If you’re considering redesigning an outdoor space that contains a slope, it’s worth taking a moment to learn about the different types of retaining walls available, and the technology behind them.

The most standard kind available is known as the gravity wall, and uses simple technology. Basically, it uses its own weight to hold the earth on one side of it in place. Because the gravity pulling the earth against one side of the wall is counteracted by the gravity vector of the wall itself, and the resultant reactionary vector keeps everything in place. Walls of this kind are often built by piling stones and with mortar-one of the oldest pieces of landscaping technology known to man. That being said, it’s also one of the least trustworthy, and can easily topple. If you have a large slope to adjust, this may not be the best for you, especially if the soil is loose.

The piling wall, another example of slope correction technology, solves some of the problems that go with the standard gravity wall. To build a piling wall, landscapers or architects dig deep into the soil. The wall itself extends into the ground and so, as long as the material of the pilings or wall can handle the force of the gravity on the soil without bending, the wall can hold a lot of strength. For homeowners with steep hills to deal with, piling retaining walls are a great option.

One of the more common, and perhaps more interesting, kinds of retaining wall is the cantilever wall, which actually uses the very same force that tries to topple the wall to keep it in place. It is often described as an upside down T. The cantilever wall features uses a lever arm – a section of the wall running horizontally at ground level – which creates a stable base for the wall. These walls have a reputation for being some of the sturdiest, but also most difficult to install. If you decide to have a cantilever wall installed, it’s best to hire a professional.