As you may or may not know, retaining walls are highly versatile and customizable and they help shape incredibly beautiful landscapes. They’re used for various different purposes and they’re of several different types. A retaining wall can protect a property from sliding soil or can hold the foundation of a structure in place. It can also add surface area to the boundaries or a site or help preserve the existing ground.
What is a retaining wall?
Before we get into details we should first define the concept. A retaining wall is a structure that holds soil behind it. The role of the retaining wall and the reasons for building it differ from case to case. In order to be successful in building a retaining wall, you must make the right choices throughout the entire process.
Types of retaining walls and influencing design factors
A retaining wall can be of various different types and each type has its own special characteristics. A gravity retaining wall, for example, depends on its own weight and is usually shorter in height than other types. It’s easy to build and it suits most soil types. A cantilevered retaining wall is usually T-shaped and uses steel-reinforced concrete which is cast in place. This type of wall converts the horizontal pressures exerted on it to vertical pressures on the ground below. Another type is the anchored retaining wall which gains additional strength from cables that are anchored to the rocks or the soil behind the wall.
The factors that can influence the the decision when choosing a type are quite numerous. For instance, the type of soil present on the site can tell you whether a gravity wall can do the job or if it needs to be reinforced in some way. A piling retaining wall is good for soft soil and for tight spaces in general. A slope can also be a factor and then there’s also the height of the wall which definitely matters.
Of course, there’s also the choice of materials which has a big impact on everything. Wood is probably the least expensive option. However, it’s also a material with a short lifespan. As is starts to decompose, the integrity of the retaining wall fades. Other materials such as rocks/ bounders, concrete blocks or poured concrete are more resilient and can last for decades. They’re rigid a d generally not affected by climate change, floods or natural disasters. However, they can be quite expensive.
The cost of building a retaining wall
You can’t really determine how much building a retaining wall will cost until you know all the details. The choice of materials, the type of wall, the size, depth, height and other similar factors can directly influence the final cost. As a general rule, you can calculate the total retaining wall costs by adding up the materials, the labor and the miscellaneous expenses which can refer to things like specific tools required for the job or additional materials needed to strengthen the wall.
How to build a retaining wall
If you decide to do this yourself, we suggest finding someone to help along, preferably someone with some sort of knowledge in the domain or at least willing to offer suggestions and ideas. After all, two minds are better than one (usually). DIY retaining walls can turn out to be pretty fun projects.
- The planning. Start by creating a general plan. At this point you should have the final design or at least a good idea or how you want the wall to look like at the end. Now you can choose the location and locate all the utilities on the site and, if required, contact the companies before you start digging.
- The excavation. Once you’ve marked the location and checked everything else on the list, including the materials required for the steps to follow, you can start digging a trench. How deep, wide and long it should be is up to you to decide based on the type of retaining that you want to build.
- Checking the soil. After you’ve excavated the trench for the wall to follow, it’s important to check the soil. This will help you determine whether it has the required allowable bearing capacity specified in the design. Make modifications to the design and reinforce the wall if necessary.
- Prepping the base. For this part you can use gravel or some other material. If you’re not sure about this, check with a professional or have a look at some tutorials that match the type of wall that you want to build.
- Placing the drain. Unless the wall is built to retain water, it needs to have proper drainage and you need to plan for that from the start.
- Setting the layers. This part may differ according to the materials and the type of wall you’ve chosen. This is when you should frame and set the wall or start to form layers using the bricks or blocks that you’ve selected.
- Finishing touches. Once everything is in place, you can fill the space behind the wall with soil and then finish the front or cover the top of the wall with moss for example.
Did you know?
Despite their reputation as utilitarian structures, retaining walls can also be used to create beautiful and diverse landscape designs. You can use them to create a terraced garden, to frame a yard or to add some dimension to a flat and boring site.
Retaining walls don’t have to be straight and linear. In fact, they can take any shape you want. It’s actually quite easy to build a curved retaining wall that follows the shape of a site or that simply looks more organic and in sync with nature and the surrounding landscape.
Larger walls need the help of an engineer. You might be able to plan and build a small retaining wall by yourself but as it grows in size it becomes a more difficult and challenging project. In addition, you may have to check with local building codes if the wall is more than 4 feet tall.
If you plan on building a terraced garden or if the site is sloped, you should start low and then gradually move up, adjusting the techniques and proportions as you go.
Manufactured blocks and stones are better if you want to obtain an even-looking base and a retaining wall with a consistent look and matching colors. On the other hand, if you’re aiming at a natural and organic look, imperfections are your best friend.