How to Build a Brick Retaining Wall Around a Hot Tub

Mark out the location of your retaining wall with marking paint. Mark both edges of the wall. To get the width of the wall right, line up two of your bricks side by side running left to right; you want the wall to be two bricks thick. Mark the back of the wall 2 to 3 inches behind the bricks. Be sure to mark any corners or curves as well, keeping the width of the wall fully consistent.

Dig out the area between the lines of marking paint. Dig to a depth of 6 inches plus half the thickness of the brick. For instance, if the brick is 2 inches thick, dig to a depth of 7 inches. This will ensure that you can bury half of the bottom layer for stability.

Rake the bottom of the trench with a steel rake to remove any large stones or debris. The bottom of the trench must be fully level. Once you've gotten the bottom flat, compact the soil with a hand tamper.

Fill the entire trench with 2 inches of crushed gravel or patio base material. Spread it with the steel rake to ensure that it is completely flat and uniform all the way around.

Wet down the base material with a hose to reduce dust, and compact it with the hand tamper to ensure that it is fully flat and stable. Repeat adding another 2-inch layer, flattening and compacting, followed by another layer until you have completely filled, leveled and compacted 5 inches of the trench.

Top the base material with a 1-inch layer of coarse sand. As before, spread it around evenly and dampen it. Do not tamp it down, however; just use the rake to make sure it is fully level.

Dampen the bricks you will install with a hose. This will prevent the bricks from absorbing moisture through the mortar you will use. Allow these to dry out slightly while you work with the mortar.

Mix brick mortar and water in a wheelbarrow or bucket per product instructions. When mixing is complete, you should have a plastic-like consistency with no lumps or chunks of mortar.

Set the first brick onto the sand pressed firmly against the front of the trench. Place the first brick in the other side of the wall directly up against the first brick you laid. The bricks should be partly buried.

Run a level across the two bricks both vertically and horizontally to ensure that they sit completely flat. If necessary, tap the bricks into place with a rubber mallet.

Lay the bottom layer of bricks in both rows, checking the level of each brick as you go. If necessary to go around curves, cut a brick with a hammer and chisel to make small corners to run around the curves. Continue until the first row is complete.

Cut one-quarter of the length of the brick off the first brick in the second layer of each row. This will ensure that the joints of the wall are staggered for best support.

Spread a 1-inch layer of mortar across the first two to three bricks in each row with a flat mason's trowel. Start the second layer of each row with the three-quarter piece of each brick, pressed firmly into place in the mortar.

Check the level of the first bricks of the second layer, tapping the bricks further into place if necessary with the brick hammer. Wipe away any excess mortar that runs from beneath the bricks with a damp sponge.

Build the second layer of the wall by running 1-inch-thick layer of mortar across the top of the previous bricks and tapping the new bricks into place. Finish the second layer with the one-quarter pieces you cut off before.

Backfill the trench in which you are building the wall with crushed stone to facilitate drainage. Fill in the remainder of the trench behind the wall and then compact the area.

Build up the wall, use full bricks to start the third layer, cut bricks to start the fourth layer, and so on until the wall is complete. Remember to check level and clean up mortar as you go. Allow all mortar to dry for at least 48 hours before using the hot tub.