Stone walls possess a charm and beauty that few other manmade structures seem capable of paralleling. Building a stone wall using concrete mortar is a more involved process than a dry-laid stone wall, but it is a good option if you want your wall to have a more tailored appearance. Mortar is a mix of sand and masonry cement; you can either make your own or purchase pre-mixed concrete mortar. If you opt to mix your own mortar, Plymouth Quarries, Inc., a quarry company that provides stone for customers such as Yale University and Boston College, suggests that you mix 1 part masonry cement with 3 parts sand to create a satisfactory mortar blend for building your mortared stone wall. (see reference 1, page 2, paragraph 2)
Determine the width, height, length and location of your stone wall. As a general rule of thumb, the width of your mortared stone wall should be at least half the height of your wall; for instance, if your wall is going to be 3 feet high, then you'll want it to be minimally 18 inches wide. Use a garden hose to experiment with different wall layouts before you finalise the design. Sketch your stone wall design on a piece of graph paper with a pencil so you have a diagram to refer to throughout the building process.
Hammer wooden stakes into the ground to mark the corner and end points of your mortared stone wall. Tie a string to 1 of the stakes and run the string tightly between the remaining stakes to mark the front (face) of your mortared stone wall.
Dig a footer trench that is about 24 to 30 inches deep and 12 inches wider than your wall; 6 inches of the trench width should be in front of your marking string. Fill the trench with cement, levelling it with a 2-by-4-inch board. Let the cement set.
Mix your mortar in a wheelbarrow, adding enough water to make it about the consistency of thick cake batter; your goal is for the wet mortar to be just thick enough to retain its shape. Spread mortar across a 2 to 3-foot section of the cement footer in a 1 to 2-inch layer that corresponds in size to the width of your wall's base.
Position a single layer of stones across the top of the wet mortar, pushing each stone firmly into the mortar before moving on to lay the next stone. Continue spreading mortar and laying stones until you've mortared the entire base course of stone for your wall. Check with a level every 3 to 4 feet to ensure that the base layer is flat; mix additional batches of mortar in your wheelbarrow as you need it.
Spread mortar across the top of a base stone and press another rock into it to begin forming the second course of stone. Repeat this process for the entire second layer of stones, staggering the joints between the layers to help stabilise the wall. Continue layering the stones 1 layer at a time until your wall is the correct height.
Remove excess mortar squeezed from between the rocks during construction; wipe it away with a stick or piece of scrap lumber to clean up the face of your mortared stone wall. Use a damp cloth to remove any smears of mortar that you can't get with the stick.
Check with your city office about any building permits you may need to obtain before beginning wall construction.
Lift stones as little as possible to minimise possible back strain.