Flagstone

Flagstone is a generic term for flat, naturally layered stone slabs used for paving, roofing, and flooring. It is typically a sedimentary rock—most commonly sandstone, but also limestone, shale, or sometimes quartzite or slate—taken from a quarry and split along natural bedding planes to produce broad, thin slabs.

Slabs are usually 1 to 3 inches thick (2.5 to 7.5 cm), though thinner or thicker pieces are cut for specific projects. Color varies by stone type and deposit, ranging from warm tans and reds to grays, greens, and blues. Surfaces may be smooth sawn, lightly textured, or rough-hewn; some are finished with a tumbled or bush-hammered texture to improve slip resistance.

Flagstone is widely used for outdoor paving (patios, walkways, steps, and garden paths), as well as interior flooring in rustic or traditional spaces. Proper installation requires a stable sub-base, usually crushed stone or gravel, a compacted setting bed, and appropriate joints. For outdoor use, drainage and weather exposure are important; expansion joints and edge restraints prevent cracking and movement.

Natural flagstone is durable in many climates but can crack in freeze-thaw cycles or when moisture enters joints. Sealing is optional and can help with stain resistance, depending on stone type. Periodic cleaning and resealing may be recommended for some surfaces.

Quarry sources include North America, Europe, and Asia, with production varying by stone type. Because flagstone is a natural product, color and thickness can vary between batches.