Home Improvement Expert Danny Lipford

How to Build Retaining Wall Corners

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Retaining wall with curved 90° outside corner

Retaining wall with curved 90° outside corner.

How do you construct 90° angle corners when building a stackable block retaining wall? -Adolfo

Constructing corners can be tricky when building retaining walls, since some types of blocks aren’t square and may not be textured on all sides. That’s why it’s important to consider your corners and curves carefully when choosing the type of block to buy for your retaining wall.

Some types of blocks come with corner units that make the job easy, and others are finished on all sides so the corners can be exposed. When choosing and buying blocks, make sure you have the accessories and instructions for whatever corners, curves, or special circumstances you have in your plan.

Here are some tips for tackling corners in your retaining wall project.

Retaining Wall Corners Using One-Sided Blocks

The most common blocks for retaining walls are textured only on one side, with a lip at the back that butts up against the row under it. They’re often wedge-shaped to allow for turns and curves. This type of block is designed more for curves than sharp corners, since only one side of the block is meant to show.

To construct retaining wall corners using wedge-shaped blocks:

  • Outside Corners: Most retaining wall outside corners built with wedge-shaped blocks are curved, rather than a 90° angle, since it’s impossible to make an outside corner without showing the cut (and unattractive) end of the blocks. Wedge-shaped blocks are easily laid in a curve, or you can cut the sides of rectangular blocks to achieve the same curved effect.
  • Inside Corners: It’s easier to construct 90° angle inside corners with wedge-shaped blocks, since the backs and sides of the blocks won’t show. Start the first row in the corner, then overlap the joints in each additional row of blocks, cutting any odd sized blocks to fit.
Retaining wall with 90° square corner

For 90° angle outside corners, use blocks that are finished on two or more sides.

Retaining Wall Corners Using Corner Units

If you’re using stackable blocks that are only textured on one side, the best solution is to choose a block system that comes with corner units. The corner units are finished on two sides and connect to the adjoining blocks to form a 90° angle.

Each system is designed differently, so each type of corner unit will have slightly different installation instructions. In general, you’ll start at the corner and work your way out, beginning with a corner block that alternates facing right and left on each row.

Drawing of blocks being laid on 90° angle retaining wall corner

Use masonry adhesive when constructing a 90° outside corner on a retaining wall.

Retaining Wall Corners Using Multisided Blocks

If your retaining wall blocks are rectangular and finished on at least two sides (like many pavers and cinder blocks), you can easily stack them to create a corner. Alternate the pattern to divide the load and keep the corner from splitting, and be sure to use some masonry adhesive to hold the corner pieces in place:
Julie

Further Information

Retaining wall systems and corner installations:



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