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Fish Friendly
This is a naturally occurring product and there can be variations in colour. We always photograph the product after washing because it can be dusty when you receive it.
Protect Your Gravel —
Add Weed Membrane
  • Extends the life of your decorative stone
  • Improves drainage and reduces muddy areas
  • Saves time, effort, and long-term maintenance costs
  • Stops weeds from growing through gravel
  • Prevents stones from sinking or mixing with soil
Weed Membrane Installation Guide

Prepare the Ground

Clear and level the area.

Lay the Weed Membrane

Roll out evenly across the surface.

Secure in Place

Fix with ground pegs.

Add Your Covering

Finish with gravel or stone.

Why Choose Gravel Stabilisation Grids
  • Stops gravel movement
    Prevents rutting, spreading, and sinking
  • Load-bearing strength
    Supports vehicles, driveways, and parking areas
  • Stable walking surface
    Safe for pedestrians, bikes, and wheelchairs
  • Permeable drainage
    Prevents puddles and surface water build-up
  • Low maintenance
    No constant raking or topping up gravel
  • Long-lasting durability
    Protects gravel layer and base structure
How to use gravel grid to stop gravel migration

Prepare the Ground

Mark the area, excavate to required depth, then install and compact a solid sub-base (MOT Type 1 or similar).

Level & protect

Apply a thin leveling layer of sharp sand and lay weed membrane.

Install grids

Place and connect the grid panels evenly across the prepared surface.

Fill with gravel

Fill cells with angular gravel and level slightly above the grid.

Black Basalt Gravel 20mm

The larger size of this hard-wearing volcanic rock. It's colouration is dark grey with a slighty green look when dry but black and a darker green when wet.
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From £4.68

To £183.60

In stock
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Please note: The majority of orders are delivered on the day you select, Occasionally deliveries can be delayed due to unforeseen circumstances beyond our control. If you have someone booked to lay the gravel for you it is always better to aim for delivery before it will be needed to prevent problems.
Grouped product items
Product Quantity Subtotal

Black Basalt Gravel 20mm (Bulk Bag)
£71.28

Attributes:

  • Grouped Thumbnail Text Bagged StandardBulk Bag (800kg*)
£0.00
Subtotal is VAT included.

Heavy Duty Weed Membrane + 20 FREE Pegs
£19.44

Attributes:

  • Grouped Thumbnail Text Weed PreventionHeavy Duty Weed Membrane + FREE Pegs
£0.00
Subtotal is VAT included.

Gravel Stabilisation Grids (10x required for each Bulk Bag)
£153.00

Attributes:

  • Grouped Thumbnail Text Weed PreventionGravel Stabilisation Grids (10x for each Bulk Bag)
£0.00
Subtotal is VAT included.

Black Basalt Gravel 20mm (Poly Bag)
£4.68

Attributes:

  • Grouped Thumbnail Text Bagged StandardPoly Bag (20kg*)
£0.00
Subtotal is VAT included.

Black Basalt Gravel 20mm (50 Poly Bags)
£110.88

Attributes:

  • Grouped Thumbnail Text Bagged Standard50 Poly Bags (1000kg*)
£0.00
Subtotal is VAT included.

Gravel Stabilisation Grids (12x required for each 50 Poly Bags)
£183.60

Attributes:

  • Grouped Thumbnail Text Weed PreventionGravel Stabilisation Grids (12x for each 50 Poly Bags)
£0.00
Subtotal is VAT included.

Black Basalt Gravel 20mm (25 Poly Bags)
£92.16

Attributes:

  • Grouped Thumbnail Text Bagged Standard25 Poly Bags (500kg*)
£0.00
Subtotal is VAT included.

Black Basalt Gravel 20mm (Sample)
£3.96

Attributes:

  • Grouped Thumbnail Text Bagged StandardSample
£0.00
Subtotal is VAT included.
* Approximate weights: Bulk Bags 800kg • Poly Bags 20kg • 25 Poly Bags 500kg • 50 Poly Bags 1000kg. The bag sizes are uniform, but the size, shape and density of the aggregate can affect the perceived volume.
Formed from the lava ejected by volcanoes. Is often known by different names like Charcoal Granite Gravel, Meteor Black Gravel or Ebony Black Gravel. This hard rock has two colour states. When dry the gravel is a mixture of charcoal grey with a hint of green but once wet it becomes black with a slight green tint. The 20mm is ideally suited for most uses but especially on driveways due to its size and hardeness and water features and ponds which bring out the colour. The size range is approximately 15-25mm. The recommended depth for laying is 40-50mm.

Depth for 20mm Graded Aggregates and Gravel

The recommended laying depth for this size is estimated to be between 40mm and 50mm.

More information and examples of other sizes and types of aggregates are available in our Aggregate Depth Laying Guide.

  • 20mm gravel at 50mm deep
  • 20mm gravel at 40mm deep
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