Build a Retaining Wall in Your Yard

Lead Image
What You'll Need
Tape measure
Soil tamper
Landscaping stones and fabric
Work gloves
Safety glasses

A long sloping backyard looks pretty, but the unfortunate reality is that those pretty sloping backyard hills are all flash and no substance.

Almost anything that makes having a backyard fun - pools, patios, garden sheds, kids' play areas - all require level ground. A solution to your sloping yard problem might be a retaining wall. A nicely constructed 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.

Pre-Cast Concrete

pre-cast stones with interlocking lips on the back

One great option for retaining walls specifically is pre-cast concrete "stones.” These stones are made with a lip on the backside of them so that they interlock with blocks laid on top of them, and as a result, they 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 a unique look. An added advantage is the stones are often cast with a taper from the front to the back, so building a curved wall, which is the shape many retaining walls take, 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 a wall is greater than 3 feet tall. So, if your yard slopes less than 3 feet, the mortarless pre-cast retaining wall provides a viable solution. Even if your yard slopes at a greater height, you could still use the mortarless stones to build a series of retaining walls so long as no individual wall exceeded the 3-foot height limit. In effect, you would create a series of level terraces in your yard.

While the pre-cast concrete can make the job easier under the right circumstances, the overall process of installing a retaining wall is still quite labor intensive. Even if you’re not laying any mortar, you’re going to be doing some digging and heavy lifting. So, prepare yourself.

Step 1 – Planning

Figure out where you want to put the retaining wall and mark its shape using wooden stakes and string. 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.

Step 2 – Dig the Trench

Start by digging a trench a little wider than the width of the stones and about 6 inches deep. You’ll actually want the first row of blocks 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 the added sand by tamping down the bottom of the trench.

Step 3 – First Layer of Stones

Lay the first stone in the trench and make sure 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.

Step 4 – Cut a Block For Your Starter Course

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.

Step 5 – Verify Level

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.

Step 6 – Lay Second Course

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

Step 7 - Backfill

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.

Step 8 – Interlock and Lay Additional Rows

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

Step 9 – Fabric Soil Shield

Once you've reached your intended height, lay landscaping fabric in behind the wall, extending the fabric so that it continues a few feet up the rest of the hill. This will stop any soil from working its way through the wall.

Step 10 – Restore Soil

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 figure out how you're going to enjoy your newly leveled yard. A terrace garden is a great way to take advantage of the newly leveled soil behind your wall.

About the Author

Murray Anderson is an experienced freelance writer with articles published in both the United States and Canada. He has written on a wide range of topics, but specializes in home maintenance and how to's.