Gravel and crushed stone are two very common aggregates for public and domestic landscaping and surfacing projects. What are the differences between the two, and which is the best type to use?
Crushed stone is exactly what the name suggests — stone that has been made by taking large rocks and crushing them by machine. It is usually made from limestone or granite but can be made from any type of local rock. It is then sorted and sized to make sure it is the right type of material for a particular project. It can also be washed clean before being used to ensure there are no impurities or dust in the stone.
The resulting stones will be irregular and jagged and will therefore fit together when compacted to make a strong and stable surface. If it has not been washed, the dust will fill the gaps between the stone to make an even stronger structure. It is also used with a binder to make cement or concrete for road projects.
Crushed stone is ideal for making flat and solid surfaces, especially ones that are intended to be driven upon. It is also frequently used to make horse riding arenas and cycle paths.
Gravel, on the other hand, is stone that has been subject to natural weathering processes. This typically leads to small, smooth pieces of stone, which can also be many different colours. It can be produced in quarries or collected from rivers and creeks.
The fact that the stones are smoother than crushed rock means that they do not produce such a strong and solid surface. This means that the stones can shift beneath a vehicle, especially if it is on a slope. Gravel has better drainage properties than crushed stone but will not be so resistant to weeds growing through it.
Gravel supplies are much more likely to be used for decorative surfaces like paths, patios or driveways, which are not likely to receive too much wear. Even so, it may need to be topped up or repaired over time.
Crushed stone or gravel?
Ultimately, which type to use depends upon your project. A heavy construction project is likely to require crushed stone, whereas a more decorative surface can be made with gravel. If you're in doubt, just talk to your stone and gravel supplier, who will be happy to answer any questions that you have.