Brick archways: forms, voussoirs and a keystone that locks the ring
Bosse Stoneworks describes its decorative work as complex geometric brick archways, grand stone entry pillars, and custom patio medallions, and the arch is where that claim gets tested first. An arch is carried on a timber form cut to the exact curve. The wedge-shaped brick or stone, the voussoirs, are laid up from both springing points toward the middle, and nothing holds until the keystone goes in at the crown. Every joint above the form has to be spaced correctly before that last piece is set.
That is why geometric patterns are a mason's job and not a finish carpenter's. A segmental arch over a garden gate in Aiken, a round-headed opening in a courtyard wall, a soldier-course arch over a window: each one pushes sideways as well as down, and the piers beside it have to take that thrust. The form stays in until the mortar has gained its strength, and the joints are tooled to one consistent profile so the curve reads clean from the street.
