How to Build a Retaining Wall

The first thing to keep in mind when it comes to how to build a retaining wall is that you may need a permit or some type of approval from your county before taking on this task. Also, it is important to realize that these are basic and general guidelines. Your own yard or the material you want to use for your wall are all factors that can cause slight variations of this how-to guide. For more in-depth solutions, you may even want to get a complete book on the subject. For this quick guide, the steps are for building a retaining wall with retaining wall blocks.

Preparing for How to Build a Retaining Wall

Before actually putting the blocks together to build the wall, you need to take some steps in order to prepare for it. The pre-steps are as follows:

How to Build a Retaining Wall

  • Check the guidelines for codes in your area in relation to building a retaining wall first. In many cases, size of the wall determines whether or not you need permission.
  • Get your utilities marked for your property before you start digging at all.
  • Gather all the materials needed so once you start you can simply keep going with the project.
  • Determine where you would like to put the wall and mark the area. Generally, the best way to do this is to use wooden posts and mark the shape with string.
  • Mark the shape and outline by using spray paint or even just flour.
  • Next you can begin the digging process. Dig an area that is wider than the width of whatever material it is you are using. Generally for stones it is a good idea to go about six inches deep and then level the trench as much as possible.
  • Add a layer of sand and even this out as well. You may also use an alternate substance like stone dust.

Building Your Wall

Now you can begin the process of building the actual wall. Keep in mind this example is using stone but there are many other types of materials you could use. Rocks, wood or even concrete are other common materials people use for wall building.

  1. Set your first layer of blocks, piecing the blocks together tightly. They should be butted up against each other and come as close as possible to creating an even level across as well as front and back. Use a level to check this and lightly tap blocks close together with a hammer. You can use a hammer to help level this first layer as well as set the stones into the ground a bit for more sturdiness.
  2. You will need to start every other level with a half block. Like bricks, when laying the retaining wall blocks you do not want even seams. To alternate the seam or zigzag the pattern, you will need to buy half blocks or split some of the blocks in half. This can usually be done fairly easily by scoring it all the way around with a chisel and then using the chisel and a sledgehammer to split down the center.
  3. Stagger every other row by using half blocks on both ends of the row. Stack your blocks for as many rows or feet high as you intend. Keep in mind anything over about two feet should only be done using certain materials. Also anything over two feet may require special permits and should probably be done by a professional.
  4. The first two rows should be in the trench and therefore you place soil around this base to secure the wall. Keep in mind as you stack to plan on stacking slightly towards the grade. This way any shifting from behind will only cause the wall to begin to be straight instead of tilting the opposite way.

There are different options that can come with completing the wall. For example, when you use retaining wall blocks which are decorative and attractive alone, you will probably want to fill the space behind the wall with landscape fabric. There are also different ways you can start or finish the base as well as create proper drainage.

So keep these things in mind:

  • For certain types of walls, you may want to pour a concrete foundation. In this case, you will need to give the cement a week to dry.
  • Many people fill in the base with gravel or something similar. This is done to offer a strong and sturdy base but also leave room for drainage. Water can still move freely through the gravel to prevent causing a dam type back up effect.
  • The level of slope you are trying to work with will also dictate how difficult the job is. For more extreme cases, you may need to use only certain types of materials. In these cases it is still best to leave the job to a professional.
  • If your property does slope you may also need to dig the base ditch of the wall in a series of step like patterns instead of one long trench.
  • Never place a wall or create the drainage so that the result sends water in the direction of the foundation of your home. Over time, this can cause the need for major and expensive repairs.
  • You should always allow room for some type of drainage. This can be done by making small tunnels the width of your screwdriver and filling these with gravel. The gravel will support the tunnels and also allow water to pass through easily.

Remember, any home project that is a do-it-yourself or DIY project should only be done if you are sure you can take on the task. Having to pay someone to come out later to finish the job you started or correct any mistakes you made may end up as pricy if not more so then hiring a pro in the first place.