How To Build A Retaining Wall
Retaining walls can add attraction to a landscape, increase the value of your property and retain sloped areas to create user friendly, level ground.
There are lots of different retaining wall materials out there. It all depends on how much you need to retain on what material you can use.
We generally use concrete blocks, this means it can be faced/cladded in any style you desire.
What do I need to build my wall?
To get started, the tools you’ll need are a shovel, string line, hammer and bolster or a power cutting tool, a trowel, spirit levels, cement mixer, lump hammer, hose pipe with water supply, a pointing trowel and a pointing iron.
Now the materials, you’re going to need all in 20mm to dust aggregate, coarse sand and cement for the wall footing. For the block work, you will need fine sand, cement and blocks.
If you’re not sure of how much of each material you need, head over to our online calculators to help.
Once you have all of this in place, you’re ready to get building!
Our step by step guide
Firstly you need to dig a trench for the footing of your retaining wall. Generally, the footing should be about 2 times wider than the base of the wall.
To create the footing you need to mix the all in 20mm to dust aggregate, coarse sand and cement with water and place this into your trench. It needs to be level all the way across and should be 300mm in depth.
Once done, leave to cure.
With a retaining wall, it’s always best to lay your blocks on the flat side rather than upright, as this gives it extra strength.
Mix up some mortar using the fine sand and cement and spread a thin layer on top of the concrete footing. Then, start laying your blocks so that they are about 15mm apart, in a straight line and level. It’s best to use a string line to create a straight line on top of the footing for you to follow.
Once you have your first course of blocks laid, go back and fill in the joints between the blocks with the mortar. When filling the joints make sure that the mortar is packed tightly and up to the top of the blocks. This makes sure that all the blocks are bonded together correctly.
Now you can carry on and lay the next course of blocks.
When placing the second course of blocks on top of the first, place them so that they overlap the joints on the first course. Make sure that the edges of the blocks are aligned with the first before setting them into the mortar. The easiest way to do this is to place a level on the front of both courses and move the top block until they’re level.
Then, just as you did with the first course, go back and fill the joints between the blocks with mortar.
Time to cap the wall!
We generally use coping stones or cut to size paving slabs if matching in with its surrounding landscaping.
This is done the same way as laying the blocks. Put the mortar on top of the last course of blocks and then place the capping on top making sure it is level.
Now your wall is built, you will need to go back around and smooth off all of the muck joints and remove any excess mortar.
Use the pointing iron to gently run over the joints to give the mortar a nice smooth, even finish. Now remove any spilt mortar, do this by scraping the blocks with the trowel or a wire brush if you have one handy. This will leave the wall looking nice and tidy.