• What Is Ballast? An Ultimate Guide

    | by Holly Wood

    What is ballast? It’s a question that often pops up, yet the answers seldom capture the complete picture.

    Often overshadowed by more commonly mentioned building materials, ballast forms the bedrock of countless structures around us.

    Through this blog, we aim to pull back the curtain and delve deep into the world of this critical material, unravelling its importance, applications, and the integral part it plays in our built environment.

    Let’s begin.

    Understanding Ballast

    Ballast, primarily known as ballast sand in the building industry, is a combination aggregate that comprises a mix of sand and gravel, usually found in a ratio of 50:50 or 60:40.

    Behind the impressive sheds, sturdy fences, and quaint cobblestone paths, lies the unseen and often unappreciated work of this humble building material.

    At its core, it plays a significant role in providing stability and strength to structures around us. How does it do that? Let’s find out below.

    How Ballast Works

    Here’s how it works: The sand and gravel mixture is combined with cement to form concrete.

    When water is added to this mixture, the cement reacts chemically and hardens, encasing the sand and gravel particles and creating a strong and dependable concrete.

    The sharp edges of the gravel and sand in the ballast interlock when compacted, leading to a strong and sturdy bond in the hardened concrete.

    This bond is what makes concrete such a reliable building material, capable of withstanding heavy loads and harsh weather conditions.

    From laying the foundations for buildings to constructing roads and bridges, ballast is a fundamental component that contributes significantly to the longevity and stability of these structures.

    Ballast Types

    It’s also important to note that the characteristics of ballast can vary depending on its source.

    It is often sourced from local quarries and the type of rock used can vary, with some of the most common types being granite, limestone, and trap rock.

    Each type of rock gives the ballast, and consequently the concrete, different properties, making it suitable for different types of construction projects.

    Ballast in Construction Projects

    Creating Concrete: It is primarily used in combination with cement and water to create concrete mix. This mix is versatile and used extensively in various construction activities, such as building foundations, walls, and floors.

    Forming Stable Sub Bases: Ballast is widely used to create firm and stable sub bases for paving and shed bases. Its composition allows for efficient compaction and a robust base that can withstand heavy loads. For applications demanding higher resilience, larger aggregates such as MOT type 1 are typically the preferred choice.

    Erecting Fence Posts and Retaining Walls: The interlocking nature of ballast’s sharp sand and gravel aids in securing fence posts and constructing sturdy garden or retaining walls. In addition, you can use it to form path edgings and kerb ledges.

    What Are The Advantages of Using Ballast? 

    Beyond its functional usage, ballast also offers several advantages, making it an invaluable resource for construction and building.

    1. Versatility: Ballast is exceptionally versatile and finds usage in a variety of construction and landscaping uses. From creating concrete for building projects to providing sub bases for garden walls and securing fence posts, ballast proves its worth time and again.
    2. Robust: Compared to other concrete mix constituents like building sand, ballast is notably heavier. This characteristic not only amplifies its weight but also its texture, making it rougher. Consequently, it strengthens the adhesive property of the mixture, enhancing the overall potency of the concrete paste.
    3. Cost-Effective: Compared to purchasing separate aggregates like sharp sand or gravel, using ballast offers a cost-effective solution. Buying ballast in bulk bag format offers additional savings for those undertaking larger projects. Here at Materials Market, we stock All In Ballast Bulk Bags.
    4. Ease of Use: With the ability to mix concrete at the site, professionals have the flexibility to create the exact concrete mixes needed. This means you can adjust the mix on a project-by-project basis, ensuring you always have the most dependable concrete.
    5. Sustainability: Many local quarries produce ballast, making it an environmentally friendly choice due to reduced transport emissions. Plus, by using natural aggregates, we’re turning to resources that the Earth readily provides.

    How Much Ballast Do You Need?

    When undertaking projects involving bagged products, the question of “how many bags?” frequently surfaces.

    This can be quite a subjective topic as the quantity required can vary depending on the construction project and the preferred concrete mix ratios.

    A rough rule of thumb is to use a 6:1 ratio of ballast to cement for making concrete.


    In conclusion, ballast is far more than just a mix of sand and gravel. It’s a foundational building block that gives our structures strength and resilience.

    Through our exploration of this pivotal building material, we’ve seen how it serves as a backbone for an array of construction projects, offering adaptability and functionality that few other materials can match.

    From creating robust concrete to forming stable sub bases and enhancing our landscapes, ballast’s versatility truly shines through.

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