How to Build a Lava Rock Wall

Using your tape measure, figure out how long of a wall you will need. For a small rock garden, you can measure a space between two of your favorite bushes or trees, and put your rock wall in this location.

Take the shovel, and dig a shallow trench, following the desired length of your wall plans. The trench shouldn't be more than 10 inches across, and no more than a foot in depth. If you live in a dryer climate, you may want to spray the trench down with a garden hose to make the earth more pliable.

Begin placing the largest of your lava rocks into the trench, lining them side by side. It may be necessary to repeat this a couple times until the rocks protrude above the surface of the trench.

Put on the protective goggles and gardening gloves, then mix the cement mix in a 5-gallon container by adding water from the garden hose. Mix the cement thoroughly until the cement is at an oatmeal-like consistency.

Use your shellacking tool, by scooping generous globs of the mixture onto it, and slap it onto the topmost parts of the exposed lava rock. Make sure to get liberal amounts of the mixture into the gaps between the rocks as well.

Carefully place another layer of lava rocks, on top of the cement covered formation. You will need to take your time, and pair the rocks together by comparing the shapes and sizes like a jigsaw puzzle. This is to assure that the rocks are able to bond to the cement more easily. Repeat this step several times, until you are out of lava rocks of the desired size.

Using the remaining cement mixture, and the leftover rock segments from the pile, seal any large gaps and repair the areas that are less appealing than others. Most truck loads of lava rock will come with at least 20 pounds of broken and small chunks of rock, and they are very useful for this process.