Since columns carry the floors, partitions can be placed wherever the use requires, independent of the structure and different on every storey.
In a masonry house the walls of each floor must stand on the walls below, so the plan repeats from basement to attic. In the free plan the regular grid of columns is one system and the partitions another: curved bathroom walls, freestanding screens and ramps can pass the columns at any angle. Mies van der Rohe’s Barcelona Pavilion (1929) takes the idea furthest, setting slabs of onyx and marble loose beneath a roof carried by eight cruciform steel columns.
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)
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
In a framed building the columns and beams carry every load; the outer wall can be reduced to a light cladding hung on the frame, floor by floor, and need grow no thicker as the building rises.
load-bearing wall: thickness grows with height · frame: cladding thickness constant
Build the house as a standard skeleton of flat concrete slabs, a few columns set back from the slab edges, and a stair; everything else (walls, windows, partitions) is infill that can be placed freely.
3 slabs + 6 columns + 1 stair
With a concrete frame, a house should stand on pilotis, have a free plan and a free façade, be lit by horizontal ribbon windows, and carry a garden on its flat roof.
pilotis · free plan · free façade · ribbon window · roof garden
Cite this page Chris Paton, “The free plan”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/free-plan. Text, drawings and models licensed under CC BY-NC 4.0.