This house in Cologne by SMO Architektur adopts two contradicting architectural theories: the open-plan lower floor references Le Corbusier's Plan Libre, while the multi-roomed upper floor follows the principles of Adolf Loos' Raumplan.

Corbusier's Plan Libre, published in the book Vers Une Architecture in 1923, advocated spaces free from walls and partitions, so the living room, dining room and kitchen of this house occupy a single space on the ground floor, surrounded by glass walls that open it out to the garden.

By contrast, the top floor follows Loos' 1930s concept of Raumplan, where each room is designed for a specific purpose, with different proportions and ceiling heights.

Plan Libre and Raumplan are two of the most influential Twentieth Century approaches to domestic architecture yet represent very different approaches to the same problem. Architecture writer Max Risselada compared the two philosophies in his book Raumplan versus Plan Libre, first published in 1987 but recently reissued.

"In this house we unite the two opposing attitudes to architecture to combine the two contrary basic needs of humanity," architect Seyed Mohammad Oreyzi told Dezeen. "On one side is the extrovert, that strives for liberty and the life in nature, and on the other side is the introvert, which yearns for the feeling of security and contemplation."

We've featured a couple of projects influenced by the Raumplan on Dezeen, including a housing development in the Netherlands and an apartment in Australia.

Meanwhile, the open-plan arrangement of the Plan Libre has been adopted as a common style by architects ever since.

White-plastered walls surround the cluster of rectilinear volumes that make up the upper floor, which also features square windows of three different sizes.

A bridge connects the top floor of the house with the street, so residents enter at this level and work their way down rather than up.

See more houses in Germany »

Photography is by Rainer Mader.

Here's a full description of the project from SMO Architektur:

Cloud² represents flexible room designs. It is customized to the client's requests - living areas for the second period of life without children were created, which integrate the charm of a historical building into a new construction.

The project combines two contrary basic needs of humanity. On one side the extrovert, that strives for liberty and the life in the nature and on the other side the introvert, which yearns for the feeling of security and contemplation.

The draft combines two iconic layout-typologies - Adolf Loos' floor plans and the plan Libre Le Corbusier's. It is a hybrid.

First floor plan - click above for larger image and key

As the ground floor at the level of a garden almost consists of one open room, the first floor divides itself into a variety of different proportional bodies, which seem to float over the glassy ground floor like a cloud. The individual disposition of the volumes support the introverted living.

Ground floor plan - click above for larger image and key

The property is located at south of Cologne, in an idyllic environment with lots of greenland, bordering to a historical court. In the immediate neighbourhood there is a small guesthouse, which is a project that was developed in 2005 in cooperation with Oswald Mathias Ungers.

Basement plan - click above for larger image and key

The idea to frame the ground floor maximum open and transparent and to close the first floor on the street level was caused by the difference in height between the property and the street.

Following the idea of transformation to experience the turn of public to private living, the building is accessed by a bridge.

Section - click above for larger image

The entrance-tier is a split-level, which connects the first floor's and the basement's tier. From here on two viewing directions pursue - on the one hand across the open housing space of the ground floor way through the garden and on the other hand upwards to the first floor's rooms. One of two nurseries is in the entrance-tier. On the first floor there is third one in addition with a bathroom und the parent's area, which is designed as a suite.

Front elevation - click above for larger image

From the entrance you can see an even flight of stairs, which is exactly set in the access route down to the bathed in light ground floor. At the longitudinal side of the room there is the kitchen- and the dining area, opposite to the living area. On the rearward side of the street the closed library affiliates itself with an entry to a courtyard.

Side elevation - click above for larger image

The ground floor tier is characterized by spatial generosity and transparency, which creates a tight connection between outdoor space and internal space. The flagrant facade post and its irregularly rhythm and the thin solid steel-pillars on which the whole first floor bears generate a very light disbanded room border.

Rear elevation - click above for larger image

The first floor's rooms formally push themselves down and cause different ceiling heights. This enables visual connections from the inside to the outside and creates there with purposeful spatial atmosphere.

Three different square window formats perforate the first floor's introverted rooms. The disposal of the windows produces an individual light enactment of every room and avoids the range of vision to the neighbours. Another feature is the original roof landscape, which gives rise to a stepped water garden in the form of cascades when it rains.

Side elevation - click above for larger image

Project status: Completed 2012
Team: smo architektur
Designer: S M Oreyzi
Area: 380 m2
Location: Cologne / Germany
Costs: 780.000 €