Sand and Soil Foundation Types: Which One’s Are Best?

Every building you have ever walked in to has a foundation upon which it is built. This foundation therefore has to be constructed correctly, efficiently and most importantly safely for it to last. It also need quality sand and soil supplies to coincide.

Each type of soil has its own set of properties which can affect the foundations of a construction project. Generally speaking, soil will always be more stable if it contains more rock and compacted sand throughout it. Below we’ll discuss different types of soils and which ones are ideal for building a good foundation.



Peat is a type of soil that is usually quite dark in color and is easy to compress due to the amount of water it can soak up and hold. However, during the warmer months it can just as easily dry out, and at times even becoming a fire hazard. For these reasons it isn’t the ideal soil for laying a good foundation. The changing structure makes it rather unstable and a poor option for these types of applications.



Like peat, Clay has similarities with regards to drastic structural changes. It stores water quite well like peat, meaning it expands a lot when wet and contracts significantly when dry. It becomes quite pliable when water logged making it easy to be moved and manipulated. As a result, this tends to put a significant amount of pressure on a building foundation as it moves around too much leading to bigger problems down the track.



Silty soil is smooth to touch and has the ability to hold water for longer periods of time due to its consistency of smaller particles. However, because it retains moisture for this longer amount of time, it becomes cold and doesn’t drain properly. This causes expansion and pushes against a foundation, making it weak over time.



Out of all the soil types, Sand/Gavel has the largest particle composition. It’s dry and gritty, and unlike clay or peat, it doesn’t store moisture because it drains easily due to its larger openings. It’s easily compacted and holds together well when moist, and when properly compacted – makes for a good foundation because of its non-water-retaining properties. However, when moist, the particles can and do often lose their friction, making sand/gravel a soil that can be easily washed away, leaving gaps under the foundation over time.



Loam is a combination of sand, silt and clay, and is one of the more ideal types of soil for building a foundation. It is dark in color, and crumbles when handling it. It’s a great option for supporting a buildings foundation because of its balanced properties and composition, and its ability to maintain water at a balanced rate.



Different types of rock such as bedrock, sandstone, hard chalk, limestone and shale all have high bearing capacities. Their stability and depth make them very strong and therefore ideal foundation support, provided they are properly levelled out.



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