In a row of arches the thrusts of neighbouring arches cancel over each intermediate pier, which may therefore be slender; at the ends of the row nothing balances them, so the outermost piers must be made wider or buttressed.
Quoins long and short
Bind the corners of a wall with dressed stones laid alternately long and short on each face, so that they bond into both walls and mark the angle of the building.
On a brick house the quoins are of stone, or of brick of a different colour, and sized to a whole number of brick courses; on a stone front they may be rusticated, every stone of a length with the joints sunk.
Related rules
Let the wall of a façade curve in plan (concave, convex, concave) so that the front answers the street, the light and the space within, and the order bends with it.
Rusticate the lowest storey or the basement, its stones marked by deep joints, as the plainest and strongest part of the building; keep the dressed stone, the orders and the ornament for the storeys above.
Mark the level of each floor on the front with a plain flat band of stone (a plat band), or with a moulded string course where the front is richer, so that the storeys can be read from outside.
Over a window in a brick front, turn a flat arch of soft red bricks rubbed and cut (gauged) to radiate from a centre below, laid with the finest joints, and give it a keystone of stone where the front is dressed in stone.
Glaze the sash windows in panes of equal size, three across: six over six on the ordinary storeys, six over nine on the tall windows of the principal floor, and three over three in the low windows of the attic.
Cite this page Chris Paton, “Quoins long and short”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/quoins-long-short. Text, drawings and models licensed under CC BY-NC 4.0.