If you are considering Pennsylvania bluestone as the material for your patio or other outdoor living project, you have several additional decisions to make: Shape, texture, color, thickness, and quality. This article discusses the options for shape and texture. The range of shape and texture options is far greater than you might expect.
Two basic shapes are available: irregular and pattern. A piece of irregular flagstone is generally two to three feet wide by three to four feet long with a completely random amoeba-like shape. Irregular flagstone is packaged in a pallet vertically or standing up which is why it is often called “stand-up” flagstone. Pattern flagstone is cut at the quarry into squares and rectangles in a large selection of sizes. Standard sizes (in inches) are 12×12 up to 24×36 in six inch increments (i.e., 12×12, 12×18, 12×24, 12×30, 12×36, 18×18, 18×24, 18×30, 18×36, 24×24, 24×30, 24×36). Because of the range of measured sizes, pattern is also referred to as “dimensional” flagstone. Larger pattern sizes are less readily available. Smaller patterns sizes are re-cut from broken pattern and used for tumbling only.
Three textures characterize flagstone: Natural clef, thermal, and tumbled. Natural clef is the irregular somewhat wavy surface that is created by nature when flagstone separates or splits along natural fault lines. Thermal refers to the effect created when flagstone is cut and then flamed to remove any irregularities. Thermal is completely flat but has a slightly bubbly surface (almost like a manufactured non-slip finish) created by the flaming process. Tumbled flagstone is literally tumbled in a machine similar to a large drier. The tumbling process smooths the top and bottom of the flagstone and breaks off sharp edges leaving a soft rounded edge.
Both irregular and pattern are available natural clef, thermal, and tumbled. Perhaps obviously, these combinations of shape and texture result in a huge range of options. And, options can be combined, e.g., natural clef pattern patio with irregular natural clef sidewalk. Be sure to see samples of the textures and shapes of PA Bluestone Flagstone you are considering before making your final decision.