How To Build A Retaining Wall

Retaining Wall

Learning How To Build A Retaining Wall is a great home-improvement project that can be completed in a weekend. Whether you’re a novice or avid DIYer, the following blog includes tips and tricks along with professional guidance that will help you build your own retaining wall. 

Structural Considerations When Building A Retaining Wall

Unlike any other landscape walls, retaining walls have structural requirements. Simple garden walls aim to provide privacy, mark property lines, or beautify a property. The purpose of a retaining wall is to hold back the earth itself, which can exert thousands of pounds of force. For this reason, it’s best to build your retaining wall out of materials such as wood timbers, bricks, concrete blocks, or even natural boulders.  

For DIYers, concrete blocks are the best and easiest to build with. Furthermore, concrete retaining wall blocks are shaped in a way that creates a natural setback. This design causes the wall to be angled slightly back into the slope, improving its holding power. 

Supplies You Will Need From Your Local JJ Kennedy Store

Tools

  • Chisel & Rubber Mallet OR a Circular Saw
  • Level
  • Tape Measure
  • Rubber Mallet
  • Broom
  • Tamper
  • Shovel 
  • Rake
  • Caulk gun

Materials

  • Corrugated pipe
  • Gravel
  • Construction Adhesive 
  • Wall Blocks
  • Capstone

The Process Of Building A Retaining Wall

Step 1: Excavate your space.

  • Before you start stacking, you’ll have to start digging. The amount of ground you’ll have to move depends on the size of the blocks you’ll be using. It’s recommended that you dig your trench to the depth needed and 6 inches wider than the size of the block you’re going to set. 

Step 2: Tamp the soil and lay down gravel.

  • Using a tamper, pack down the bottom of your trench. Then, add about 2 to 3 inches of gravel to the bottom of the trench. Due to soil erosion, your retaining wall should be built on a solid foundation made from gravel. It’s best to choose gravel that has stones sized between ½-inch and ¾-inch. Rake the gravel once it’s been laid, then go over the gravel with a level. This ensures that the trench area is uniform in height. Tamp the trench again, compacting the base one final time. 

Step 3: Lay the first course.

  • Beginning at one end, set the first block into the base layer of gravel and press down firmly. Use a level to check that the first block is level in all directions (i.e. from side to side AND from front to back.) Lay down the next adjoining block, and once again use a level to make sure it’s level and aligned. 
  • Continue this process with subsequent blocks to complete the first course of the wall. Once the first course is complete, fill the space between your retaining wall and landscape with gravel. Tamp the gravel to increase stability and durability. 

Step 4: Install subsequent courses.

  • By installing a stable and even first course, you’ve set yourself up for success. Now all that is left is to build upwards, so here’s how to do it.
  • Brush off the first course of blocks with a broom to remove debris. Start the second course with one half of an end block. Blocks should be staggered, so you’ll need to cut the end blocks of each even-numbered course in half. For example, the second and fourth courses should have half end blocks, while the first and third courses have full end blocks. 
  • To make cutting your blocks easier, some have V-shaped notches on the backside. These allow you to easily break the block in half using a mallet and chisel. If your chosen block doesn’t have these notches, cut blocks in half by using a circular saw with a masonry blade. 
  • Once the first half end block is laid, continue with the rest of the second course blocks and finish the course off with the other half of your cut block. 

Step 5: Install a drainpipe (optional but recommended).

  • If you get heavy rains, installing a drainage pipe behind the wall is highly recommended. Doing so is easiest when you’ve only installed one or two courses. The perforated corrugated pipe should run behind the entire length of the wall at a grade. This ensures the water drains correctly and can flow away from the area. 
  • Once the pipe is in place, pour gravel behind the wall to completely cover the pipe. Then resume laying courses until your desired height is reached. 

Step 6: Cap off the retaining wall.

  • Putting down a layer of capstone completes your retaining wall and enhances the overall aesthetic. To place capstone securely brush off the last layer of stones to clear them of any debris and ensure they are completely dry. Using a caulking gun, apply a generous amount of construction adhesive to the top layer of your retaining wall. Then, place your capstone; they should overhang the retaining blocks by 1 to 1 ½ inches. 

Get Started on your DIY Concrete Project Now!

A retaining wall is a functional and attractive addition to your home’s landscaping. Learning how to build one yourself is a great way to save you some money but could quickly become a lot to handle. Stacking retaining wall blocks is easy. However, keeping them stacked for years is difficult–but not for JJ Kennedy. If you want a retaining wall that can last for decades, contact us today. You’ll be glad you did!

You can also visit us at any one of our 8 locations for Ready-Mix Concrete, Builders Supplies, Block & Material Delivery, Keystone Retaining Walls, and more: Clarion, Clarks Mills, Imperial, Indiana, Kittanning, Punxsutawney, Ridgeway, Zelienople

We have been providing concrete in Pennsylvania, Ohio, and West Virginia since 1905 with the highest standards of concrete quality assurance.

Request a Quote Our History > Call Us Today: 866-699-3835