Rules · Vaults · Plans · Proportion
Keep the span of a corbelled room to about three metres or less and make it long instead of wide; to enlarge a building, add parallel galleries rather than widening them.
Maya room spans ≈ 1.5–3 m; vault rise ≈ 1–1½ × span
Because every course must overhang only a little, a wide corbelled room needs a very tall vault and very heavy walls. The rooms of Maya palaces and temples are therefore long, narrow and high, often in pairs or ranges of parallel galleries sharing a central wall, as in the Palace at Palenque. The walls are massive in proportion to the rooms they enclose; in temples the solid often exceeds the void.
Build each stage of a platform as a sloping talud surmounted by a vertical tablero: a rectangular panel framed by a projecting border and cantilevered slightly over the slope below; repeat the pair at every stage.
Teotihuacan: tablero taller than talud (often ≈ 1½–2 × its height)
Align the principal avenue and every building of the city to a single bearing (at Teotihuacan about 15½° east of north) so that the whole city shares one orientation with its great pyramids.
In a corbelled vault each course may project only a little beyond the one below, and each overhanging half must have its centre of gravity behind the inner face of its wall; load the tails of the stones with heavy hearting until the capstone is set.
stable if Σ W·x (behind the springing edge) > Σ W·x (in front)
Orient the principal axis of the monument on the rising or setting of the sun at a solstice, so that the architecture frames it.
Put the temples and their plazas at the centre of the town; round them the houses of the lords and priests, then those of the leading people, and the houses of the common people at the outskirts.
Build the house of wood and daub under a steep roof of thatch or palm, to throw off the rain; divide it along its length by a wall, with a whitewashed front room for receiving guests and a back room for sleeping.
Cite this page Chris Paton, “Corbelled rooms are narrow”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/corbel-span-limit. Text, drawings and models licensed under CC BY-NC 4.0.