Instructions On How To Build A Retaining Block Garden Wall
Instructions on how to build a retaining block wall are important for the do-it-yourselfer, because if done incorrectly, it can result in a breached wall. Retaining walls are designed to hold back the slope of a hill when the pitch of the slope is changed, or to retain soil in a garden or around the roots of a tree. The project will require some physical work, including heavy lifting and shoveling.
To build a retaining block wall you will need:
- Tape measure
- Decorative block
- Gravel (or crushed rock)
- Tamper (soil compactor)
- Landscaping fabric
- Brick chisel or circular saw with a concrete blade
- Measure the length where you want to build your retaining block garden wall.
- Visit your local materials supplier and choose the type of retaining block you want for your project. Block comes in different types, colors, sizes and shapes (rounded, angled, flat faced, etc.). Keep your budget in mind as you also consider the price of the retaining blocks. Some types of block will also have available cap blocks that are used along the top row of the retaining block wall to give it a special finished appearance.
- Measure the height of your desired retaining block garden wall.
- Calculate the number of retaining blocks you’ll need by dividing the length of the wall by the width of one block. This will give you the number of blocks you need for one course (one row). Divide the height of the wall by the height of one block. This will yield the number of courses you’ll need. Multiply the number of courses by the number of retaining blocks in one row to arrive at the total number of blocks required for the project.
- Prepare the base upon which to build your retaining block garden wall. Dig an area about eight inches deep by the depth of one block. Excavate this area for the length of the wall.
- Fill this trench with gravel, crushed rock or stone, and pack it down. You may want to rent a tamper from your local equipment supply store.
- Lay out your first course of block along the foundation you have prepared.
- Stack retaining blocks to form the second row, but stagger them so that you start with one-half of a block.
- Continue to add courses until you reach the desired height, off-setting the blocks on each row from the row underneath.
- Cut a piece of landscaping fabric and place it against the backside of the wall. This will ensure that no soil sifts through cracks between the blocks caused by erosion. This also prevents the growth of weeds through the garden wall.
- Backfill soil up against the fabric and the retaining wall.
If you plan to build a very high wall, one that is over three-feet tall, it is advisable to consult with a professional. A wall can have several tons of pressure on it from the soil behind it, and special engineering, along with drainage considerations, must be taken into account.