Landscaping with Stone

Stone walls not only complement and enhance landscaping, they become enduring and unique features. Unlike wooden fences and retaining walls, stone walls will never rot or require repainting. If properly constructed, they will stand the test of time. Ireland is a beautiful example of the charm and durability of stone walls. Although the early peoples and their wooden structures are distant memories, they have left a legacy in stone. It is said that there are over 386,000 km (240,000 miles) of stone walls in Ireland. In the New World, stone structures nearly 400-years-old remain intact. One of the oldest of these was built in 1607 in what is now Portland, Maine. For early settlers, stone walls were essential - they kept out wildlife and protected precious livestock.

Today, stone walls serve a more decorative function although they remain very useful for garden plots and privacy. Stone blends with the natural landscape and the unique colour and shape of each stone means no two walls will ever be the same. Depending on the size of the project, the supply of stone can be free. In most areas of the country, our yards are a rich source of fieldstones as anyone who has cleared a garden plot will attest! For larger projects, there are a number of sources of stone: stone suppliers, quarries which sell the small pieces of rock which are unusable for them but perfect for a stone wall, or construction sites which unearth stones when digging a home's foundation.

Another option is to reuse stone from other structures. If there are abandoned stone buildings or walls in your region, contact the property owner to see if they would be willing to sell the stones. You may find that the stones have already been chosen or chiselled to have flat faces and square corners. These "old" stones can greatly reduce the work involved in building a wall.

When purchasing rock from a quarry or stone supplier, you can provide an estimate of the amount you will need by calculating the approximate volume. This volume equals height multiplied by length multiplied by depth. Remember that for optimum stability, the depth of a wall should be at least one-third of the height.

There are three basic types of stone to choose from: fieldstone which is often smooth and slightly rounded, stacking stone which is slightly flat usually due to the nature of the rock itself e.g. slate, and dress stone which is cut to be uniform and flat. When purchasing stone you can choose from sandstone, granite, limestone, quartz and slate among others. Consider these factors when making your decision: availability, durability (sedimentary rock is the least durable), colour and texture.

Building a wall that will last for generations begins with a firm, flat foundation. It is important to start with soil that has been cleared of large stones (more than 3 cm in diameter) because frost can cause rocks to heave to the surface. Over time, this movement can destabilize your wall. Dig a trench that is 10 cm deep and 10 cm wider than the intended depth of the wall. Level and flatten the soil at the bottom of the trench. Add a shallow even layer of fine gravel approximately 3 cm deep. Lay down a board and walk on it to press down the soil and gravel. Then place a carpenter's level on the board to ensure the surface is flat.

Now you are ready to start building. Although it might seem logical to put all the large stones on the bottom and get progressively smaller, in fact, this is not the case. The best approach is to mix large and small stones throughout the wall. Small stones placed in the spaces between larger stones are the key to durability.

As you begin placing rocks on the wall, you may find that some rounded or irregular edges need to be flattened. You will need to use a chisel and a large hammer, possibly a sledgehammer depending on the size of the stones. Ideally, you should have two chisels in different sizes - one-inch (2.5 cm) and two-inch (5 cm) - depending on the size of the stone. When doing this work, wear safety goggles and steel-toed boots. Use moderate controlled force when hitting the chisel; hammering the stone too hard may cause it to shatter or break unpredictably. It may take a few hits to get a good result.

The placement of stones is crucial to the stability of the wall. Remember this golden rule: one over two, two over one. In other words, when you have two stones butted together in a layer, place one stone over the seam in the next layer. Likewise, where you have a long stone in one layer, in the next layer place a seam between two stones over the length of the long stone. Use handfuls of crushed screenings to help stabilize wobbly stones and level uneven surfaces as you build the wall.

Another important rule in stone building is to use large stones at the corners for stability. It is also recommended to use large stones (cap stones) on the very top layer. The extra weight of these rocks will help stabilize the wall.

As you build up from the ground it can be difficult to maintain a straight wall without some assistance. Drive stakes into the ground every two metres along your wall at a set distance from the wall (a few centimetres is best). Wind string tightly around the stakes. Use the string as a guide when layering on the stones.

There is an important exception to straight walls. When building a retaining wall, the stones must very slightly lean back into the soil they will be retaining. As the roots of your plants grow and as the soil expands and contracts with changes in temperature, the soil exerts pressure on the wall. If your wall was perfectly vertical, it would eventually be pushed forward and fall apart. To offset this pressure, the wall must be built to tilt slightly into the soil. To do this, set each higher layer (also called a course) of stone back about 1.25 cm (0.5 inches), creating a continuous back-leaning slope or face.

Stones can be surprisingly heavy particularly at the end of the day! It's important to protect your back with a few safety measures. When moving stones, use a sturdy wheelbarrow. Bend your knees and use your leg muscles rather than your back to do the lifting. Wear a back support. When prying up large stones, use a lever action: slide a shovel as far as possible under the stone and work it up using a lever action by pressing down on the end of the handle with your body weight.

Now that you know the basics of building a stone wall you may wish to plan your own project. It's a good idea to draw out your ideas and measure the area where you would like to have a wall. When you have an idea of height, length and depth you will be able to calculate the volume of stones you will require and whether you get them from your backyard or from a quarry. A stone wall can be a beautiful asset to your landscaping and a enduring expression of your hard work.

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