Many clients have asked what kind of stone walls would be better for their landscaping project. There are many things that factor into that ultimate decision. First, we need to explain what a stacked stone wall is.
A stacked stone wall is stone rocks that are usually flat on all sides and get stacked up to form a focal wall or retaining wall. See the image below for reference. Most clients want something 2 to 4 feet height that defines a space or borders an area, such as a planting bed or pool area. The wall can be however long, but restrictions are introduced after a certain height. Permits may be needed for much higher wall plans. Stone walls are a beautiful focal point and addition to your outdoor space and can last for hundreds of years when built properly. The style of the rock is essential as well in the build. Stone walls vary in color and texture, but at Allenworks Landscape, we have our popular go-to stones that almost all clients love.
WET STACK WALLS ( MORTARED)
Wet stack walls are useful when rocks that may not be level on the bottom or top and need mortar to keep the levels of stacked rocks together and looking uniform. More rocks used equals less rock waste. Another reason may be that there is no barrier, such as land behind the wall, to keep it stable and upright. A wet stack is durable against weather and is considered a rigid structure. The height of a wall plays an important role as well. If the wall is too high, mortar may be necessary to engineer the structure properly. A wet stack is also easier to build because the mortar acts as a buffer between rock shapes. At Allenworks Landscape, we prefer not to use mortar as it adds an unnaturalistic look to the wall. Mortar is not natural in our eyes, but that’s our opinion. Material costs could be higher due to mortar and labor expenses.
Wet stack walls behind a structure like ground may shift over time, causing cracks in the mortar, loosening the rock, and may need patchwork, which can be unattractive. If the wall is compromised many years after, it could require all new sections and become costly with new materials.
DRY STACK WALL
All of our walls that have soil/earth behind them are usually dry stacked. Dry stacked walls also let rain and water flow through without causing damage and are very flexible. A dry stack wall takes more skill to build than a wet stack but also takes more rock and time. When we order rocks, there is usually a higher waste cost due to stones in pallets not being used due to their shape and form. Landscape Companies typically have no control over taking apart stone palettes at the rock yards, so we usually go on what we see from all sides. That said, the cost of rocks is generally more on a dry stack wall. In addition to the stone costs, the labor is higher due to the skill needed to piece each rock so that it stacks perfectly. Behind the wall, the dirt is continually added and packed per layer of stone with a fabric water barrier to allow water to pass through but not land and silt. After the earth is packed in, we add gravel to each layer to give backing support to the wall side where the rocks have spaces that need to be filled. The process is genuinely complex but is also very rewarding. The look of the result is breathtaking, and it is structurally sound. We love the look and the outcome.
At the top of a dry stack, we usually put a top stone or cap rock held in by mortar. The top caps are the only location we use mortar. On one of our recent projects, we capped the wall with sandstone mantles, a mortar base, and joints to color match the stone, as shown in the picture below. If future repairs are needed, removing and replacing sections of stone is much easier.
The key differences between each method boil down to the structural application of what the wall is. If you are building a wall open on both sides, then you would use a Wet Stack. If the wall height were over a specific measurement, then a wet stack would be the way to go. A dry stack is the preferred option if it’s a wall under 4 feet and has ground behind it. Whatever your needs, let Allenworks discuss the differences with you and help make your vision come to life.