Flagstone patios

What this covers

Flagstone is natural stone split into flat pieces, sold irregular or cut into squares and rectangles. The mason builds a compacted gravel base, then either sets the stones in sand or stone dust with the joints filled with gravel, sand or planted moss, or mortars them onto a concrete slab for a tight, formal surface. Irregular stone is a puzzle: each piece is chosen, trimmed with a hammer or saw, and fitted so the joints stay even and the surface walks flat. Thicker stone is used for dry-set work so it does not rock. The result is a patio that looks like it grew in the garden.

When to call

• A garden setting where concrete pavers would look too uniform.
• A path or terrace on a slope that wants to step down naturally.
• A patio around a fire pit or a seating area.

What to expect

1. Select stoneType, color, thickness and irregular or cut shape are chosen from samples.
2. BaseSoil is excavated, gravel placed and compacted, and the grade set to drain.
3. FitStones are laid out, trimmed and set level with even joints.
4. JointsJoints are filled with gravel, sand, mortar or planting soil and the surface cleaned.