Where the roof is of timber, make the columns tall, slender (about twelve diameters) and widely spaced, and fill the hall with them on a square grid.
height ≈ 12 D · spacing ≈ 5 D (Apadana: ≈ 19 m, D ≈ 1.6 m, axes ≈ 8.7 m)
The square hall of columns
Make the hall square and fill it with columns on a square grid; put a portico two columns deep across the front, between solid corner towers; build the walls of mud brick and keep stone for columns, door and window frames.
Every hall at Persepolis is a variation on one plan, first seen at Pasargadae: six by six columns in the Apadana, ten by ten in the Hundred-Column Hall, four by three in the palace of Darius. Because the roof was of cedar beams carried on slender columns rather than on vaults, the grid could be as large as the timber allowed. The mud-brick walls have vanished; what stands today is the stone skeleton of door frames, window frames and a few columns.
Related rules
Crown the Persian column with two kneeling bulls (or lions, or griffins) set back to back; lay the main beam in the saddle between their necks, and the cross-beams on their heads.
Dig the foundations down to bedrock and fill them with rubble; then build with the best material of every province, each worked by the people who know it best.
Cite this page Chris Paton, “The square hall of columns”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/persian-columned-hall. Text, drawings and models licensed under CC BY-NC 4.0.