Infill Housing

Definition, Types, and Forms

Infill housing has a number of definitions and is used in a variety of ways. In its broadest sense, infill housing simply means any degree of residential intensification, whether that means filling in vacant spaces or the redevelopment of entire blocks and neighborhoods. Thus, a useful distinction can be made between infill housing as a type and infill housing as a process. As a type, infill housing takes many different forms, depending to a significant extent on a society's expectations around existing housing norms. For example, infill housing in Australia and Asia will look very different from infill housing in Europe, where residential densities are traditionally much higher. At the lower density end of the housing spectrum, infill housing often means subdividing an existing suburban section or lot and building an additional house where the garden used to be. This essentially doubles the number of houses on a given section. Alternatively, the original house may be demolished altogether to make way for two or more new houses or apartments which may contribute to even higher housing densities (see Figure 1).

In a qualitative sense, infill housing tends to involve changes in outdoor-indoor space ratios where the latter starts to exceed the former. It is often the result of a zoning change that allows for smaller minimum section or lot sizes, and as a result, it can be quite uncoordinated and not necessarily well pegged to the provision of other services and facilities in a particular area. Infilling may or may not be undertaken in conjunction with other policies, such as the “mixed use” of light commercial, retail, and residential.

Figure 1 Some of the More Common “Low-Density” Types of Infill Housing

Infill housing tends to be less intense than medium-density housing, which almost always involves “terrace housing” or “apartment-style living” and different management processes, such as a corporate body.

Advantages

Some assumptions driving infill housing are that it makes good use of urban land and contributes to the building of a higher density and supposedly more “sustainable” city. Higher density cities are thought to be more sustainable because they prevent urban sprawl onto agricultural land and natural habitats at the urban periphery, make public transport and other service provisions more economically viable, thus improving equity of access, make good use of hard infrastructure, and are socially vibrant and foster an informal surveillance that arises from having more people on the streets. Infill housing, which tends to have vastly smaller low-maintenance outdoor space, suits some people's housing needs very well.

Disadvantages and Debates

There is also some debate as to whether urban consolidation generally, and infill housing more specifically, can succeed in many cities. Because infill housing can be poorly coordinated, many of the supposed benefits of such development are left to chance or the market. For example, higher residential densities do not automatically lead to better public transport provision. The disadvantages of infilling for local residents may be considerable. Service provision is not necessarily more equitable in a compact city and may, in fact, place additional strain on existing services. Similarly, infill housing may place extra pressure on existing infrastructure like roads, sewers, and green spaces. Social “vibrancy” can be experienced as “noise” in the “concrete jungle.” Cities that have imposed growth boundaries may experience problems with housing [Page 398]affordability, and increasing residential density does not necessarily lead to greater population densities.

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