Build a Retaining Wall in Your Yard

By Murray Anderson

A long sloping backyard looks pretty, but the unfortunate reality is that often because of that good looking slope, you just can't do much with your yard. Pools, patios, garden sheds, and even kids' play areas require level ground. A solution to your sloping yard problem might be a retaining wall. A good looking retaining wall can turn your unusable back yard into a safe, level area that you can actually use.

Retaining walls can be made from all kinds of materials - old railway ties, wood, natural stone, and concrete are just a few of the options. However, for the do-it-yourselfer, pre-cast concrete "stones" are a great option. These "stones" are made with a lip on the backside of them so they interlock with blocks laid on top of them, and as a result, don't require any mortar to hold them together. The interlocking bricks produce a solid wall that resists any pressure from the dirt behind them and gives the wall and attractive "stepped back" appearance. An added advantage is the stones are often cast with a taper from the front to the back, so building curved walls is much easier than when working with straight materials.

The main drawback to the pre-cast stones is they shouldn't be used in applications where the wall height is more than 3 feet. So, if your yard slopes less than 3 feet, the mortarless pre-cast retaining wall provides a very viable solution. Even if your yard slopes more than 3 feet, you could still use the mortarless stones to build a series of retaining walls, with no one being more than 3 feet high. In effect, you would create a series of level terraces in your yard.

However, keep in mind that even using the pre-cast stones, building a retaining wall is hard physical work - you'll need to do some digging and the stones are heavy - but it's well within the skill set of a DIY'er.

Here's what you'll need:

Shovel and digging tools
Tape measure
Wooden stakes and string (or a garden hose)
Level
Wheelbarrow
Soil tamper
Gravel
Interlocking landscaping stones
Landscaping fabric
Work gloves and safety glasses

Getting Ready

Figure out where you want to put the retaining wall and mark its shape using wooden stakes and string, or even a garden hose. Use spray paint or flour to mark the outline.

Since the stones are available in different sizes, you'll need to pick out the stones you want before you can calculate exactly how many your wall will require. Before you do any digging, check your local building codes to determine if your need a permit for your retaining wall. Also, have your local utilities mark where their lines are running in your yard.

Excavation

Start by digging a trench a little wider than the width of the stones and about 6 inches deep (you want the first course to be below ground level). Level the bottom of the trench as best you can, then add a layer of sand or stone dust. Level and tamp down the bottom of the trench.

Building the Wall

1. Lay the fist stone in the trench and ensure that it's level, both side to side and front and back. Use a hammer to set it level if it needs adjusting. Continue laying the starter course, checking that each stone is level and adjusting where necessary.

2. Cut one block in half to be used as the first block for the starter course and interlock it with the stone at one end of the foundation course. You cut the stone because you want the seams of the wall to be offset - you'll need to cut a stone for the start of every other course. Cut a stone by scoring it on all four sides with a stone chisel and a small sledge, then put the chisel on the scored line and strike it sharply. The stone should break along the scored line.

3. Go the other end and place a stone on the foundation layer. Run a string between the two stones and check for level using your string level. If your first course is level, these stones should be level. If they're not, adjust the first course.

4. Lay the second course interlocking the stones with the first course, using the string as your guide for level.

5. Backfill the trench with some of the dirt you excavated earlier and tamp it down well to ensure the foundation of the wall is solid.

6. Continue laying the rows of stones, being sure to interlock them and using a half stone to begin each second course.

7. When you've reached the planned height, lay landscaping fabric in behind the wall and up the hill a few feet. This will stop any soil from working its way through the wall. Backfill behind the wall and tamp the soil in place. Finally, add topsoil to the areas you excavated and grade it level.

All that's left is to add some plantings and figure out how you're going to enjoy your newly leveled yard.