Building a Stone Wall: A Step-by-Step Guide

Long before written language, constructing with stone was one of humanity's oldest and most lasting traditions. Stone walls still stand in Britain, some dating back to 3500 B.C. While modern methods for defining outdoor spaces are simpler, cheaper, and quicker, none quite match the unique look and character of a stone wall. This timeless craftsmanship continues to be cherished, whether in a bustling city or on a remote farm. With just stone, gravity, and creativity, stone walls still offer some of the most satisfying solutions.

Be warned, taking on the task of building a stone wall is no small feat. The weight of the stones and the cost involved are no light matter, and constructing such a wall requires as much mental effort as physical labor. Think of the stone walls that have graced the New England countryside for decades, or the centuries-old walls in the United Kingdom. Imagine your own wall enduring for generations to come.

In this article, we’ll explore the various options and decisions you’ll need to make when building your stone wall, along with the tools and materials necessary for the job. Our primary focus will be on the dry-stone method, although it’s worth noting that most stone building projects today involve some concrete. Mortared walls, where construction paste is used between stones as a bonding agent, are a popular alternative, but we’ll concentrate mainly on dry-stone walls. These walls rely on gravity for their stability, making them more challenging to build correctly, but the principles apply to both types of projects.

Key Decisions to Consider

First, consider whether you plan to tackle this project solo. We’ll assume you’re going it alone, but much of the information in this article will still be valuable as you work through your project and finalize the details, even if you decide to enlist help. One major cost consideration is the price of transporting the stone to your site. In fact, the cost of the stone could be one of the biggest expenses, potentially even exceeding the cost of hiring a contractor. A relatively short wall could cost thousands of dollars just in stone, depending on how you source it. However, if you're a DIY enthusiast, you've likely already accounted for this, as well as the time investment. Even experienced dry-stone wallers typically only manage about 3.2 yards (3 meters) of wall per day [source: Henley]!

Choosing the right location for your wall is critical. Besides considering zoning and licensing issues, you’ll also need to think about your neighbors. If you're planning to build a boundary wall, make sure you don't construct it directly on the property line unless you’ve agreed to share responsibility for the wall. Ideally, the stone used should come from local sources, both for aesthetic reasons and to minimize transportation costs. Plus, local stone will weather more predictably over time, contributing to the wall's longevity.

Similarly, assess the land carefully before you start building. A seemingly harmless tree might grow into a massive one, with roots extending far beyond what you can see. Even a slight slope can significantly impact how your wall will evolve over time. Gravity plays a crucial role in all stone construction, and whether you're using mortar or dry-stone techniques, you’ll be relying on this powerful natural force to keep your wall intact for many years. It's said that stone walls are in constant motion, meaning that how you build it now will determine how it behaves for the rest of its existence.

Understanding Stone Selection

For constructing a dry-stone wall, it’s important to choose a hard, flat-cleaving stone, such as shale, slate, or schist. You want stones with flat tops and bottoms, so look for rocks that naturally break into those shapes to ensure a strong and lasting wall. Avoid igneous rock, as it forms irregular shapes that don’t work well in wall construction. However, if you’re drawn to the appearance of igneous stones, the option of a mortared wall remains available, as you’ll see.

Sedimentary rocks, shaped by time and gravity, offer a good alternative as well, as they form in similar useful configurations as the harder stones mentioned earlier. Though sedimentary and metamorphic rocks may be softer, they can still be a great choice, as you may need to do a bit of stonemasonry to make them fit. Keep in mind that 'soft' is a relative term: Sandstone and limestone, both sedimentary rocks, can endure for thousands of years!

Ultimately, the choice of stone depends on the environment where you're building: Strong winds from a dry, dusty plain can wear down limestone over time, while areas with frequent freezing and thawing cycles tend to fare better with softer stones, as they’re less prone to cracking and changing shape. Accounting for these natural forces is a crucial part of the wall-building process, and considering them from the very beginning will set you on the right path.

Your Plan of Action

Once you’ve cleared the entire site and considered the influence of gravity and drainage issues on the land, it’s time to start laying the groundwork for your wall. Whether you're using mortar or a dry-stone technique, it’s vital to plan out every detail: the wall's length, thickness, and how features like corners and gates will function.

Precision is key. One of the most important aspects of your project is ensuring that your decisions remain accurate. For instance, if your plumb line isn’t properly taut and is affected by the wind, your wall could end up being uneven. A line that you thought was straight might turn into a curved wall that will eventually crumble. On the flip side, if you're aiming for a curved design, you can use a garden hose or a thick rope to outline the trench for your first layer of stones and work the shape into the wall as you build.

When planning your wall, it’s crucial to follow some basic guidelines. For example, there’s a big difference between building walls shorter than 3 feet (0.9 meters) and walls that exceed this height. For a shorter wall, the base should be equal to the wall’s height. However, for walls taller than 3 feet, you’ll need to add an extra 8 inches (20 centimeters) in width for each additional foot of height. So, while a 3-foot (0.9-meter) wall requires a 3-foot base, a 7-foot (2.1-meter) wall would need a base of at least 4.6 feet (1.4 meters) [source: Vivian].

The charm of stone walling lies in its enduring nature: A big part of the job is keeping that permanence in mind. For example, the taller the wall, the deeper you’ll need to dig. If the wall exceeds waist height, make sure the trench is at least 2 feet (61 centimeters) deep — or deeper, depending on the frost line of your area. Frost can cause your wall to shift up and down, but by burying your dry stone wall, moisture can move through the gaps in the structure without disturbing it. For smaller walls, a depth of about 8 inches (20 centimeters) is enough: Gravity will take care of the rest, allowing the wall to settle into place [source: Volk].

Getting Ready: Materials and Tools

You’ve made your plan and you’re eager to begin building your wall. Before you dive in, ensure you have all the necessary materials on hand [source: Volk].

Mark your trench by placing stakes along the outer edge of your working area, positioning two stakes for every yard along the wall. Make sure these stakes are much taller than the final height of your wall, as you’ll be adjusting the line as you build. Once the stakes are secured, tie your string to them, starting at about a foot above the ground, ensuring it’s taut throughout.

The Footer

After digging your trench, begin by laying your "footer" stones. Depending on how deep your trench is, the first layer, and even subsequent rows, may be completely below ground level. Choose the largest, most irregular stones, as their odd shapes can be hidden in the earth. Place them several inches apart to aid drainage, and you can fill the gaps with smaller stones. If possible, try to create a shallow V shape along the center (the midpoint between the two walls) running the full length of the structure. This will provide a solid base for the following layers, where the outer stones support the ones in the middle.

Remember that gravity pulls straight down. This is the primary principle to keep in mind, as it helps make sense of the whole process. Start with a level foundation, and each layer you add will be pulled downwards, which is what will maintain the wall’s shape, hopefully for many years.

(For a mortared wall, this initial layer requires a full concrete pour, along with rebar -- steel reinforcement rods -- placed at six-foot intervals to the height of the finished wall. However, if you're building a dry-stone wall, you might also benefit from concrete here, though this would mean loosening your purist stance a bit to ensure a solid foundation. In that case, you would skip the rebar.)

Above Ground

Raise your guide lines to match the height of the first course -- or layer -- which should align with the size of your largest, thickest stones. Save the most uniform and attractive stones for the top of the wall, but prioritize placing the heaviest ones first so you won't have to lift them later, even if they’re visually appealing. Arrange them in parallel lines along the edges of your trench and fill in the gaps with less perfectly shaped stones. If possible, try to maintain the internal V shape, particularly at this early stage.

The goal is to achieve a relatively flat outer surface, but more importantly, maintain top-side flatness for the stones to follow. If you're using a dry-stone method, you've likely made some design decisions already, so focus on the outer vertical (the "face") only enough to avoid any strange gravitational effects caused by stones protruding oddly in certain places. Regardless of your technique, strive for flatness with each course.

As you work, ensure that each stone is as level and stable as possible. It's always better to shave off an uneven part of a stone or carve a chip from the one below than to wedge them together with smaller rocks or wedges. Save those smaller pieces for the interior of the wall, as any pebble you use to temporarily fix a problem will be the first to fall out when you leave. Once you've completed the first course, for a mortared wall, you'll end up covering the entire course anyway. If a stone would be perfect except for one flaw, the best way to fix it is to score that problematic part (no more than half an inch) with a chisel before attempting to remove it.

Every 6 feet (1.8 meters), you'll need a "tie" stone, which is laid crosswise rather than along the parallel edges. This stone literally connects the two sides of the wall, pressing down on the stones below, helping to unify the structure. The importance of these tie stones grows as you build upwards. A wall made up of two perfect halves isn't the goal -- it's the tie stones that provide the wall with strength and longevity.

Things Run Their Course

For each new course, simply raise your guide lines and repeat the process you used in the previous layers. Keep placing tie stones at the same intervals, use the imperfections of the layer beneath to level the surface for the next, and always keep an eye on your guide lines. Remember: If it's worth doing, it's worth doing right.

The only new consideration as you move beyond the footer and initial layer is avoiding vertical gaps in the wall's structure. Gaps between stones within a layer are known as "joints," and those that extend upwards are called "runs." You should avoid them, as they can be disastrous even if you've been careful with your ties. Stick to this straightforward rule as you build higher:

On the next level, cover a large stone with two smaller ones. Whenever possible, use larger stones to cover as many joints as you can. While this is crucial for exterior walls, don't forget it for the interior stones as well. A run that cuts through the center of your wall is a big mistake — it could cause entire sections to collapse.

The Big Finish

When working on corners, edges, and the top, aim for as much physical consistency as possible. Consider the corner and end stones as the most critical "tie" stones because they are highly exposed and essential for holding the structure together. These stones should be placed perpendicular to the wall, like other tie stones, but also serve as small faces to contain the smaller stones inside as they settle. This is especially crucial in mortared walls, where the structure relies on more than just gravity for stability.

The capstones at the top should be as long, flat, and uniform as you can manage while still keeping their weight manageable. While avoiding injury is important, it's equally crucial to prevent uneven weight distribution at the top of the wall. On the bright side, since you're no longer supporting additional layers, this is your chance to have a little fun with the final level of the wall.

As a final note, it's crucial to remember that, like any DIY project, maintenance is key. While you're building with the intention of creating something permanent, and striving to construct something that will endure, it's wise to monitor for any changes over time. Gravity may be slow, but it’s always at work, and issues may not appear immediately.

The beauty of building something by hand is that repairs are far simpler. If a section of your wall starts to show signs of trouble, you already know how to fix it — and you've likely practiced for just such moments. The way you've chosen to build your wall makes repairs effortless. A mortared wall with cracks? Just add mortar. A dry-stone wall? Simply stack another stone on top.