Retaining Walls Using Concrete Block Wall Systems

 4’ High and Under

Before building a retaining wall there are a few matters that need to be determined.

Measure the length and height of the wall to arrive at the square feet of face to determine how much material will be required.

Choose the most appropriate material for your wall, considering wall dimensions and elevations, appropriate base and backfill material for your soil conditions and whether or not you need an engineered design (usually for walls over 4’ tall). Check with the local building department to see if a building permit is required.

 Construction

• Dig a trench 14” wide, deep enough to accommodate 1 course of block and 6” of compacted base material
• Compact in 2” lifts with plate compactor
•  String line the back of the wall to maintain a straight wall
• Place bottom layer of concrete block units, leveling each from side to side as well as front to back. Backfill with base material. (Remember to start at the lowest point of the wall)
• Position the following courses on the proceeding layer, staggering the joints. Most block systems have an automatic setback in their design. It is extremely important to backfill each course.
• Place a drain tube behind the wall at grade to enable moisture to drain and minimize hydrostatic pressure behind the wall. Backfill with clean, free-draining aggregate 12” behind the wall. Fill all voids, both cores and spaces between units.
• Fill any remaining area between the aggregate backfill and the embankment with native soil. Compact this material also.

Tips

For walls taller than 4' consult with a qualified expert, preferably an engineer.

Be sure to keep your wall straight with the string along the back edges of the blocks (the fronts are split faced and are all different from one another).

To get perspective, check from a distance for straight and level courses.

Aggregate backfill should be to the height of the bottom of the top course of block.