As an approximate guide, one bulk bag will cover:

• 10–12m² at a depth of 50mm

• 6.5–7.5m² at a depth of 75mm

• 5–6m² at a depth of 100mm

Garden borders, rockeries, and footpaths commonly require around 40mm to 50mm of decorative chippings, while domestic driveways typically require approximately 50mm to 75mm depending on the ground conditions and sub-base.

These figures are estimates only. Actual coverage will vary according to the bag weight, ground conditions, compaction and the accuracy of the excavation.

Not sure how many bags you require? Call our Rugby team on 01788 866945 with the length, width and required depth.

40mm Celtic Green decorative chippings are intended as a decorative surface, border, or driveway topping. Colour, natural subtle sparkled texture, and angular shape can vary according to the source of the stone.

Excavate the area to the required depth and prepare the ground appropriately. A suitable geotextile membrane may be required to prevent weed growth and stop the subgrade from mixing.

Spread evenly over the prepared sub-base to the recommended depth. Rake or lay by hand to ensure an even, flat distribution across the entire area.

Check the finished surface level and slope to ensure proper drainage away from surrounding structures. Ensure the depth is consistent to prevent exposed patches or uneven surface layers.

Requirements vary according to ground conditions, loading, and the intended use of the surface. Follow the project specification or seek professional advice where appropriate.

Available for collection from our Rugby branch or local delivery using our own fleet.

Bulk bags will normally be delivered by a crane-equipped lorry. Delivery is kerbside and the final offloading position is always subject to safe access and the driver’s discretion.

Please tell us before delivery about:

• Narrow roads or restricted entrances
• Parked vehicles or limited turning space
• Overhead cables, trees or other obstructions
• Soft, sloping or unsuitable ground
• Any other access concerns

Enter your postcode on the product page to check your delivery area. We’ll confirm the delivery date after your order is placed.

What is the difference between 20mm and 40mm Celtic Green Slate Chippings?

The 40mm Celtic Green Slate Chippings feature larger, flatter pieces than the 20mm option. While 20mm slate packs tightly together for smooth footpaths, the larger 40mm size offers a bolder, more textured appearance that is ideal for ground cover on wide borders, rockeries, and larger garden beds.

What colors make up Celtic Green Slate, and how do they change when wet?

Celtic Green Slate offers a distinctive blend of soft sage green, sea-grey, and subtle pale turquoise tones. When dry, the slate presents a subtle, chalky matte finish that creates a natural look. When rain falls or water is applied, the stones turn a deep, glossy emerald green that dramatically highlights surrounding plant life.

Is 40mm Celtic Green Slate fish-friendly for ponds and aquatic features?

Yes, natural slate is completely inert and fish-friendly. It will not leach minerals into the water or alter the pH balance of a pond, making it safe for fish, frogs, and aquatic plants. Washing the slate with fresh water prior to placing it in or around a pond is recommended to remove fine stone dust from transit.

Can 40mm Celtic Green Slate Chippings be used on driveways?

40mm slate is not recommended for driveways. The large, flat pieces can shatter or split under the weight of heavy vehicle tires, eventually turning into small flakes and dust. For driveways, denser angular stones like granite or basalt perform much better, leaving slate for pedestrian paths, borders, and rockeries.

How does 40mm Celtic Green Slate help suppress weeds and retain soil moisture?

The substantial size and weight of 40mm slate pieces form a dense, opaque layer over the ground, blocking sunlight to stop weed seeds from germinating. When laid over a high-performance geotextile membrane, it also acts as a natural protective mulch, reducing moisture evaporation from the soil during hot weather while keeping plant roots insulated in cold months.