Whether you’re laying a driveway with Gravelrings or protecting tree roots with Groundcell, one of the core decisions you’ll have to make is about your sub-base. It not only provides a stable foundation for your landscaping. It strengthens and supports load bearing capabilities. Prevents ruts. And ensures that your expensive surface layer is not subsumed into the soil. It can also impact drainage. So, choosing the right sub-base for your conditions and the products you’re working with is essential. But how do you know which one to choose?
Five Things to Consider When Choosing Sub-base for Landscaping Projects
The different categories of sub-base
The most commonly used sub-base come from three categories:
- MOT 1: This is typically made up of crushed granite, gritstone, limestone, and/or basalt. Crushed to form easily compactable 40mm particles, it is full of dust and delivers strong load-bearing capabilities. It is widely used in heavy traffic areas.
- MOT 3: Consisting of pure basalt, limestone, or granite, MOT 3 sub-base has a larger particle size. Typically in the region of 40-75mm. It’s frequently used in driveways and under patios, where there is lighter traffic. But many people prefer it because it offers a permeable sub-base solution.
- Bound sub-base: There are also bound sub-bases available, which use a binder to hold the particles together. These can be very strong, but are usually more expensive. They are rarely required in a domestic setting.
The depth of the sub-base
The depth of your sub-base should be dictated by its intended use. For patios and garden paths, you can usually get away with a sub-base of 75–100mm. While areas with heavier use, such as driveways and hard stands, will usually require a thicker layer of sub-base, between 100–150mm. It’s important to keep this in mind when choosing your sub-base material. Because even a small price difference can rapidly add up when you need a thicker layer.
The quality of the materials
While we’ve mentioned MOT sub-bases above, there are other options available. However, MOT – the acronym for Ministry of Transport – type sub-bases are viewed as the industry standard. When you are using MOT type sub-bases, the quality is assured. Other products can be good, but you have to do your research.
Permeability
One of the most important things to know when choosing a sub-base is that not all materials are permeable. If you live in a very dry area with minimal flood risk, this may not be a consideration for you. However, the more impermeable materials are used in the environment, the greater the flooding risk for all. If you are looking for a permeable sub-base, you need to select a MOT 3 type.
Frost protection
Frost heave is the upward or outward movement of the ground, caused by the formation of ice in the soil. On gravel driveways that do employ a properly laid grid system, this can cause ruts and holes to form. In paved areas, it can even lead to slab displacement. A well-constructed sub-base can protect against this. But you must select a material that provides adequate drainage.
Choosing the right sub-base can impact the strength, durability, and cost of your landscaping project. So, it’s always worth spending the time to find the right solution.
Are you looking for driveway and landscaping solutions? Find out more about what Beauxfort has to offer.
