Types of Flagstone
The term "flagstone" refers to sedimentary rocks that can be cut or split into layers, producing flat stones appropriate for landscaping and outdoor decorative purposes. A quarried stone, flagstone has a smooth straight edge if it has been cut and a ragged border if it has been split. According to Bob Vila, a leading U.S. expert on home renovations, most people recognize flagstone by its split-surface and uneven border, which give it a natural look.
Commonly found types of flagstone include limestone, bluestone, sandstone and volcanic stone. In addition, there are many specific kinds of flagstones found in particular states or regions of the United States. New Mexico buff flagstone, featuring a soft brown color, is easy to cut. Pennsylvania blue flagstone is known for its dramatic blue color. Arizona flagstone comes in colors that range from a vibrant red to a soft buff. Colorado flagstone frequently comes in a red hue but also can be found in muted beige tones.
Flagstone is found in a variety of colors determined by the binding materials that are part of its natural formation; consequently, flagstone colors vary by region. For example, if iron oxide is a dominant binding material, the flagstone will have a reddish tint. Common flagstone colors include white, brown, orange, red, gray and gold, and even lighter tones such as lavender and pink. As a design element, flagstone offers the choice of using uniformly colored stones or mixing and matching complementary tones.
Landscape architect Dean Hill suggests that consumers closely examine the quality of the flagstone they're considering purchasing. If you want the stone to retain its durability and beauty, don't choose stone that appears flaky, gritty or porous. If the surface isn't uniform, water may seep into the cracks and crevices after installation outdoors. The more solid the stone, the greater the chances it will remain sturdy and attractive for years to come.
Proper installation can determine not only how long flagstone lasts but also its appearance as time goes on. Hill recommends choosing a stone that's 11/2 inches thick for best results; pieces 1/2 inch thick or less are not a good choice for long-term projects. Using leveling sand to support the flagstones will minimize settling and help the stones remain in their original position. Flagstones should be supported all the way across with the leveling sand; a void could cause cracks in the stone.