Building a Timber Retaining Wall
Good drainage and a stout connection to the hillside are keys to a long-lasting wall.
Synopsis: A generously illustrated guide to building a retaining wall from heavy wood timbers, including construction and drainage details that make a wall durable.
Building durable retaining walls of 6×6 pressure-treated timbers isn’t complicated. If you built with Lincoln Logs as a kid, you know the basics. Remember that the earth held back by retaining walls is incredibly heavy. Wooden walls rely on timber tiebacks and cross ties buried in the earth behind to resist the force exerted by the backfill.
To a degree, dry soil is self-supporting. The real test begins when water saturates the soil, making it semiliquid and less able to support itself. Freezing temperatures make the problem worse. Wet soil expands as it freezes, exerting greater pressure. Drainage is critical.
Retaining walls create terraces, and the size of the terrace is the first design decision you make. A large terrace may involve importing fill, lots of…