The Tandem Wall retaining wall system can be used to build curved or straight retaining and freestanding walls in a range of residential and light commercial settings, according to the manufacturer. The blocks, which are available in two dozen different textures, are assembled in pairs joined by polypropylene connectors. The space between the two parallel faces is filled with crushed stone. Walls of up to 3 feet can be built without geo-grid reinforcement, and up to 8 feet high with reinforcement. In addition to Tandem Wall, the company also makes a Mega-Tandem segmental retailing wall units, Tandem Modular Grid for facing a porch or deck, and a Tandem Column Kit.

Belgard, 877/235-4273,