Limestone Chippings

What Are Limestone Chippings? 

Limestone Chippings are a crushed stone aggregate produced from quarried limestone, available in 10mm and 20mm grades - in both 25kg and bulk bags. 

In concrete production, they are used as a coarse aggregate. Their angular shape provides mechanical interlock within the mix, which improves the structural integrity of the hardened concrete. Additionally, limestone has a relatively low porosity compared to other aggregates, which helps reduce water absorption and shrinkage in the final concrete product.

In landscaping and drainage applications, these chippings are highly effective due to their uniform size and free-draining nature. When used in ground cover, beneath paving, or around foundations, they promote efficient water runoff and help prevent water pooling and soil erosion. 

The 10mm size is typically used for borders and finer drainage layers, while the 20mm grade is suited to heavier-duty drainage, driveways, and sub-base material.

Composition

Limestone chippings are produced by crushing natural limestone rock, a sedimentary rock composed mainly of calcium carbonate. The stone is then screened into graded sizes.

• Colour & Texture: As a natural material primarily supplied for its performance as an aggregate, expect variations in colour (typically shades of grey, buff, or cream) and texture. This product is not primarily intended for applications where high aesthetic uniformity or specific decorative quality is the main requirement.
• Shape: Generally angular, which aids interlocking in both concrete mixes and when used as a loose-fill material for paths and drives.

Key Properties

• Drainage: Limestone chippings possess excellent drainage properties when used as a loose-fill ground cover, allowing water to permeate and reducing surface run-off.
• Alkaline pH: A critical characteristic of limestone is its alkaline nature. This will influence soil pH when used in garden or landscaping contexts and must be considered for plant compatibility.
• Initial Dust: Like most quarried aggregates, some dust may be present from processing. This typically washes off with rain or hosing.

Applications

As a Construction Aggregate:

• Concrete Mixes:
  • 20mm Limestone Chippings: Widely used as the primary coarse aggregate to create strong and durable concrete mixes for applications like foundations, floor slabs, driveways, and pathways.
  • 10mm Limestone Chippings: Suitable for concreting applications to produce finer concrete mixes, often used where a smoother finish is desired, for smaller concrete sections, or where reinforcement might be more closely spaced.
• Other Construction Uses: Can be used for pipe bedding or creating a firm base in certain groundworks.

In Landscaping & Groundworks:

• Pathways and Drives: Both 10mm and 20mm chippings are ideal for creating durable surfaces for pathways and drives. They provide a permeable and relatively stable surface when laid over a properly prepared sub-base and weed control membrane.
• General Ground Cover and Borders: 20mm limestone is ideal for ground cover and borders, helping to suppress weeds (when used with a membrane) and create a low-maintenance surface. While "not for decorative use" in a premium sense, its natural stone appearance is often acceptable for these practical applications.
• Drainage Solutions: Their excellent drainage properties make them suitable for use in French drains, soakaways, or as a permeable layer in various landscaping schemes.

Benefits

• Forms Strong Concrete (20mm): Provides the necessary coarse aggregate for durable concrete suitable for pathways, drives, and slabs.
• Suitable for Finer Concrete Mixes (10mm): Allows for the creation of concrete with a finer aggregate content where required.
• Excellent Drainage (as loose fill): Helps manage surface water effectively when used for paths, driveways, or in drainage systems.
• Effective Weed Suppressant (in landscaping): When laid to an appropriate depth over a weed control membrane, significantly reduces weed growth.
• Versatile & Practical: Suitable for a range of functional construction and landscaping tasks.
• Cost-Effective: Offers good performance as a construction aggregate and functional ground cover at an economical price point.

Important Considerations

• Not for Decorative Use: Expect natural variations. While suitable for functional landscaping uses (paths, drives, utility ground cover), they may not be the choice for high-end decorative garden features where appearance is the absolute priority.
• Alkaline pH & Plant Compatibility (Critical for Landscaping):
  • Limestone is strongly alkaline. It will noticeably raise the pH of any soil it contacts or that receives water run-off from it.
  • This makes it unsuitable as a mulch or ground cover directly around acid-loving (ericaceous) plants (e.g., Rhododendrons, Azaleas, Camellias, Heathers).
  • It is best used in areas away from sensitive plants or in gardens designed for lime-tolerant species.
• Suitability for "High-Strength Concrete" (20mm): 20mm limestone is a standard, reliable aggregate for producing strong, durable concrete suitable for most domestic and many commercial applications (e.g., C20/25, C25/30 mixes). For specialist very high-strength concrete (e.g., >C40/50), the specific limestone's own crushing strength and properties would need rigorous verification against the concrete design specification.
• Sub-Base & Membrane for Landscaping: For pathways, driveways, and ground cover applications, a well-compacted sub-base and a quality weed control membrane are essential for stability and long-term weed suppression.
• Natural Variations: Please note that product supplied comes from a natural source and may vary in colour, size and texture. 

Guidance on Choosing Between 10mm & 20mm

• 10mm Limestone Chippings:
  • Better for creating finer concrete mixes.
  • Suitable for pedestrian pathways and can create a more tightly packed surface.
  • Good for bedding smaller pipes or for a slightly more refined look in utility ground cover areas.
• 20mm Limestone Chippings:
  • The standard choice for general concreting applications (slabs, foundations, driveways) to achieve good strength.
  • Ideal for driveways and pathways as a loose-fill surface due to better interlocking than smaller sizes.
  • Excellent for general ground cover and borders due to good coverage and weed suppression capabilities (with a membrane).