Base Course Installation for Segmental Retaining Wall

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By Joseph Kowalski
Sep 25, 2008 - 3:47:27 PM

The first row of blocks for a segmental retaining wall is called the base course.  The base course bears on the top of the stone leveling pad.  Tools required include: tape measure, gloves, torpedo level, 2-foot level, sledge hammer, rubber mallot, scrap 2x4 wood, shovel and gloves.   

It is important that the base course be installed perfectly level.  Each block must be level front-to-rear and side-to-side.  Also, adjacent retaining wall blocks must be at the same elevation; otherwise, the next block on top will rock back and forth.  Ultimately, this “rocking” block will crack because its weight is not evenly distributed equally on the blocks below.   

To properly install the base course on a compacted leveling pad follow this procedure:


§          Place block at correct location for required geogrid length;

§          Level block in all directions using small torpedo level;

§          Use rubber mallot to adjust level;

§          If additional force is needed to hammer block, use sledge hammer, but be sure to protect block with scrap wood;

§          Install block adjacent block and level the same way.  Make sure that adjacent blocks are at the exact same height; and,

§          Periodically check the wall for level over longer distances using your laser level.