How to Make a Lava Wall

Choose the location for your lava rock wall. If you want to turn the wall into a waterfall, choose a location near a power source. Based on the size of the location and the desired height of the finished wall, draw a sketch of what you want the wall to look like, indicating desired dimensions.

Dig a trench 6 to 18 inches deep the same width and length you chose for the wall in the prior step. The depth depends on the chosen depth of the wall. Use 6 inches for a 1-foot wall and 18 inches for a wall up to 4 feet tall. The trench gives the wall support.

Lay the first layer of lava rocks in the hole you dug. Place the rocks flat on their sides, close together. After the laying the first layer, if the rocks do not stick over top of the top edge of the hole, add a second layer. When choosing rocks to lay, choose rocks of similar dimension on each layer.

Prepare a 30 lb. bag of concrete in a large bucket. Add enough water to create a pudding-like consistency. Stir to combine. It will remain somewhat lumpy.

Transfer the concrete onto the top of the rocks in the hole. Use a trowel to smooth the concrete into an even 1/2-inch layer. Press the concrete into the spaces between the rocks.

Place a second layer of lava rocks on top of the concrete layer. Choose rocks of like dimensions.

Repeat Steps 5 and 6. Adding additional layers of rocks and concrete until you reach the desired dimensions for the wall.

Fill the hole around the water, if necessary, with soil.

Let the concrete set for at least one week before adding water features or planting around the wall.