an irregularly shaped border, contact our team with your measurements for assistance.

Our larger-grade Welsh slate is available in several convenient quantities, allowing you to choose between individual 20kg bags and bulk delivery.

10 × 20kg Maxi Bags – approx. 200kg

Suitable for smaller ornamental borders, garden planters and compact decorative areas where manageable individual bags are preferable.

20 × 20kg Maxi Bags – approx. 400kg

A practical option for medium-sized rockeries, raised planting beds and decorative garden improvements.

850kg Bulk Bag – approx. 850kg

A popular choice for larger planting areas, substantial garden borders and full landscaping installations requiring greater quantities of slate.

50 × 20kg Maxi Bags – approx. 1000kg

Ideal for larger projects where individual bags make moving and distributing the slate more convenient than working directly from a bulk bag.

Our slate is a naturally quarried product. Individual stones will vary in size, shape, thickness and colour, while moisture content can influence supplied weights.

Our 40mm Plum Slate Chippings originate from North Wales, an area recognised for its long history of natural slate production.

The stone's characteristic layered structure produces irregular, relatively flat pieces with textured edges. In the larger 40mm grading, these natural shapes are particularly noticeable and create a distinctive decorative surface.

Unlike manufactured decorative aggregates, Welsh slate retains natural markings and subtle differences in colouring. This gives each installation an individual appearance, whether the stone is used in a contemporary courtyard or a traditional cottage garden.

As with many quarried aggregates, a small amount of slate dust may be present following handling and transportation. This can be removed with a gentle rinse or left to wash away naturally during rainfall.

For an attractive, long-lasting decorative finish, correct ground preparation is important.

1. Prepare the location. Remove weeds, vegetation, roots and loose debris from the area.
   
2. Level the surface. Create an even, stable base and ensure suitable drainage for the intended location.
3. Install a suitable membrane if required. A permeable weed-control membrane can help separate the slate from the underlying soil in appropriate landscaping applications.
4. Position larger landscape features first. If using boulders, rockery stones or pond edging, place these before spreading the decorative chippings.
5. Distribute the slate evenly. Spread the 40mm pieces across the prepared area, aiming for a consistent finished depth of approximately 50–60mm where suitable.
6. Finish and rinse if needed. Adjust the stone around plants and edges, then gently rinse away any loose quarry dust to reveal the natural plum colouring.

For sloping areas, use appropriate edging or stabilisation to help prevent movement. Avoid placing slate directly against vulnerable plant stems or blocking drainage points.

The main difference between the two grades is the scale and visual texture of the finished surface.

40mm Plum Slate Chippings are particularly suited to projects where a chunkier, more prominent stone is desired, including decorative rockeries, planted borders and pond surrounds.

For a finer appearance, particularly on decorative paths and general garden landscaping, our 20mm Plum Slate Chippings may be a more suitable alternative.

If you're unsure which size will work best, explore our 20mm vs 40mm Plum Slate Chippings guide for a detailed comparison of appearance, coverage and recommended garden applications.

Looking for a different colour or size? Explore our full Slate Chippings collection, featuring natural plum, grey and green slate in 20mm and 40mm options.