How To Build a Retaining Wall

Gravity Retaining Wall

There’s numerous applications for a retaining wall. People build these walls around planting beds and landscaping to add an aesthetic balance to their home environment. Others build retaining walls for water management or to hold back soil from steep hills or even mountains.

If you’re either of these people, you’re going to need to know what tools are required and how to get one started. Rent It Today aims to assist you with some tips when you begin your wall project this summer.

First, take stock of your tools and materials. There’s several necessary tools for this DIY project, so have them lined up before you start. Do yourself a favor and save some time and hassle.

  • GlovesHand Tool Rental
  • Safety Glasses
  • Shovels (digging and scoop)
  • Tape measure
  • Sledge-hammer
  • Torpedo Level
  • Mason’s string
  • Stakes
  • String level
  • Hand tamp
  • Wheelbarrow
  • 4″ chisel
  • Carpenter’s level

Gravity retaining walls are typically assembled by large construction outfits for commercial purposes. We’ll leave those kind of walls to the professionals, being as they require heavy equipment and large work crews to complete. For practical purposes, let us focus on personal/residential retaining walls. There’s a few extra materials you’ll need, depending on how big of a wall you’re building.

  • Masonry block (obviously)Concrete Block wall
  • Dirt for backfill
  • Geo-grid
  • Soil compactor
  • Drainage pipe
  • Gravel

1.) Starting out, you’ll need to dig out a trench where you want the wall to be. Compact trencher rentals are ideal for this step. Once you’ve dug out the desired length, you should level the soil of the trench floor with a vibratory compactor rental. The blocks will have a level base to begin from, limiting the chance of tilting. Use gravel at the base so water is drained easier.

Retaining wallThe photo to the left illustrates what happens to smaller, residential retaining walls that aren’t built on solid, level foundations. Over time, ground settling causes the insecure wall to buckle outwards as the back fill soil wins the battle against the wall.

2.) After compacting the foundation and getting the first couple layers of blocks set up, it’s time to put drainage pipe behind the wall. Installing a drainage system is essential to sustaining your retaining wall–especially if it’s over 4ft tall. Use gravel to back fill this drainage layer to allow for easier water irrigation. Walls bigger than 4th tall will require you to look into obtaining a building permit.Geo Grid Retaining Wall

3.) Depending on how big of a gap you have behind the wall, you’ll need plenty of topsoil and dirt to back fill the wall. The taller the wall, more need for wall resistance. With each row of blocks, it’s suggested you put one sheet of reinforced geo grid material behind the wall. When placed through the block pegs, the grid sheet will anchor the wall as dirt is loaded on top of it.

As seen on the right, the builder responsibly installs geo grid to ensure that the wall is supported and pulled back by the dirt caught in the grid net. Water is able to flow through the dirt and net to the base layer, where you have gravel and drainage pipe ready to catch water and carry it away from the wall. Every other row of blocks would be an ideal time to put a new net behind the wall.

Backfill retaining wall4.) One of the leading causes of retention wall failure is the lack of landscape fabric. The fabric prevents soil from entering the back fill gravel. With each layer you fill in with soil, it’s imperative you use the compactor to make sure the soil is packed behind the wall tight with no air pockets where the soil can settle.

When stacking blocks, you’ll find some fit better than others–go with the ones that fit. Walls constructed from mismatched blocks will create problems in weight distribution from the back-fill. Use a concrete saw if necessary to get a block the way you need it.

5.) Coming to your last row, you should use a layer of impervious soil at the top. Impervious soil blocks large amounts of water from soaking into the soil layers below. Failure to use such soil will result in water being trapped behind the wall. Soil will soak behind the wall at rates high enough to buckle the wall. Use a skid steer to back-fill larger amounts of gravel and/or soil for your wall. Congratulations, after sweat and toil, you’ve built a retaining wall!

Contact Rent It Today for Tool Rentals
If you need short-term rentals for any of the tools mentioned in this article, explore Rent It Today’s extensive rental listings offered by some of the greatest construction equipment rental companies nationwide. BlueLine Rental provides tool and heavy equipment rentals nationwide: concrete saw rentals, skid steer rentals and trencher rentals are included in that list.



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