How To Build A Retaining Wall

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WHAT IS A RETAINING WALL?

"Foodscaping" by Scott Costello.  Photo via Flickr.

“Foodscaping” by Scott Costello. Photo via Flickr.

A retaining wall is a structure that holds back soil or water. Retaining walls are built to reduce erosion or to correct an awkwardly sloped landscape retaining walls can be made of stone, concrete block, or wood timbers. Consideration should be given to the height, the type of soil behind the wall, and what will be on top of your retaining wall. Based on these considerations, the appropriate type of retaining wall can be constructed.

  • GRAVITY RETAINING WALL
    The gravity retaining wall is the most commonly built DIY (Do It Yourself) retaining wall. Gravity Retaining Walls have much thicker walls that the other types. The thicker walls and dense materials provide the weight needed to retain the material behind the wall. Instruction on how to build a Gravity Retaining Wall are given below.
  • SHEET PILE RETAINING WALL
    Sheet pile retaining walls are usually used in soft soils and tight spaces. Sheet pile walls are made out of steel, vinyl or wood planks and are driven or buried into the ground.
  • CONCRETE CANTILEVER RETAINING WALL
    Cantilevered retaining walls are made from an internal steel-reinforced, cast-in-place concrete or mortared masonry stem. These walls cantilever loads (like a beam) to a large, structural footing, converting horizontal pressures from behind the wall to vertical pressures on the ground below.
  • ANCHORED RETAINING WALL
    An anchored retaining wall can be constructed in any of the aforementioned styles but also includes additional strength using cables or other stays anchored in the rock or soil behind it. This method is complex and not a good DIY project for the beginner.

By Ingolfson at en.wikipedia (Original text : Uploader.) [Public domain], from Wikimedia Commons

BUILDING A GRAVITY RETAINING WALL WITH STACKABLE CONCRETE BLOCKS

Stackable concrete blocks are generally recommended for walls less than 3’- 4’ high. Taller walls typically need additional structural reinforcement and may require a building permit along with professional advice or help.

  1.  Before starting construction of your retaining wall, make sure that there are no buried pipes or cables below the surface of your soil. Use a garden hose or landscape spray paint to mark out your wall.
  2. Dig a trench along the marked line. Using a Mini-Excavator will make this step a snap! Dig the trench a little bit larger than your concrete block. You want your first course of blocks to be below ground level. This will help make your wall stronger to hold back the earth behind it. Use a level to ensure that the ground is level. Tamp down the earth and add a layer of sharp gravel. Next place your first course of concrete block.
  3. Begin laying your blocks in your trench. Make sure the block is level from front to back and side to side. Adjust by lifting the block and adding more gravel or digging deeper as necessary. Getting the first course level is the key to a successful wall.
  4. Offset the next row creating a staggered pattern. If your wall has a straight edge, you will need to cut the first block in half to create an offset. Continue this offset for each of the remaining courses. Occasionally checking that the blocks are level and “hooked” to the block below it.
  5. If desired, top off your last course of concrete block with topper stones.
  6. Backfill your new retaining wall using a Mini- Excavator.Start by placing gravel against the backside of your wall. Add a drainage pipe, if desired.  Next, backfill dirt behind the gravel. Tamp down every now and then to secure the dirt.

Have more questions about building a stackable concrete block retaining wall? Talk to the experts at Northside Tool Rental for answers to all of your project questions.