A flagstone wall is a wall that has been constructed from flagstone, a type of sedimentary rock which has been valued in construction for centuries. Flagstone walls can be used as retaining or decorative walls in gardens and landscaping features, and they are also utilized to fence in animals, or as the walls of a home. Installing a flagstone wall requires the service of a skilled mason to ensure that the wall is laid properly, as he or she can lay out and execute an effective masonry design.
Rather than being a specific rock, flagstone is actually a family of related rocks, all of which share the characteristics of being close-grained sedimentary rocks which flake apart in layers. This flaking quality is what makes flagstone appealing, because the flakes can be broken into flat slabs which can be used in construction. Flagstone is often used in flooring, roofing, and paving in addition to walls, and it comes in a range of shades, including blue, green, gray, cream, rust, and brown.
There are two construction methods which can be used to make a flagstone wall. In the first case, slabs of flagstone are laid on top of each other to gradually build up a wall. Historically, these walls were sometimes made without mortar, with carefully chosen slabs which fitted together like puzzle pieces. In the modern day, mortar is usually used to make the wall more stable, ensuring that it will not be damaged by inclement weather and collisions from animals, falling trees, or vehicles.
In the second construction technique, a core is built and then faced with flagstone. The flagstone is laid flat against the wall, almost like a tile, and mortared to the base. Grout is then used to fill the gaps between the slabs of flagstone, creating an even appearance while strengthening the wall and protecting the base from water damage. A wide variety of materials can be used as a core, including concrete, cinderblocks, or wood. Flagstone can also be used to cap walls built from other materials, in which case the flagstone is mortared to the top of the wall and grouted.
The advantage to a flagstone wall is that when it is well constructed, it will last for decades with minimal maintenance. Flagstone also weathers very nicely, blending into the natural environment while complementing surrounding architecture and landscaping. The aesthetic look of a flagstone wall is also valued in some regions of the world, and the installation of such walls can elevate property values or increase interest in a property among prospective buyers.