How to Build a Retaining Wall

A sloping landscape is a pleasure to the eyes, but it limits what you can do in your yard. You need level ground to hold a party. It is dangerous for your kids to play on sloping ground. It also exposes your land to erosion.

You can build a retaining wall on your sloping yard. It will require hard work, but it is easy enough to do by yourself.

You will need the following materials and equipment for digging and backfilling:

  • Interlocking concrete blocks
  • Shovel and digging tools
  • Tape measure
  • Wooden stakes and string
  • 4” PVC drain pipe
  • Level
  • Wheelbarrow
  • Soil tamper
  • Gravel
  • Landscaping fabric
  • Work gloves and safety glasses

There are different materials that can be used for constructing the retaining wall. The most common are: timber, interlocking blocks, stacked stone, brick or block, or concrete. For beginners in construction, the recommended material is interlocking concrete blocks which are easy to assemble.

Steps to Build a Retaining Wall

  1. Determine the area where you need to build. Check the spots where water runoff is causing the soil to slide, or where a downhill spot is losing soil support. Mark the areas with stakes and string.
  2. Digging. Before you dig, you should know the frost depth and the type of soil. Most retaining walls fail because of frost heaving and poor drainage which causes saturated soil.
  3. Concrete walls need foundations below the frost line. For non-mortared walls, you should build a trench at the level below frost line, and fill it with gravel. If you live in a non-freezing region and your soil drainage is good, you can just dig the topsoil to serve as foundation. Where you may have problems with drainage, it is best to install a drain pipe.
  4. After you have done all these, then you can start backfilling. Lay down landscape fabric before adding new gravel to replace the original soil. Use gravel which is no smaller than 3/4 inch in diameter. Shovel a four-inch layer of gravel. This should slope one inch for every four feet. Then lay your four-inch PVC drain pipe.
  5. Start laying the interlocking blocks, placing them evenly. Cut a block in half to be used for interlocking at the end of the first tier. Then lay the second tier. You can run a string between two blocks to check if they are level.
  6. Continue laying the blocks. Shovel in the backfill as you build the wall, one tier at a time. Make sure that you interlock them and use a half stone for the start of each tier.
  7. When you have reached the desired height, finish the backfilling. Tamp the soil in place and put landscaping fabric behind the wall. Since retaining walls will hold a lot of pressure, the ideal height is only between three to four feet.
  8. You can now add topsoil and plant grass or other plants on your leveled yard.