A Concrete Retaining Wall Forming Method in a Radius

Retaining Wall Basics

• Building a retaining wall begins with digging a trench. Dig this trench with shovels and install a layer of gravel at least 4-inches thick on the bottom of the trench. The loose composition of gravel allows water to seep through to soil below the retaining wall, preventing sitting water around the base of the walls. Always use concrete blocks when constructing a curved retaining wall, building the blocks in layers from the ground up. Always complete an entire layer before adding the next one on top. Use a level to determine the flatness of each layer.

Radius and Materials

• When a retaining wall curves, the curve must sit on an exact radius to ensure structural stability for the wall. A radius describes the distance between the center of a circle and any point along its circumference. The radius of the bottom-most layer of a retaining wall depends completely on the materials used; every manufacturer of retaining wall blocks provides different radius requirements. For instance, Allan Block block manufacturers recommends a radius of 5.25 feet when using AB stones to build a 3-foot-tall wall. This radius raises to 5.5 feet when building a 4-foot-tall wall. Always check manufacturer information before laying out a retaining wall.

Radius and Layers

• A stone retaining wall requires a slight backward angle in order to work properly. When you build a retaining wall, you must place the second layer of blocks slightly back from the edge of the first layer of blocks and so on with each subsequent layer. A wall built at an angle pushes the pressure placed on the wall from behind to the bottom of the wall, where it exerts the least amount of damaging effect on the wall. Because of this rule, the radius of each subsequent layer of stones on a retaining wall curve exhibits a slightly smaller radius than the previous layer. The radius of the top layer should measure at least the same as the height of the wall.

Radius and Formation

• Upon determining the ideal radius for the wall, place a row of stones on the ground to create a mockup of the wall before beginning construction. Stop this wall at the point at which you intend to begin curving blocks. Measure the distance of the radius straight back from this point and place a stake in the ground at the full length of the radius. Tie a string the same length of the radius to this stake. By sweeping this string in a semi-circular movement, you can determine where you need to place each block to create your curve. Proceed with building the wall with the stake and string intact, using the manufacturer's installation manual as a guideline.