Let an element do more than one thing and belong to more than one order at once: a wall that is both inside and outside, a column that is both structure and sign.
Rules · Façades · Proportion · Use
The tall building has three parts
Treat a tall office building as base, shaft and top: an open, accessible ground storey for shops and entrances; an indefinite stack of identical office floors expressed as one; and a distinct attic that closes the composition.
base (1–2 storeys) + shaft (n identical storeys) + attic
Sullivan derives the division from use, not from precedent. The ground floor, for shops and banks, needs wide openings and easy access; above it every office floor is the same as every other, so they should look the same; and the top floor houses tanks and machinery, which Sullivan treats as the natural ending of the building, like the capital on a column. The analogy with the classical column (base, shaft, capital) is his own, but he insists that it follows from function.
In his Wainwright and Guaranty buildings the base is of stone with broad openings, the shaft is a screen of continuous piers (with extra, non-structural piers added between the real ones to strengthen the vertical line), and the attic is a band of round windows under a projecting cornice. The formula outlasted Sullivan: Art Deco towers and the postmodern skyscrapers of the 1980s both return to it.
Related rules
A building can carry meaning in two ways: as a duck, whose whole form is shaped into a symbol, or as a decorated shed, a plain, efficient shelter with symbols applied to it. Prefer the shed.
Speak two languages at once: the technical language of modern construction for the profession, and a language of familiar, historical or popular signs for everyone else.
The outward form of a building should arise from, and express, what the building does and how it is made, as the form of every living thing expresses its life.
At the street line a building may rise to a multiple of the street’s width; above that it must stay behind a plane drawn from the centre of the street, stepping back as it rises.
street wall H₀ = k × street width (k = 1 … 2½) · above it, 1 m back for every 2k m up
Over one quarter of the lot area, a tower may rise to any height, free of the setback planes.
tower footprint ≤ 25% of lot area · height unlimited
Cite this page Chris Paton, “The tall building has three parts”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/tall-building-three-parts. Text, drawings and models licensed under CC BY-NC 4.0.