- 1). Contact your local utility company to have utility lines marked in the area where you'll be constructing the cinder block wall.
- 2). Dig out grass and dirt with a shovel in the area where you will be building the wall. Create a level trench 6 inches deep and about 2 feet wide. Level the area with a hoe. Clear a 1-foot area for crushed rock behind where the wall will sit.
- 3). Pour 4 to 6 inches of base material like pea gravel into the trench and compact it with a hand or power tamper. Pour masonry sand over the pea gravel and use a straight screed board to level the sand.
- 4). Place the first layer of cinder blocks on top of the sand. Place a level across the top of each block to make sure it is level. If you need to heighten a block, back more sand underneath it; or to lower it, take some away. Pack soil from the area where you're working around the first row of the wall of cinder blocks to stabilize them.
- 5). Moisten the blocks with water and spread a layer of mortar on the top of each block with the trowel and stack the next row of cinder blocks on top, making sure each row is even using the level. Blocks should be stacked on top of each other so the first block in the second row is centered over the first two blocks in the first row. The third row follows this pattern and so forth. The blocks should be level if the first row was, but you may need to chisel a bit off the bottom of a block to shorten it or add a bit more mortar to heighten it. And tamp each block into position with the mallet before the mortar sets.
- 6). Insert bent anchor bolts (vertical bars with a bend at the top) in the holes on the blocks approximately 2 inches away from the inside face of the cinder block wall every 2 feet on center. These bars will help strengthen the wall and will stay in place when you pour the concrete mix into the holes of the blocks when the wall is built. Cut the blocks to size with the chisel and mallet as necessary as you lay them. Continue layering rows of cinder block, mortar and anchoring bolts.
- 7). Backfill behind the cinderblock layers with crushed gravel using a shovel when you complete the wall. Pour wheelbarrows full of gravel behind the wall out to the 12 inches you left when you dug the 6 inch trench. Fill this space with the gravel. This will allow for water drainage.
- 8). Fill the holes in the cinder blocks with a mix of concrete and pea gravel. Smooth the concrete with a trowel.
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