In general, there is no restriction to the height a retaining wall can be. However, there are various considerations and factors you must take into account in order to know whether you are restricted to a 2 foot wall, or if you can have a 20 foot wall.
In all cases, a retaining wall will need to be custom designed to your property and situation. Not all retaining walls will work for every property, so it’s important to work with designers and builders that can help you in determining which factors are important before a single brick is laid.
How high a wall do I need?
This will depend entirely on your unique property as well as your needs. If you are looking for a decorative retaining wall, height can be anywhere from 24 inches and up. For areas where water runoff and soil sliding is a potential or common issue, a taller and more structurally sound wall may be required.
What bricks are the best?
Smaller retaining walls offer a wider range of brick options than larger retaining walls and those that are engineered. In some cases, you will have dozens of stylish pavers and other landscaping bricks to choose from, while in other cases you may be limited to more structurally stable blocks.
What building codes and regulations are there?
In some areas, retaining walls over a certain height will need to be engineered. In order for you to know whether or not your retaining wall will need to be constructed from engineered plans, you need to first consider the previous factors as well as some of the below factors.
What is the soil like?
Building a retaining wall on hard packed and stable soil is usually much easier than building one on soil that constantly shifts and will need manual packing before construction can start. All soil types can be built on, though some will need manual or mechanical preparation before the wall is built.
Is there a grade?
If your property has a grade, or slope, the process of building a retaining wall will be more involved than if your property was completely level or flat. However, retaining walls can be built on even severely sloped properties, so don’t feel like a grade is limiting your choices.
How severe is water runoff?
Heavy water runoff will have to be taken into consideration before deciding on what style of retaining wall to build. In areas where water runoff is severe and the soil can shift easily, retaining walls may need more structural engineering to ensure they remain where you want them.
What is your budget?
This is the biggest factor in deciding how your retaining wall can be built. Larger budgets will be able to have more choices and can go much larger than smaller budgets can afford. Smaller budgets are limited by brick choices as well as wall size and soil preparation.