Gravity-Stack Concrete Retaining Walls

Retaining Walls - Gravity-Stack Concrete

Relatively new on the scene, gravity-stack concrete modules can make a durable retaining wall. In place of the traditional mortar and rebar, they lock together with pins, lips or by their weight and shape. They're faster to install than standard concrete blocks.
The modules come in different sizes. The largest that are practical for a homeowner weigh about 90 pounds.

Step by Step: A Gravity-Stack Retaining Wall

This 3-foot-high wall uses one of several brands of gravity-stack modules. Each brand looks somewhat different, but building steps are similar for all.

1. Mark-off the wall line and dig a trench the width of a block and 8 inches deep (or the depth specified by the manufacturer). Level the bottom with compacted gravel.

2. Set-in the bottom layer of blocks, checking that each is level in both directions.

3. Stack each successive layer (for a total of 6), making sure to stagger the vertical joints. Design of modules establishes the proper setback.

4. Glue precast cap modules to the top of the wall, according to the manufacturer's instructions.

5. Add drainage line and backfill.

Safety

Lifting concrete blocks or modules is tough on backs, arms and hands. Have strong helpers transport the materials to your site. Work slowly, wearing leather workgloves.

Safety-related resources on the Web:
Index of Occupational Safety and Health Resources (http://turva.me.tut.fi/~oshweb/)
National Safety Council (http://www.national-safety-council.ie/)
National Institute for Occupational Safety and Health (http://www.cdc.gov/niosh/homepage.html)
Other safety Web sites

Tools

4-foot mason's level
mason's line
shovel
wheelbarrow

Tool and hardware-related resources on the Web