A retaining wall is a structure that is used to hold or retain the soil behind it. Many different types of materials can be used to build a retaining wall such as concrete blocks, treated timbers, rocks or poured concrete.
Planning How You'll Build
When choosing which material to use for your retaining wall you must consider:
- What kind of soil is there?
- Is there anything above the wall?
- What will the height of the wall be?
A gravity wall (a wall that can stand by itself) cannot be too tall because it relies on its own weight and setback to hold up the soil behind it.
Typically, a retaining wall that exceeds 3 to 4 feet will need to use geogrid (a synthetic mesh material) to create a reinforced wall that will provide it with stability. There are different types of geogrid that can be used when building a retaining wall since each situation is different.
Steps to Building Your Retaining Wall
I’m going to be using concrete blocks as my example material, but as I mentioned before, there are many materials that can be used.
Carefully dig out the area where you will be placing the first row of blocks. Make it several inches below the ground. If needed, add filler such as gravel, before placing the first layer of block because it’s extremely important that the ground that your base layer is on is both sturdy and level. The rest of the wall depends on it.
Lay blocks down from one end to the other, making sure the blocks line up correctly and are level with each other.3. Continue Stacking
On the second level you should start with a half block. Do this on every other row to stagger the blocks, making your retaining wall more structurally sound.
Some blocks are designed specifically retaining walls and easily interlock with one another, but if this is not the case for you then I suggest using construction glue too.4. Backfill
Add backfilling as you finish each layer. Backfill is the soil material you put right behind your wall. It is important because it creates drainage, prevents weeds and fills any gaps between the layers.
Depending on what is at the top of your retaining wall there are many different finishing options. When using blocks, one of the most popular options is to use capstones. Capstones are similar to the rest of the blocks, but are typically smooth on the top and can give your retaining wall a pleasing finishing touch. Other finishing options include rocks, gardening or mulch.
Other Notable Tips:
- Always plan and design your layout before beginning
- Do your math – determine the length of the wall, how many blocks (or other material) will be used in each row and the height of the wall
- Avoid having your home’s downspouts pointing toward the wall
- Keep the soil bed well below siding if your wall is close to your house
Once your retaining wall is finished, you can enjoy complete your landscaping with fresh flowers and other suitable greenery!