DIY Rock Walls for Edges Between Grass & Rock Landscaping

Building a Dry Stone Wall

• You can build a very strong and long-lasting wall using the dry stack method. According to King's Product Development in British Columbia, some Cornish walls in existence today date back as far as 4000 B.C. For strength, your wall must be constructed on a level, solid base. Dig a trench about 6 inches deep, and as wide as your widest stones. Place the first layer of stones in the trench as tightly together as possible. As you stack the next layer of stones on top of them, stagger them a little so they don't join in a continuous line from bottom to top. Save the smoothest, flattest stones to finish off the top.

Making Use of Gravity

• Rocks of irregular shapes and sizes must be fitted together in an interlocking manner if they are to stay in place as a dry wall, which are held together with gravity and friction instead of mortar. Build your wall of large rocks as a backbone and fill the gaps with smaller rocks for stability. For additional strength make the best use of gravity by placing the larger rocks at the bottom and slanting the wall inward about 1 inch per foot as you build. The taller the wall, the wider it should be.

Retaining Walls

• The height requirement of your wall makes a difference. If simply used as a border, a row of rocks along the edge between grass area and rock landscaping will do the job. If the stones are used as a retaining wall between a high and low area, you would need both correct height and strength. Mortar between the rocks will stabilize them but today, according to the National Center for Preservation Technology and Training, the dry stone method is increasingly the choice. Choose a practical height for your wall to serve its purpose. Strive to finish off at the top with rocks that are level with each other.

Building a Wall With Mortar

• If you choose to use mortar instead of the dry wall method, do something creative such as a mosaic in rock. A wheelbarrow is a good container for mixing mortar. A readymix is fine. Mix the mortar in small batches after you've dug a shallow trench for your wall. Place a blob of mortar in the trench and set a rock on top of it. Continue this procedure the full length of the trench. Place mortar on top of these rocks one or two at a time. Add another rock on top of the mortar. Continue to do this, forming your mosaic pattern as you build upward. Clean off excess mortar while it is still damp.