Retaining walls allow for the expansion of usable space, provide support for structures, and can add aesthetic qualities to a landscape. Premature failure of retaining walls is common across the United States, but a properly constructed retaining wall can add significant value to a property and should last for decades.

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Below are common items to consider and issues to be familiar with.

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• Reasons for a retaining wall

  • ​More functional space. A retaining wall can create or expand a patio, yard, or other space and change a sloped lot into a flat, usable area​

  • Building or parking lot support

  • Erosion control

  • Seating

• Retaining wall design options (listed from "typically" least expensive to most expensive)

  • Timber walls (railroad ties or other wood)

    • Moisture sensitive​

    • Limited lifespan

  • Interlocking blocks (stacked walls)

    • Many types, sizes, shapes, and aesthetics available​

    • Typically masonry construction

    • Some block walls require a cap

    • Geotextile mesh (Geogrid) must be used in many situations

    • Some block walls need to be filled with aggregate

  • Brick​

    • Typically small planter walls​

  • Gabion Wall​

    • Welded wire cage filled with stone​

    • No footing needed

    • Many times used for erosion control situations

  • CMU (Concrete Block)​

    • May be filled or unfilled​

    • Mortar required to build a block wall

    • May be reinforced with rebar

    • Typically require a footing to be poured before the wall is constructed

    • Careful attention needed for weep hole placement​

    • Typically are finished with a facing for aesthetics

      • Stucco​​

      • Thin Brick

      • Stacked stone or flagstone

  • Poured concrete wall​

    • An infinite number of shapes and designs

    • Always reinforced

    • Require a footing to be poured before the wall is constructed

    • May be finished with a facing or painted

    • Careful attention needed for weep hole placement​

  • Natural stone wall

    • ​Natural look

    • Widely considered the most attractive

• ​​Common issues and causes of premature failure

  • Poor drainage

    • Many walls fail due to improper drainage - water can develop hydrostatic pressure on the wall. Freeze/thaw cycles​ can cause a wall to fail prematurely without proper drainage through the wall.

  • Improper use of filter fabric. 
    • Filter fabric should typically not be used directly on the back of the wall.​ Filter fabric tends to get clogged with sediment leading to additional pressure on the wall.
  • Not including drainage aggregate on the back of the wall
  • Not installing Geotextile mesh (Geogrid) on stacked walls (typically needed every 2nd course)

  • Block used for wall is too small

  • Foundation issues (insufficient compaction, footing construction, etc.)

  • Unanticipated loads (equipment, vehicles, etc.)

  • Lack of steel reinforcement

  • Not filling block with aggregate (required in some stacked walls), or mortar/grout (CMU walls)

  • Rot (timber walls)

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