Rules · Walls · Structure · Façades
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°)
The batter began in mud brick, whose walls are stable only if broad at the base, and passed into stone as a form. It gives Egyptian architecture its look of permanence: every mass is visibly planted in the ground. The pylon, two battered towers flanking a lower gate, became the sign of the temple itself.
A beam is squeezed along its top and stretched along its bottom; stone resists squeezing well but stretching badly, so a stone lintel must be deep in proportion to its span and cannot be long. Doubling the span quadruples the stress from its own weight.
σ ≈ ¾ ρ g L² ⁄ d (self-weight) · + ≈ 0.43 ρ g L³ ⁄ d² (a wall above)
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
Weight for weight, timber is many times stronger in bending than stone; long spans in trabeated buildings are therefore roofed with timber beams resting on stone walls and columns.
bending strength ÷ density: oak ≈ 70 · limestone ≈ 3 (kPa per kg ⁄ m³)
The royal tomb grew in about a century from a low battered mastaba, through a stack of diminishing mastabas (the step pyramid), to a smooth-faced true pyramid; a failure of stability in between forced the change of slope of the Bent Pyramid.
When a steep pyramid shows signs of distress, flatten the slope of the upper part: Sneferu’s pyramid at Dahshur rises at about 54° for its lower part and about 43° above.
lower seked 5 palms (≈ 54.5°) → upper ≈ 7½ palms (≈ 43°)
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.
Cite this page Chris Paton, “Batter the walls”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/egyptian-batter. Text, drawings and models licensed under CC BY-NC 4.0.