Concrete block retaining walls can provide additional strength to a backyard's foundation with elevated slopes by preventing soil erosion. They can eliminate extensive masonry work, can last longer than lumber walls and are cheaper than poured concrete or rocks. Oftentimes, an installer may encounter some obstacles along the way. One of the obstacles is trying to install the retaining wall on curved areas.
Remove the debris, such as dead roots and weeds, at the base of the location where you will put your retaining wall.
Measure the retaining wall's layout. Mark out the areas using strings and stakes.
Dig a trench about 6 inches deep. The width and depth of the trench should accommodate the size of the concrete retaining wall blocks that you are using.
Fill the base with rocks; spread them evenly. Use gravel, crushed rocks or road base. You can use one type or a mixture of rocks compacted together. These rocks will support the first layer of blocks. Tamp the base with a hand tamper; use a motorised tamper for bigger projects.
Check that the compacted rocks are even and levelled. For sloped areas, build a trench at different levels.
Lay down the first layer of blocks on top of the base rocks. Place the blocks next to each other. Check the alignment and level of each block. Use a mallet to align the blocks. Use the string line as a guide.
Adjust the string line along the curved areas. Use the curved string as your guide.
Cut the blocks and half nuts using a masonry saw for sharp curves. Use a ruler to mark the angle to form the curve before cutting. For smaller cuts, use a chisel to achieve the curved angle.
Fill the gaps in between the blocks with gravel. Doing so will strengthen the foundation and provide drainage at the same time. Use a broom or brush to push the excess gravel inside the gaps and voids.
Lay down the second layer of blocks. Check alignment, and level using the same technique when laying down the first layer of blocks.
Place a reinforcement grid along the curved walls. Make sure that the grid follows the back of the blocks. Use a utility knife to make a slit; extend the slits outward by overlapping the edges to follow the curve.
Lay down the succeeding rows of blocks until you reach the desired height. Check alignment and level each time. Place the caps on top of the last row of blocks.
A standard retaining wall is up to 4 feet high; you may need a permit for higher retaining walls.
Wear eye protection and work gloves when handling the saw and other motorised equipment to avoid injuries.