How to Build a Retaining Wall

Building a retaining wall

In these videos, we will learn how to build a retaining wall.

A retaining wall allows you to contain a patch of earth on a small surface, in order to meet various needs. In this video we will learn the different rules and stages to follow in order to build this type of wall.

In this example, we are going to build a low wall of 60 centimetres in height (24") to create an area suitable for a vegetable garden.

We will start by determining the minimum required height of the retaining wall. Then we will mark out the area, dig it out, and finally lay down the foundations. Next, we will start building the wall; set up the drain system and finish by covering it with soil.

In order to determine the miminum height of the wall, we need to calculate the distance separating the highest point of soil from the lowest point which will be at the foot of the future wall.

Place a peg at the highest point of the soil, and a second where you want to build your wall.

Tie a piece of rope between the two.

Place a spirit level on the rope to ensure the line is horizontal.

Measure the distance between the ground and the rope.

You will find the minimum height of the wall by dividing the ground-rope distance in half. For example, if the distance is 70 centimetres, the wall will have to be at least 35 centimetres high.

Once you know how high the wall needs to be, it's time to start thinking about the foundations.

The goal of building a retaining wall is to contain the soil. There will always be a lateral force pushing against it, strong foundations are necessary for the structure to hold.

If concrete bricks are used to build the wall, add vertical rebars that will reinforce it. These aren't necessary for stone or brick structures.

To learn how to lay foundations, watch the video 'Retaining wall: foundations'.

For now, let's look at building the retaining wall.

The wall can be built using bricks, dry stones or breeze-blocks, ideally using local resources.

Watch the tutorial 'building a wall with grindstones' to continue your structure using this particular material, or view 'building a retaining wall with concrete aggregate'.

Once the wall is built, we will lay a geo-textile cover, a bed of gravel and a drain. This drain system will protect the structure from stagnant water.

Watch the complementary video "Retaining Wall: drainage installation".

Once the drain is built, let the wall dry for a few days.

The only things left to do are filling up with soil and making sure that it is well leveled.