Published in 3/2025 - Suburbia

Article

The Promise of Medium-Density Housing

Text Aleksandra Zarek, Panu Lehtovuori Images Asuma 2.0

A city that provides room for both people and nature might be found somewhere between apartment blocks and detached houses. The Asuma research project gives a new benchmark for optimal urban density.

In recent years, a key aim in housing construction in growing Finnish cities has been to increase density. Be it an inner city renewal, a re-use of harbours or new suburban sites, relatively high-rise multi-storey apartment blocks dominate the field, with occasional towers as the sign of a new decade. The market-led provision of high-rise residential typologies comes at the cost of both environmental and social sustainability. Public spaces in and around such developments lack communal cohesion, emptying the promise of ”new urbanity” as well as the possibility of accommodating multi-species solutions.

In terms of housing quality, the new status quo has normalised substandard and overpriced apartments. Such units are characterised by squeezed square footages, single-sided orientation and extremely deep yet narrow floor layouts. The shared facilities of residents, such as yards and storage spaces, are minimal. What used to be a default living standard in housing design and neighbourhood planning in the past is now viewed as luxury.

Parallel to aiming for high densities and a big scale in urban projects, the planning and construction of mono-functional detached or semi-detached single-family dwelling areas have continued in peripheral greenfield locations. Environmentally problematic and car-centric, most single-family housing zones are devoid of community facilities, shared services and equitable mobility options.

Led by Panu Lehtovuori at Tampere University and co-funded by Ara, the Housing Finance and Development Centre of Finland, the recent Asuma 2.0 project took a critical and creative look at the current rigid division between the dense and sparse modes of city-making. Through the research-by-design method, we developed proposals for low-rise medium-density housing communities. Learning through designing units, blocks and beyond, the project strives to find intermediate community- and nature-focused living solutions positioned between profit-oriented high-rise schemes and loosely populated areas dominated by detached houses.

Four Scales of Design and Planning

The word asuma (living place, residence) in the project’s name is a tribute to the long career of councillor and architect Olli Lehtovuori, an advocate for diversifying housing typologies. Besides his theoretical and practical work and alongside other ongoing discussions, an important starting point for the project included the Spacematrix toolkit, developed by researchers Meta Berghauser Pont and Per Haupt, that establishes a holistic set of indicators for different aspects of urban density and related typological opportunities and environmental qualities.

Following the Spacematrix concepts, we assessed the urban environment in different scales through coverage (building footprint), building intensity (floor-area ratio), network density (characteristic of the street layout) and the tare of the urban structure (the ”empty weight” of interim land-uses that have to be counted when the scale of analysis grows). 

The research revealed that a medium-density city enables diverse combinations of different housing types. The medium-density urban structure combines the characteristics of low and dense construction, an urban street network and high-quality public and green spaces with the goal of an urban area intensity of 0.3–0.6, leading to plot intensities of above 0.5 but typically below 1.0. In our study, we saw that plot coverage usually is, in turn, approximately 0.3–0.4, which means that about half of the land area beyond necessary access routes is available for a variety of other uses. The inclusion of biodiversity to restore the relationship of city dwellers with the natural environment is thus possible.

Although building intensity is an essential criterion for medium-dense urbanism, the intensity of use – for example, how much floor area there is per resident – is also important for the social life and economic viability of new projects and neighbourhoods. For this reason, flexible housing design that adapts to specific needs is an essential part of the medium-density concept. 

Using a housing unit as its starting point, Asuma showcases an urban planning tool to design the residential block, neighbourhood, and contextual location within cities. This multi-scale approach ensures the cohesion of urban tissue and a holistic overview of spatial planning, indispensable for a balanced densification strategy.

Housing Unit as a Starting Point

The basic housing unit consists of one apartment, which can be subdivided into two or more independent ones with separate entrances, if necessary, and connected to other units. The possibility of varying the unit floor plans without changing the main dimensions of the building is another vital component of the approach.

Simplicity in the design of a unit promotes low costs and an ease of construction for wide-scale applications. Low-carbon living is not based solely on construction methods and material choices, but also on multi-generational life-cycle sustainability and adaptable living options. 

Divisibility is based on organising the unit’s spaces into sections that can be either interconnected or separated. Internal adaptability means that the shape, openings and grouping of fixed spaces within these sections allow for various room layouts and the connecting of rooms between two apartments. Flexibility in different life stages and living situations is also important from an economic perspective to promote financial liquidity. A ”switchable” room is showcased to accommodate both the living and revenue needs of the inhabitants, or the room can be rented out or sold to a neighbour.

There are two basic types of units. Row units create linear building masses, while corner units are placed to connect blocks at perpendicular junctions. Flexibility is built in through divisibility and internal adaptability. 

A Lesson in Diversity

The Asuma block is an area of residential construction, delimited by streets and zones reserved for a wide range of activities, with a recognisable shape and a clear relationship to outer streets.  The diversification of individual block options depends on a series of choices. The selection of unit types and their clustering allows for row housing with open or closed corners, small apartment blocks with deck access and occasional semi-detached houses. All of the building structures are low-rise, mostly not exceeding three stories in height, to allow for an intimate, human scale. 

Shared common spaces can be in a separate building facing an inner courtyard or placed on the ground level at street corners, doubling as commercial fronts for the outer urban realm. The positioning of individual entrances and private yards depends on the desired social character. The important feature is a mix of these elements facing either inner courtyards or outer streets to establish both neighbourly and external urban realm connections.

The architectural articulation of each block should showcase design simplicity but not monotony. This can be achieved through the expressing of different roof lines in different buildings, roof terraces or balconies, or feature corners of emphasised mass. Good permeability through multiple routes, as well as short walking distances and entrances to residential and common areas from inner courtyards stimulate social interactions and address problems of urban loneliness. High-quality circulation spaces, where required (gallery access in apartment blocks), offer another platform for social cohesion. The management of semi-public spaces should also be agreed upon in a joint strategy between different housing companies from the outset of a design process. Finally, 30% of each block area is dedicated to a biodiversity zone.

Although a multitude of potential basic housing units were proposed, the list of possibilities is by no means exhaustive. It must also be emphasised that although the proposed unit designs are fully implementable practical solutions that are in compliance with current local legislation, they should not be treated as set-in-stone manuals. Similarly, although several possibilities of clustering the units into buildings and then blocks are presented, the number of permutations can grow almost infinitely. Using them as evolving theoretical examples that can be applied to initiate concrete design and planning solutions offers a much more sensible, flexible and liberating way of approaching the discussion on the production of housing and cities. The main point of the project is to show that a medium-density city enables distinct urban qualities and a wide range of combinations of different house types and block shapes.

Flexible Urban Neighbourhoods

In urban planning, complexity increases rapidly with the scale. This is the reason why the Asuma project studied the housing unit in detail and discussed the elements of urban blocks at some length. In the neighbourhood scale, many contextual and historical issues become decisive. Thus, we are not proposing any rigid formula for ideal medium-density neighbourhoods.

Having studied existing medium-dense neighbourhoods and experimented with Asuma housing types, we came to the conclusion that a good starting point for the neighbourhood design is a relatively low street network density, which allows large blocks, typically 120 x 120 metres or more. The large blocks should be permeable, though, so that the networks for walking and cycling as well as the green connections are dense, while the car network remains sparse. This logic goes somewhat against the argument, inherited from Jane Jacobs, that a dense street network is best for social life and business opportunities. In the contemporary digital world, it is not very realistic to achieve fully active street fronts beyond city centres. However, few streets in the medium-dense urban areas may achieve an urban quality and service provision by combining good accessibility through all modes of transport and by creatively combining both commercial and non-profit services, managed flexibly together.

Furthermore, we realised that, in the urban tissue, there are four possible and fundamentally different ways to locate the biodiversity zone in respect to streets and buildings, leading to qualitatively different options for urban design and public space. The greenery can constitute small-scale alternative networks (viherverkko) or larger nature zones (vihervyöt). It can also be situated inside larger blocks to combine social and ecological aims (vihersydän). Finally, biodiversity reserves can follow streets to create a new neighbourhood typology of wild and free-form boulevards (viherkadut).

Rethinking Suburban Space

While Asuma principles and solutions fit in a wide variety of urban contexts, their most imminent application will likely be in suburban renewal and repurposing. The low-rise approach and possibilities to address both small-scale infill and neighbourhood-level tasks make Asuma a potential toolbox for the near-future changes in areas such as Helsinki’s and Turku’s postwar suburban belts and the Tampere region’s many growing municipalities. Importantly, the cost-efficient and flexible Asuma ideas may also work in smaller towns and locations characterised by uncertain development perspectives.

 In conclusion, the results of the Asuma project confirm the continued importance of careful housing design and progressive urban planning. Well-lit apartments, control over your own living space and the proximity to nature are no longer offered in market-driven city-making.

On the other hand, the project brought new themes to the agenda. Asuma shows that the systematic inclusion of 30% of urban land for biodiversity is not only possible but also socially and economically beneficial, as versatile greenery works for both human and non-human users, building multi-species wellbeing and sustaining the value of  housing. In this sense, Asuma offers a benchmark for the ongoing debate on optimal urban densities. Another important finding is the importance of flexibility and adaptability in housing design in order to address changing demographics, challenging economic situations and a better intensity of use over time.

We strongly believe that low-rise medium-density urbanism has much to offer to regenerative and recursive urbanism, locally rooted city-making that simultaneously improves both the social and the ecological balance. For planners, Asuma gives a softer and subtler tool for rethinking and renewing suburban spaces and environments – the actual value of which we are just beginning to recognise. ↙

ALEKSANDRA ZAREK is a practising architect and a doctoral researcher at the School of Architecture at Tampere University.

PANU LEHTOVUORI is the professor of planning theory at the School of Architecture at Tampere University.

The writers wish to thank Ara’s Vesa Ijäs and Vilja Kamppila, all stakeholders that supported the Asuma project, as well as the whole research team that includes also Markku Norvasuo, Kimmo Rönkä and Jyrki Tarpio. The research report can be downloaded online.