Stone, Flagstone, Fieldstone and More
Although some stone is suitable for use in walls as well as patios and walks, that suitability is determined generally by the size and shape of the stone. It's also worth noting that the names of stones are not necessarily consistent from one distributor to another. The term "rubble," for example, may include river rock and fieldstone at one retailer but not another. Be sure you understand how a dealer is using a term when you inquire about their stone.Stone for patios and walks
Flagstone is quarried stone fractured -- or cleft -- into flat slabs 1-1/2 inches thick or thicker. It is often used for paving and works well set in sand or mortar. Flagstone comes in many varieties; slate, bluestone, limestone, redstone, sandstone, and granite are the most common. Irregular shapes make it ideal for either free-form or geometric patios or walks. It is often used for stepping-stones.
Cobblestone is small stones of a relatively consistent size cut for use in walks or paths. Cobblestones are square or round, flat or slightly domed. Their surfaces have subtle variations in the visual rhythm. The stones' small size makes installation easy but time-consuming.
Cut stone is flagstone with straight-cut edges and square corners. Pieces range from about 1 foot to 4 feet wide. Thickness varies; cut stone for paving should be at least 2 inches thick to avoid breakage. You can install cut stone in the same manner as flagstone, but its overall appearance will be more formal.Stone for walls
Fieldstone is literally stone that's gathered from fields. It comes in various sizes and is almost always round. It's suitable for both dry-stacked and mortared walls. Some quarries offer split fieldstone with at least one cleft edge that makes wall-building easier. Some dealers include river rock, a smaller variety, in the fieldstone category.
Rubble is quarried small stone of irregular sizes, usually with one cleft face that makes mortaring easier.
Ashlar is cleft stone cut into fairly regular shapes with relatively flat sides. Ashlar stone comes in different thicknesses, a characteristic that makes an interesting look when stones are placed in alternate courses on either a dry-stacked or mortared wall.
Stone veneer is natural stone or a stone look-alike cast from concrete or synthetic material. It's cut or molded in thin sections for application as a cosmetic facing material on walls.Designing with stone
Stone's random shapes and varied surface textures bring a rough-hewn character to the landscape. Even in mortared installations, stone imparts a casual, rustic quality, effortlessly complimenting woodland, cottage garden, and natural design themes. The overall tone of a patio design is set by its contours more than the type of stone. Stepping-stone patios usually look casual. Sand-set and mortared patios can be formal or informal, depending on their contours. Dry-laid or sand-set stone doesn't require specialized skills or equipment and resists frost heave. Porous stone, however, may absorb water and crack in freezing temperatures. Natural depressions in flagstone can collect water and become slick when frozen. Slate is slick when wet.
Stone patios and walls can last forever with little or no maintenance. Stepping-stone projects require periodic weeding and occasional resetting and leveling. Mortared installations require a concrete slab and mortar bed. Large stone will cover an area more quickly than smaller stone but may prove harder to move, cut, and design.Pro Tip
Stone is generally sold by the ton or square yard. For a patio or walk, one ton of larger stone covers about 13 square yards. Before placing your order, determine your patio or walk's area or the volume of your proposed wall. Your supplier will convert this measurement to tonnage, if necessary.
For small projects, visit your garden center or building-supply retailer; some sell individual stones for small projects.
For a large project, purchase stone in bulk from a local quarry or stone yard. Order cut stone and ashlar on pallets to reduce breakage. Hand-picking your stone increases costs considerably. Stone native to your area is most economical.Design tips
To increase the formality of a patio design, keep straight edges on the perimeter or use modular edging, such as brick. Use large stones to pave large expanses of landscape, smaller units in smaller yards.
Unlike other materials, stone structures are best designed on-site. Lay flagstone into the side of the patio site and experiment with patterns and pleasing arrangements. Separate wall stone into groups of similar size and shape and intermix stones from these groupings as you create a design.