If you are planning to build retaining walls on your property, here are the steps that you need to undertake.
Step 1: Preparing your tools and materials
For retaining walls, you will need to have a granulated drainage material, about 12 to 20mm, and an agricultural drainage pipe, about 90mm in diameter, to facilitate free draining. You will also need course sand which you will use as a levelling pad, a road base, a spirit gauge, a wheelbarrow, a lump or rubber mallet, string line and pegs and a garden room. Depending on the type of retaining wall you are building, you might also need masonry cutting tools.
Remember that if you are undertaking any type of work inside or outside your home, safety is essential. Be sure to wear the appropriate safety gear like safety glasses, protective gloves and ear protection.
Step 2: Site preparation and planning
Once you have gathered all the tools and materials that you will need for building retaining walls on your property, the next step that you need to undertake is to prepare the site where you plan to build your walls.
To do this, you need to locate the actual area where the walls will be placed and mark this location either by using stakes and a string line or spray painting marks directly onto the ground.
After this, you can begin digging a shallow trench, about 180mm deep and 350mm wide. Next, fill the trench with either a road base or crushed rock. Using a deep levelling pad, compact the road base or crushed rock until you have a levelling pad 100mm deep.
After compacting the crushed rock or road base, the next step you need to do is to create a bedding layer using course sand. Spread about 25mm of course sand over the trench and make sure it is level.
Step 3: The first course
Once you have prepared the area where the retaining walls will be placed, you can now commence with the actual building.
Start by placing the blocks for the retaining wall side by side. Make sure to check the alignment of the blocks by using a string line. Make sure that as you put one block to the side and front of another block, you check for alignment using a spirit level. Take your time and do not rush through the process. Remember, the first course should be level; otherwise, this would affect the additional courses that you will add.
After laying down the first course, the next order of business is laying down the drainage materials. First, install the agricultural pipe at the back of the wall and surround this with a granulated drainage material. Next, backfill the drainage layer. Under no circumstance should you use clay as the agricultural pipe will fall and escape.
Step 4: Laying the additional courses
Before laying the additional courses, make sure that the initial layer is free from excess drainage materials.
After this, proceed to laying the next course in a running bond pattern halfway across the initial course. Next, place the drainage material and backfill. Make sure to compact these. Continue stacking the units, drainage material and compact backfill until you reach the desired wall height. Once you have achieved your desired wall height, place a line of adhesive at the rear and the front and then place the capping unit.