1.Pilotis

2.Free Plan

3.Free Facade

4.Horizontal Window

5.Roof Garden

1. The supports. To solve a problem scientifically means in the first place to distinguish between its elements. Hence in the case of a building a distinction can immediately be made between the supporting and the non- supporting elements. The earlier foundations, on which the building rested without a mathematical check, are replaced by individual foundations and the walls by individual supports. Both supports and support foundations are precisely calculated according to the burdens they are called upon to carry. These supports are spaced out at specific, equal intervals, with no thought for the interior arrangement of the building. They rise directly from the floor to 3, 4, 6, etc. metres and elevate the ground floor. The rooms are thereby removed from the dampness of the soil; they have light and air; the building plot is left to the garden, which consequently passes under the house. The same area is also gained on the flat roof.

2. The free designing of the ground- plan. The support system carries the intermediate ceilings and rises up to the roof. The interior walls may be placed wherever required, each floor being entirely independent of the rest. There are no longer any supporting walls but only membranes of any thickness required. The result of this is absolute freedom in designing the ground- plan; that is to say, free utilization of the available means, which makes it easy to offset the rather high cost of reinforced concrete construction.

3. Free design of the facade. By projecting the floor beyond the supporting pillars, like a balcony all round the building, the whole facade is extended beyond the supporting construction. It thereby loses its supportive quality and the windows may be extended to any length at will, without any direct relationship to the interior division. A window may just as well be 10 metres long for a dwelling house as 200 metres for a palatial building (our design for the League of Nations building in Geneva). The facade may thus be designed freely.

4. The horizontal window. Together with the intermediate ceilings the supports form rectangular openings in the facade through which light and air enter copiously. The window extends from support to support and thus becomes a horizontal window. Stilted vertical windows consequently disappear, as do unpleasant mullions. In this way, rooms are equably lit from wall to wall. Experiments have shown that a room thus lit has an eight times stronger illumination than the same room lit by vertical windows with the same window area.

5. The roof gardens. The flat roof demands in the first place systematic utilization for domestic purposes: roof terrace, roof garden. On the other hand, the reinforced concrete demands protection against changing temperatures. Overactivity on the part of the reinforced concrete is prevented by the maintenance of a constant humidity on the roof concrete. The roof terrace satisfies both demands (a rain- dampened layer of sand covered with concrete slabs with lawns in the interstices; the earth of the flowerbeds in direct contact with the layer of sand). In this way the rain water will flow off extremely slowly. Waste pipes in the interior of the building. Thus a latent humidity will remain continually on the roof skin. The roof gardens will display highly luxuriant vegetation. Shrubs and even small trees up to 3 or 4 metres tall can be planted.In this way the roof garden will become the most favoured place in the building. In general, roof gardens mean to a city the recovery of all the built- up area.

These points were illustrated best in Le Corbusier's domestic architecture. Le Corbusier's first attempt to deal with the problem of mass housing was Maisons Citrohan, designed in 1920-1922. All parts of the house are united by a spatial continuum, while the open space created by the pilotis and the flat roof increase the otherwise small available area.Citrohan introduced ideas of Le Corbusier's '5 Points of New Architecture': the building raised off the ground on pilotis, which 'free' the ground for vehicular circulation and for services. The roof-garden or terrace, which is clearly established in the Citrohan projects as a component of private, domestic space. The prototype of a single-family unit, which was later modified to a module within a collective building, for example the basic units of the Immeuble-villa.

Maisons Citrohan