How to Lay Cement Block for a Basement Retaining Wall

Dig a trench 2 feet wide and 4 inches deep along the area for the retaining wall. Smooth the dug-out area flat with a trowel or the back of a shovel. The trench should be the length of the intended wall.

Lay compacted class V base material in the trench. Base material is available where concrete materials are sold. Select base material that is 2 feet wide and 4 inches thick to fit the length of the trench. Push evenly into the trench with a tamper tool. Tampers may be rented from concrete or building outlets.

Pour a 2-inch-thick layer of clean-fill or construction sand over the top of the compacted base material. Smooth the sand with a hand trowel until it is completely level and compacted slightly. The dug-out trench should now be level with the ground.

Measure out 2 feet from the natural soil wall and set the first block. Start on the left of the intended wall area, at the corner of the sand. The slit should be against the natural soil wall. Use a level to ensure the block is flat. Align the next block flush to the first and again use the level to ensure it is flat. Continue in this manner along the entire filled trench.

Hammer in reinforcement pins. Along the tops of the blocks, pound in reinforcement pins in the cut slots. Slightly countersink the pins so they won't interfere with the next layer of blocks.

Score and cut the half-block for the next row. Use a hammer and chisel to cut the block directly in half. If ordering blocks from a distributor, request they be cut prior to delivery.

Apply a layer of concrete adhesive to the top of the first row, using a paintbrush, and begin setting the second row. Offset from the front approximately a quarter-inch. Begin with the cut half-block. Continue applying bricks to form the second tier of blocks, using full-size blocks until the end. Place the second half of the cut block at the opposite end. Offset each additional row in the same manner. Begin and end every other row with a half-block.

Fill the space behind the block wall with gravel. Shovel in the gravel and pack with a shovel until the gravel is level with the top of the wall.

Apply a concrete cap. Use 3-by-12-inch blocks to create a cap to cover the width of the top of the created wall. Apply a thick layer of concrete adhesive to adhere the cap properly to the last level of wall blocks.

Apply a thick layer of concrete to the front of the wall. Mix general purpose concrete according to the manufacturer's directions in a large bucket or wheelbarrow. Apply it smoothly to the wall with a trowel, filling in the quarter-inch differences in the layers. Allow it to dry for at least 24 hours.