Dry stack stone walls are a great way to add character and texture to your landscape, and they can be built at a variety of heights. You can use them for retaining walls, freestanding garden walls and raised planters.
How high can a dry stack stone wall be?
A dry stack stone wall is a natural, self-supporting structure that gains its strength from the weight of stones interlocking together. These structures are often used for a range of different purposes, but they are especially useful to keep warm-loving animals in and mark out a garden.
The highest walls can be up to 3.5 to 5 feet tall, depending on the stone you use and the size of your foundation trench. For best long-term stability, cut your foundation trench into native soil rather than loose bedding soil. Also, if you are building against an existing bank or steep slope, set the foundation of your wall back from the slope about 2 inches per foot of height for greater stability.
Using the correct stones and getting the basic design of your wall right (wide at the bottom narrowing to the top and leaning back into the ground it is holding back) will make your wall really strong. This will give your wall a solid, robust appearance and make it completely self-supporting.
How to Build a Dry Stack Stone Wall
Start by digging out a trench that is 8 inches deep and 6 inches wide on each side of your planned wall. Lay the first course of stones in this trench, spacing them about 1/2 inch back from the front of each other. Then, place the next course of stones on top of them, staggering their joints with those in the first course, like a 1-over-2 pattern of bricklaying.
This is called batter, and it helps the wall resist the forces imposed by the slope of the land. It also makes the wall more stable over time, as it prevents soil pressure from pushing the stones out.
Once the wall is in place, it can be covered with a layer of landscape fabric to help keep it clean and dry. You can also run drainage pipe through it if your yard has a lot of clogged rain gutters.
For the base course, choose the largest, flattest stones you have. Reserve the wider, smoother, and more attractive stones for the top course, known as capstones or coping stones in some areas. You can mortar these in place, or you can tip them slightly toward the face of your wall to improve drainage by inserting small flat stones under them.
Sort your stone into size groups, placing the largest stones in one group and the smaller ones in another. This will help you see which stone has the widest, flattest face so you can pick out the largest, flattest stone for your base course.
If you need to chip away projections from some of the rocks in your pile, you can do so on-site with a hammer and chisel. Do this to maintain the shape of your pile, and to give you the most uniform look for your finished wall.