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How To Install A Block Retaining Wall

Want to learn how to build a retaining wall? Keep reading to learn the installation process required to build a beautiful Retaining Wall that will last for years to come. We’ll cover everything you need, retaining wall blocks, including tools, layout, equipment, base preparation, gravel selection, stacking, backfilling behind the wall, and installing the capstones (marking & cutting).


The wall is constructed from Allan Block Classic Collection in the Granite color.  The block retaining wall is holding up a paver patio and deck.
Block Retaining Wall Installation

Before we begin in most areas retaining walls 4ft tall and over require a permit or possibly an engineered drawing to legally construct the retaining wall. In some areas, the height restriction is 6ft tall and requires an engineer to design your retaining wall. So be sure to check your local codes to see what is required of you to proceed. Once you have engineered drawings approved by the city. You can begin construction, following the retaining wall blueprints exactly.


Retaining Wall Blocks

There are a few different styles of retaining wall blocks that should be considered for your project. Some are interlocking while others require the use of concrete adhesives and locking pins to create the structural bond.

Hollow Block style and Solid Block style both have interlocking features and/or require concrete adhesive.


Hollow Blocks are just how they sound, with a hollow center and durable perimeter. These blocks are typically taller than their solid block counterpart. The average Hollow Block is 8 inches compared to 6 inches with solid blocks. The hollow center makes it a bit trickier to persuade with your dead blow hammer (small surface area to hit)


Solid Blocks are completely solid and are about the same weight if not more than a hollow block. They are easier to use a dead blow hammer to level your block during base course install.


Fascia wall systems are composed of a core unit(s) that has features allowing a face unit to attach to it, in some instances concrete adhesive can be used for a more permanent application.


Some popular providers of retaining wall products are Unilock, Techo Bloc, Belgard, and Pavestone




Footer

Retaining wall footers should be composed of at least

  • 6 inches thick of gravel

  • 6 inches beyond the face(front)of the block

  • 18 inches beyond the back of the block- at least, sometimes farther

  • Average Footer is 3 ft wide or more by 10 inches deep

  • Footer drain with cloth covering or another filtering material

Anything less than mentioned above will decrease the integrity of your retaining wall project, likely failing.

Try not to disturb more soil than needed during excavation, if you do be sure to compact adequately.


Layout

Before beginning construction on your retaining wall, you should layout the planned excavation zone, the footprint of the footer, mark utilities, inspect grades and elevations.

  • Plan to excavate at least 6 inches beyond planned retaining wall footer

  • Mark utilities before excavation

  • Plan material staging

  • Where water will be directed from the footer drain

  • Setup grades stakes

  • Mark excavation zones with spray paint or stakes


Tools & Equipment

When you plan to build a retaining wall you are going to want some tools and equipment to help you get the job done. Maybe some helpers too, many hands make for light


work. Otherwise, you will likely need most if not all of the following:

  • Deadblow Hammer

  • Shovels-(flat and pointed)

  • String line & stakes

  • Levels:

  • Line level

  • torpedo(1ft or less)

  • 3ft or 4ft

  • 6ft

  • 8ft (optional)

  • Compactor - can be rented

  • Excavator- can be rented

  • Concrete saw- cutting blocks

  • Hammer & chisel