Rules · Walls · Doors & windows · Structure · Materials
Hang the outer wall from the edges of the floor slabs as a continuous skin of glass and metal, independent of the frame behind it, and express its grid of mullions.
skin = vision glass + spandrel panel per floor, on a module of ≈ 1.5 m
A curtain wall carries only its own weight and the wind, and transfers them to the slab at each floor through anchors. Early examples are the Fagus factory (1911–13) and the Bauhaus workshops (1926); after 1950 mass-produced aluminium and glass systems such as Lever House (1952) and the Seagram Building (1958) made it the face of the corporate city. At Seagram, bronze I-sections applied to the mullions are not structural: Mies added them to express the steel frame that fire regulations had forced him to encase.
The glass box’s weaknesses (solar heat gain in summer, heat loss in winter) led in turn to tinted and coated glass, external shading and the double-skin façades of recent decades.
Frame a sphere by subdividing the triangular faces of an icosahedron and projecting the points onto the sphere; the triangulated net of short struts spreads loads through the whole surface and encloses the greatest volume for the least material.
full sphere of frequency ν: 30ν² struts, 20ν² triangles, 10ν² + 2 hubs
A saddle surface in which two opposite corners are raised and two lowered is a hyperbolic paraboloid; it contains two families of straight lines, so it can be formed with straight boards and yet has double curvature.
y = k·x·z (or any bilinear patch through four points not in one plane)
A thin curved shell carries load by the membrane forces in its surface, not by bending; so shape it to its loads and supports, and it can span great distances with a thickness of a few centimetres.
span ÷ thickness of a good shell ≈ 400–1000 (an egg: ≈ 100)
A fabric or cable-net roof is stable only if it is prestressed into an anticlastic (saddle) shape, curved upward in one direction and downward in the other, so that wind from either side meets a surface already in tension.
Move ducts, pipes, lifts and escalators out of the building’s core onto its exterior, colour-code them, and let them become the architecture, leaving the interior free and making the plant easy to reach and replace.
Span the whole depth of the building with the structure so that each floor is a single open plate, adaptable to uses that cannot be foreseen.
Pompidou: 48 m clear span between column lines, 13 bays of 12.8 m
Cite this page Chris Paton, “The curtain wall”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/curtain-wall. Text, drawings and models licensed under CC BY-NC 4.0.