Rules · Ornament · Entablatures · Walls
Finish every Egyptian wall, gate and shrine with a torus roll and, above it, a deep cavetto (the gorge) curving outward under a flat band.
The gorge cornice probably recalls the earliest walls of bundled reeds or palm ribs, whose loose tops bent outward under their own weight, and the torus the cord that bound their corners. Painted with vertical leaves and often carved with the winged sun disc over the doorway, it crowned temple walls for three thousand years, and returned in the Egyptian revivals of the nineteenth century and in Art Deco.
In a bonded masonry wall the courses above an opening corbel over it of their own accord, so the lintel carries roughly the triangle of wall with sides rising at 60° from its ends; everything above that triangle arches onto the jambs.
load ≈ equilateral triangle on the span: W ≈ 0.43 · L² · t · ρ g
Make the outer faces of pylons, enclosure walls and mastabas lean inward as they rise, so that the wall is thickest at its foot; mark the corners with a torus roll.
batter of pylons ≈ 1 : 8 (about 83°)
Model the column on a plant of the Nile (a papyrus stem or bundle, a bundle of lotus, a palm trunk), bound at the neck with five bands, standing on a round base disc and carrying a small square abacus.
Cut the obelisk from a single block of granite, square in section, tapering to about two-thirds of its base width, capped by a pyramidion, and about ten times as tall as it is wide; set them in pairs before the pylon.
height ≈ 9–11 × base width
Cite this page Chris Paton, “Crown the wall with a gorge”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/cavetto-cornice. Text, drawings and models licensed under CC BY-NC 4.0.