Creating order out of natural chaos
Probably the most popular work I am regularly asked to do is to build patios and walkways out of random (or irregular-shaped) flagstone.
By the way, flagstone is defined as any natural stone variety that is available in thin slabs suitable for paving. Some kinds are able to be pulled out of the ground as-is whereas others are sliced from blocks of quarried bedrock. In the Seattle area there are dozens of available types of flagstone though most of them are from other parts of the country.
The way that the pieces are fit together has a pleasing look to the eye that many people are drawn to.
Strength and Durability: Building a Strong Base
Most of the stone patios commissioned around Seattle are built using a sand-set method. This means that no cement is used, neither a poured base slab nor mortared joints. Part of the reason is because of a less costly installation, but this method also allows for better drainage, is easier to repair in case of damage and takes less time to install. And when built correctly, it is functionally as strong as a full masonry application.
The way this strength is achieved is that the area to be paved is excavated around 6" deep and layers of crushed rock are spread and compacted with a machine. Then when the stone pieces are laid in place and leveled using the crushed rock, and this material is swept into the joints between the stones, the result is a smooth, level and durable surface that will not be undermined by ground water or shifting earth.
Flagstone Patterning: The Flow of Natural Shapes
Making an arrangement of flagstones like the one above that is pleasing to the eye and neatly fit is a rather long process. It involves using the stones the way they arrive as much as possible (to avoid waste) but cutting each one often multiple times to get these random shapes to work together.
A good stonemason knows how to make these lines intersect in a way that isn't awkward or ill-fitting and is also leveled in a way that creates a smooth and stable surface. Piece by piece these stones are vigorously worked into their ideal place where they will stay for potentially forever.