How to Build a Slate Wall

Measure out for the area you want to build your fence in, and outline the area with wooden stakes. Attach a string line to those stakes. Dig down with the shovel to a depth appropriate for your wall. As a general rule, you need at least 6 to 8 inches of gravel, 2 to 4 inches of stone for settling, the depth of the wall plus at least a few inches of stone under the ground level for stability.

Remove all of the stakes except for those outlining the face and/or outside edges of your slate wall. Attach a string level to the string, and level out the string so that you have a reference point to work with as you build the wall. You can raise or lower the string as necessary to check the levelness of the wall, both for flat walls and sloped walls since it is a reference line.

Fill the trench with gravel, and tamp it into place with a hand tamper. Pour the gravel into the trench in layers, such as 3 inches, and then tamp that layer down before adding another layer of fresh stone. Repeat the process until you are finished with the gravel, and then add a layer of sand. Tamp the sand into place.

Start stacking your slate stones, using the base of gravel and sand as the foundation layer for the first few rows of stone that are laid down below ground level. Work your way up, using alternating sizes of stone so that everything locks into place like a puzzle. Always ensure that the row above does not match the row below, and let the natural imperfections in size work to your advantage as you randomize the pattern.