Low-Rise Housing Typology
The dynamic population growth that took place in the 20th century was accompanied by a process of rapid urbanization, which also left traces in housing typologies. Furthermore, two world wars led to social disruption and the erosion of entire cityscapes, which had consequences for the forms of dwelling that had grown so gradually beforehand. In other words, trends and fashions exist rather than an endless status quo.
Socio-cultural influences play an important role alongside economic factors in defining the vague term “dwelling”. The ageing of the population, emancipation and migration are changing our concepts of housing. It no longer has to cater exclusively for families, and the supply and demand of traditional dwelling types are obviously affected by this. In addition, the free play of market forces is now regulated by the state. Housing types do not die out, though: they are adapted and transformed to meet different circumstances.
In the following paper, this outline of types of low-rise housing will focus on individual
owner-occupied forms on the one hand and concepts for higher-density developments on the other. Hybrid forms are the rule. For example, a single-family house can accommodate a second family in a self-contained flat without becoming a semi-detached type.
Typologically, small housing structures are determined largely by three main parameters: house, street and garden. Housing structures on large sites with their own gardens are referred to as detached houses. The original characteristic of this type is the generous outdoor space in which it stands. This was meant to provide protection against overlooking. Forerunners of this type were the Renaissance summer villas on the latifundia of Italian aristocratic families – houses like the Villa Rotunda by Andrea Palladio, which in turn were inspired by Graeco-Roman models. The free view on all four sides was a symbol of the power of those who dared to leave the protection of city walls and live an untroubled life in the midst of nature. A notable contribution to this type can also be found in the Prairie Houses of Frank Lloyd Wright and his pupils.
Detached houses with a high-quality design are a minority, however, because land has become a limited commodity. What’s more, there is increasing public awareness that land needs to be protected. For the large majority of those who wish to build a home for themselves, the pared-down version of this ideal – a house in the suburbs – remains the dream. Often, though, this takes the form of a poorer quality mass-produced object squeezed on to a tight site. Criticism is also justified, because the service costs are usually a negative factor for local authorities. High development costs for roads and sewers, not to mention the urban sprawl that consumes regional cultural landscapes, all speak against this type.
A first step in the direction of increasing the density of large-area housing developments occurs through the division of a bigger site
into two parts, where the two parties share a common roof; i.e. the semi-detached house.
An annex in the form of a second dwelling re-duces the independence of the two halves: it is no longer possible to walk all round one’s site, and an external facade is lost in the pro-cess. As a result, the daylighting of the rooms along the party wall and the orientation of the building are restricted. Furthermore, the fire and noise that could be transmitted through the separating membrane necessitate a fireproof, sound-insulating barrier. There are certain advantages that compensate for the additional outlay, however. For example, both owners benefit from not having to purchase additional land in order to observe the distance normally required between two buildings. Savings can also be achieved in primary energy costs in comparison to detached houses, since the wall between the two halves of the building is heated on both sides.
In the case of terraced houses lined up in a row, the road would seem to be the dominant parameter. In many terraced-house developments, one doesn’t even see a garden. A clear front and back exist, with noise on the street face and with a quiet garden face; and there are end houses in the road or in an individual row; but the design of the intermediate units cannot easily be orchestrated differently, since they possess only two facades. Projections and recesses in a serrated layout can make the row seem visually unbalanced and have a negative effect in terms of energy, since the area of the outer skin will be greater.
The terraced house type can be found throughout history, but the wide range of modern variations on this form would be inconceivable without the development of experimental prototypes in the model estates of the early Modern Movement.
In planning owner-occupied terraced houses, the individual wishes of clients can push their way into the foreground in an unwelcome manner and conflict with the proposed design form. On the other hand, in terraced houses erected for rented occupation, similar pitfalls can occur to those encountered in multi-storey housing. The overall form should not be watered down; at the same time, a pleasant domestic environment must be created. Developments where there is no scope to build a home with which one can identify will later be subject to vandalism or wild building-market assemblage.
Bedroom and living areas are commonly located on different floors. The width, form and topography of the site determine the parameters for access and circulation. Longitudinal staircases are generally favoured for narrow plots of land. The wider the site, the freer the choice of vertical circulation will be. Terraced houses on a sloping site can be developed as split-level types with a series of spatial hierarchies between street and garden level.
With the migration of homeowners from the country back to the city centre, urban forms of the narrow terraced house type have increasingly manifested themselves since about the 1980s – so-called town houses with up to four full storeys and a small garden.
The housing types described up to now have been distinguished by their orientation to the outside in order to gain light and enjoy views. Austrian architect Roland Rainer remarked that “a withdrawal from the outer world can be achieved only through a constructional separation of public and private open
spaces”. The arrangement of a number of structures about an open central space could be understood under the general heading of “housing with courtyards”. A distinct characteristic of such developments is their intro-verted nature: there are few openings to the outside; and the courtyard also forms the central access route. As a rule, structures of this kind are single-storey buildings.
The layout of the courtyards depends on the macroclimate and especially insolation. Courtyards in hot desert regions are usually dimensioned to prevent excessive heating of the outer walls by the sun and to allow cooling streams of convective air to be created – sometimes with the aid of pools of water. In northern latitudes, courtyards have to be designed so that the south face receives sunlight for as long as possible. The west and east faces should be generously glazed to benefit all year round from the microclimatic thermal buffer formed by the open space. The main courtyard house types are described below.
The origins of the atrium-house extend far back in history. In all cases, the underlying idea was to secure protection against enemies and inclement weather. Today, the atrium house is scarcely encountered in its original form, with rooms laid out on all sides of a central courtyard, since the weather conditions in northern latitudes restrict a comfortable line of access exclusively via this open space. In the “honeycomb” estates planned by the architects Neidhardt, Mittel and Ruff around 1930, a corridor zone was therefore laid out around the courtyard. In variations of this kind, proper daylighting of the adjoining rooms can be effected solely via the outer walls or via roof lights. A glazed roof over the courtyard that can be opened for ventilation purposes allows the access function of this space to be maintained, but the orientation of the private rooms must inevitably be to the outside because of the hall-like climatic conditions in the internal circulation zone. Scope for extending atrium types of this kind over a larger area is therefore limited.
Single-storey atrium houses surrounded on three sides by neighbouring buildings need an almost square site at least 15 ≈ 15 metres in extent, and the orientation of the layout on all sides to the courtyard calls for great care in its design. To avoid mutual disturbance, the size of this space should also reflect the number of users. An atrium for a family of four should be not less than 40 m2 in area.
The advantages of living entirely at ground level moved some of the early representatives of the Modern Movement to investigate low-rise dwelling forms like those on which the garden-city idea is based. Walter Gropius criticized these goals, claiming that they were unsuitable for mass housing, since the single-storey form meant “the negation and dissolution of the city”. Countering this argument, Ludwig Hilbersheimer contended that everyone must be to allowed to choose the type of dwelling he or she preferred. Low-rise housing with gardens is better for families with children, whereas couples without children, or single persons tend to prefer living in high-rise structures with communal facilities. He therefore called for mixed housing developments with high- and low-rise structures.
The mutual interference of adjoining houses led both architects to undertake trials with elongated housing strips at right angles to the road and with south-facing gardens in front. Both Gropius and Hilbersheimer then went on to develop dwellings with L-shaped floor plans, access to which was from the north side, with the living tract in the south-facing wing. While the kitchen is oriented to the road to the north, the bedrooms are lined up along a short corridor in the adjoining eastern wing.
The L-shaped Type E house, dating from 1931, became a pioneering form for all further courtyard-garden houses, and in the 1960s, the boom this type experienced extended as far as Scandinavia. The courtyard facades should be oriented towards the south-east or south-west if possible. L-shaped courtyard houses can be linked serially to form chains of dwellings.
Perhaps the most interesting courtyard dwelling type is the patio house, which is a response to narrow, elongated building sites. The origins of this form can be found in the Spanish-speaking world. The patio was probably a development of Moorish residential courtyards. The sites, on which a number of families lived in a clan-like relationship, were sometimes as much as 30 metres deep and only a few metres wide at the narrowest points. This inevitably led to elongated corridors. Because of the strong Mediterranean sun, the courtyard areas were kept relatively small. The patio type – originally laid out on two floors, since greater shading in the small yards was welcome – experienced a significant boost with the revitalization of the Spanish colonial style in California, where it was advocated by the immigrant Austrian architects Rudolf Schindler and Richard Neutra. Following this lead, American architects also began to plan houses with a number of patios that took account of functional divisions. In the “dual-cell” type – a term coined by Marcel Breuer – the living and sleeping areas are laid out in two separate tracts, with a linking section between, forming a U- or H-shaped plan.
In the Netherlands, the influence exerted by Spain from the 16th century onwards also resulted in deep housing sites with small “hofjes”. In 1990, Adriaan Geuze made reference to this canal- or “grachten-” house type in the master plan he drew up for the former harbour Borneo-Sporenburg in Amsterdam.
The decisive factor for patio houses in northern latitudes, however, is an optimum exploitation of daylight by means of roof lights, loggias cut into the volume of the building, or sunken courtyards to bring light into areas it would otherwise be difficult to develop. The effectiveness of the patio house is revealed above all on tight sites. Its ideal role lies in filling gaps between buildings.
Nothing is so changeable as change itself. The range of housing types in the future, for example, will continue to be influenced by the conditions that shape living patterns. The urgent objectives of the 21st century drastically to alter energy paradigms in view of migration and the threat of climate change will certainly lead to interesting new variations in the form of higher-density housing types.