Last Modified: February 12, 2024

20mm Gravel

The Ultimate All-Rounder Aggregate

Close up of quartz pea gravel

By Ben Parrot - Landscape Gardener & Amateur Geologist

Classification:

Stone landscaping material and construction aggregate

Geological name(s):

Quartzite

Other Name(s):

20mm pea gravel, 20mm driveway gravel, 20mm quartz gravel, quartzite pea gravel, gravel quartz, quartz gravel, quartz pea gravel, flint gravel 20mm

Overview

Welcome to the only encyclopaedia for decorative aggregates and landscaping materials and our listing about 20mm gravel. In the world of construction aggregates and garden landscaping, quartz pea gravel is the default when an industry-type simply mentions "20mm gravel" without specifying the stone. This versatile and widely used material serves a dual purpose, as an economical and versatile construction aggregate and a visually appealing decorative element. Whether it's referred to as gravel 20mm or 10mm gravel, there's a very good chance quartz gravel is what they mean.

This is a comprehensive product page about 20mm quartz pea gravel, a hardscape and construction aggregate. It details the product's specifications, accompanied by photographs, and outlines its benefits, applications, and incompatibilities as a landscaping material. Additionally, this entry serves as a gateway to a wealth of DIY resources, with a list of comparable alternatives, articles offering design inspiration and fundamental principles, and a collection of straightforward, step-by-step instructions for constructing your own hardscaping features.

20mm Gravel Specifications

material

colour

shape

sizes

fall safety

price

Quartz

10- 20mm

durability

fish friendly

eco friendly

degradability

ph

diy friendly

Non-degradable

Neutral

Material

Metamorphic rock

Colour

Brown with a slight variation of white and stone hues

Shape

Rounded to sub-angular

Close up of 20mm gravel

Size Range

10-20mm (0.4-0.8")

Gravel 20mm, pea gravel 20mm, 20mm gravel driveway,
20mm pea shingle, pea shingle 20mm, quartz gravel 20mm, quartz pea gravel 20mm

Fall Safety

Unsuitable for play surfaces

Price

Economical

Durability

High

Fish Friendly

Yes

Pink 20mm pea gravel close up

Eco-friendly

Yes

Degradability

Non-degradable

pH

Neutral

DIY-Friendly

Yes

Gravel 20mm garden path

Benefits

In landscaping, 20mm gravel's attractive appearance and versatility effortlessly transform outdoor spaces, enhancing aesthetics and enabling creative design possibilities. Its excellent drainage properties make it an ideal choice for preventing water buildup around plants and structures. In garden beds, it aids in retaining moisture and regulating soil temperature. The ease of installation and low-maintenance further add to its appeal, making it a practical and visually appealing option for a wide range of applications.

20mm gravel's durability and natural resistance to weathering ensure long-lasting performance in construction projects, providing stable foundations and drainage solutions. When used as an aggregate in concrete, it not only reduces material costs but also enhances the overall performance of the mixture. Its shape allows for better distribution within the concrete matrix, reducing the amount of cement required while maintaining structural integrity, improving workability and reducing shrinkage cracking in concrete. The cost-saving aspect is particularly advantageous in large-scale projects.

  • Inhibits weeds
  • Improves drainage
  • Hard-wearing
  • Eco-friendly, sustainable
  • Low-maintenance
  • Moisture retention
  • Versatile all-rounder
  • pH neutral
  • Concrete cost-saver
  • Safe for aquatic life
  • Pipe bedding
  • Easy to lay

Applications

Whilst generally both quartz rock, 20mm gravel and 10mm gravel have different characteristics that make them better suited for specific applications in both landscaping and construction. 20mm gravel is often favoured for applications where durability, load-bearing capacity, and stability are crucial, such as driveways, foundations, and construction-related projects. It is also used when a more substantial and natural appearance is desired in landscaping features like rock gardens and dry riverbeds.

However, 10mm gravel may be chosen for applications where a finer texture or a smoother surface is preferred, such as certain types of pathways or decorative landscaping. 10mm can be also be used in filtration systems to screen finer materials than 20mm gravel, for example.

The use cases for gravel can be categorised into decorative landscaping and construction applications.

Landscaping Applications

When it comes to landscaping, 20mm gravel is an economical material with a wide range of uses. Its size, shape and texture make it a solid choice for various outdoor projects, adding both functionality and a natural look to your outdoor spaces. Here are some typical landscaping applications for 20mm gravel:

  1. 1
    Walkways: 20mm gravel is a very economical way to create natural-looking and functional pathways and walkways in gardens, parks, or around your home. However, while 20mm crushed gravel can provide a very sturdy surface, 10mm gravel's small size provides a more comfortable walking surface for bare feet.
  2. 2
    Driveway: As a decorative topping for driveways, 20mm gravel provides a durable and stable surface. Plus, the stones won't get stuck in your tyre treads, which can happen with the 10mm size!
  3. 3
    Garden Borders: Gravel can be used to create decorative borders around flowerbeds, shrubs or trees. It provides a clean and defined edge and performs a range of tasks that minimise maintenance.
  4. 4
    Decorative Features: Incorporating 20mm pea gravel around fountains, garden ponds, or as a decorative mulch in planters creates a natural look that complements various landscaping elements.
  5. 5
    Landscaping Features: 20mm gravel can be creatively used to construct dry riverbeds and rock gardens or fill gaps between stepping stones or pavers, contributing to the overall visual appeal of your landscape.
  6. 6
    Erosion Control: While 10mm gravel is often used for erosion control, 20mm gravel can be employed in areas with higher water flow or more significant erosion issues where larger stones are more effective in stabilising slopes and preventing soil erosion.

Construction Applications

Quartz pea gravel is a popular aggregate used in the construction industry due to its unique characteristics and versatility. Its compact nature and interlocking qualities make it an excellent choice for creating a stable and strong foundation in concrete and asphalt. Additionally, its ability to facilitate proper drainage in these applications ensures durability and longevity of the structures.

  1. 1
    Foundation and Base Layers: 20mm gravel is typically used for constructing a solid foundation or sub-base for various structures, including roads, sheds, patios, and driveways. Its larger size provides better load-bearing capacity and stability compared to 10mm gravel.
  2. 2
    Concrete Aggregate: Coarser 20mm gravel is often used as an aggregate in concrete mixtures, especially for projects that require higher strength and durability. It provides structural support to the concrete.
  3. 3
    Trench Drains and Drainage Systems: In drainage systems and trench drains, 20mm gravel is preferred due to its larger size, which allows for better water flow and drainage while preventing clogging.
  4. 4
    Soakaway: 20mm pea gravel is chosen for soakaway systems due to its ability to facilitate water infiltration and filtration, reducing the risk of flooding.
  5. 5
    Drainage: In drainage systems, whether standalone or in French drains, 10mm gravel facilitates water drainage, preventing waterlogging and soil saturation.

In the following section, we list many common 20mm gravel uses and wherever there is a hyperlink beside an item, an article from Outdoor Aggregates about the topic is available.

Shingle garden

Inspiration and Informational Articles

DIY-Friendly How-To Guides

Need to work out how many stone chippings your  project needs? Try our free gravel calculator.

Other Applications

Some other excellent applications for 20mm gravel include:

  • Base for terrace, patios or outdoor seating areas
  • Foundation stability, providing proper drainage when used as a base material for foundations
  • Concreting
  • Sub-base
20mm pea under garden leaves. Jpg

Unsuitable For

The following list represents the kinds of applications that 20mm gravel may not be suitable for:

  1. 1
    Areas with fine plantings: If you have creepers or low-growing plants in your garden gravel can make it harder for these plants to thrive, as it may interfere with their root systems as they try to grow.
  2. 2
    Play surfaces

Similar Alternatives to 20mm Pea Gravel

The following is a list of decorative aggregates which are alternatives to 20mm gravel. They may offer you a more suitable variation on the primary colour, a more economical option, or a close substitute for cases where the base material may be unsuitable for the project you are creating, e.g. limestone is not fish-friendly, where slate is.

Name

Colours

Material

Size

Shape

Availability

Price

buff, white

10-20mm (0.4-0.8")

angular

UK, USA, EU

grey speckled

Granite

3-20mm (0.12-0.8")

angular

UK, USA, EU

pale yellow

5-20mm (0.2-0.8")

angular

UK, USA

black, white, grey, red

6-20mm (0.25-0.8")

angular

UK, USA, EU

golden, brown

Flint

10-20mm (0.4-0.8")

rounded

UK, USA

white

6-20mm (0.4-0.8")

angular

UK, USA, EU

Under £80

£80-£120

£120-£150

£150-£200

£200-£300

£300+

Maintenance

Cleaning dirty garden stones

When used with weed control fabrics installed underneath to suppress weeds, 20mm gravel can significantly reduce the time spent on garden upkeep, with most work limited to raking and the occasional removal of debris. It is recommended to occasionally power wash the product in order to maintain its original colour and prevent the buildup of algae or moss. Natural quarry materials may also have dust which should be washed off with water during installation. For areas with heavy foot traffic, such as paths or footpaths, replenishing the gravel may be necessary over time to maintain depth and coverage.

For more on how to clean gravel, read our article: how to clean garden stones.

Purchasing Tips

Gravel garden with slate paddlestone edging. Jpg

When purchasing 20mm pea gravel, consider the size options and quantity necessary for your project. Where available, it is cost-effective to request a sample to assess the stone's colour and quality against your design requirements. Also, consider the different sizes; for instance, gravel 20mm is typically used for driveways, while smaller 10mm and 6mm gravel is better suited to footpaths.

Our gravel calculator will give you a quick and unbiased estimate for your project needs just by taking a few measurements of the space. It is one of the best and easiest ways to order the right amount and helps avoid shortfalls or over-spending. Purchasing a 20mm gravel bulk bag or ordering in loose loads can offer better value than purchasing in smaller, 20mm gravel 25kg bag sizes. Therefore, calculating accurately can save both time and money. It is also important to consider the delivery aspects, including vehicle access to the site. Additionally, you should check stock availability and factor in VAT and transportation costs if applicable.

FAQs

What is quartz gravel?

Quartz gravel is a naturally occurring aggregate, primarily composed of quartz, known for its durability and a variety of applications in landscaping.

What do you put under pea gravel?

A layer of landscaping fabric or a sturdy base material like crushed stone is recommended under pea gravel to prevent weed growth and maintain stability.

What colours does pea gravel come in?

Pea gravel typically comes in a range of natural stone colours., including variations of brown, white, and grey, reflecting its natural stone composition.

How much is a ton of gravel cost in the UK?

The cost of a ton of gravel in the UK varies depending on size variations on type and quality, but quartz pea gravel is generally economical. It is usually most cost-effective to buy a 20mm pea gravel bulk bag or loose load. Prices vary based on size variations dependent on regional availability and suppliers.

There are many wonderful types of gravel and aggregates available for your project needs. Check them out!

About the author 

Ben Parrot is a landscape gardener and amateur geologist. He is the founder of Outdoor Aggregates, with the mission to create the first encyclopaedia for decorative aggregates. From natural stone through to decorative bark, these aggregates are critical to garden and landscape design, universally.

The problem: There isn't any place where all the different types of decorative landscaping materials and construction aggregates can be found, nor are the specifications of each type readily available. So, enriched by his extensive experience, and inspired by the timeless elegance and raw beauty of stone and rock, etched by nature's artistry over millennia, Outdoor Aggregates was born.