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.
A gap between houses
Do not build party walls: leave a narrow gap between neighbouring houses, to carry off rain and waste and to stop fire running along the row.
In many bastides the houses do not touch. A slot a few tens of centimetres wide, an androne, runs between them from the street to the gardens behind, taking the drip from the eaves and the drainage of the yards, and acting as a firebreak between timber floors and roofs. Many were later built over or filled in, but they can still be traced in the plot lines of the old towns.
Related rules
Gather the weight and thrust of the vaults onto a few points by ribs, carry them down piers and out across the aisles by flying buttresses to external buttress piers, and the wall between the supports carries almost nothing, so it can be opened into windows.
In a timber-framed house, let the floor joists of an upper storey run out beyond the wall below and carry the upper wall on their ends: the upper storey oversails the lower by a foot or two, gaining room upstairs and sheltering the wall beneath.
Run a shaft or pilaster from the floor, up the face of the pier and the wall above, to the roof or vault, so that the long nave wall is divided into a sequence of vertical bays, each containing one arch of the arcade and the windows above it.
Build the monastery, if possible, so that everything it needs (water, a mill, a garden and the various crafts) is inside the enclosure, so that the monks need not wander outside, which does their souls no good; and set a wise old monk at the gate, with a cell beside it.
Lay out a new town with the cord on open ground: straight streets crossing at right angles, running through from gate to gate, blocks of equal size between them, and a square in the middle; then, when the town can afford it, enclose the rectangle with a wall.
Cite this page Chris Paton, “A gap between houses”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/bastide-andrones. Text, drawings and models licensed under CC BY-NC 4.0.