Hostile Architecture: The Ethical Problem of Design as a Means of Exclusion


From uncomfortable park benches to unnavigable sidewalks, hostile architecture has emerged worldwide to exclude unhoused individuals from public spaces. Hostile architecture goes against the principles of engineering a communal space. Yet, it persists because it subtly banishes unhoused people from the eyes and minds of communities that fear or are ashamed of them. However, the practice is unethical towards the unhoused and those in the community who experience limited mobility. Ultimately, hostile architecture has never been a sustainable method for solving homelessness, and its use is rooted in harmful bias against unhoused people.

Homelessness is a deep-seated, complex issue that permeates communities worldwide. It is an incredibly intransigent problem, vast in the breadth of people affected and systemic in its institutional and discriminatory roots. Due to these variables, it is impossible to name a quick and effective solution. Thus, as much as efforts have been dedicated to helping the unhoused, similar resources have been dedicated to hiding them. Hostile architecture, also known as defensive or exclusionary design, is one such technique. Most commonly manifesting itself in intentionally placed rails on benches, spikes in alcoves, or convoluted sloping surfaces that prevent sitting or lying comfortably, hostile architecture is a product of civil engineering and city planning. It seeks to exclude unhoused people or other “undesirable” groups from existing in public areas by physically limiting the ways in which the spaces can be used. Though often overlooked by unaffected groups, hostile architecture proves that the same engineering feats that we look to for the beautification and functionalization of our public spaces have the potential to enforce socially discriminatory agendas. As homelessness increases and more and more instances of this architecture crop up worldwide, it is imperative to confront the ethical considerations of implementing exclusionary design. Inherently, hostile architecture goes against the principles of public space by privatizing it, and it is an ineffective and depersonalizing response to the problem of homelessness.

To better understand the ethics of hostile architecture, it is first necessary to conceptualize what makes a space public. City planners and civil engineers are responsible for upholding the equitability of these spaces. Parks, plazas, and streets are typical examples of areas under the control of public agencies that are theoretically open to all. By being deemed public, they should reserve an individual the right “to protest, dissent, make decisions, be heard, [or] be homeless,” as well as commit to “open access, unmediated deliberation, and shared participation [1]”. Of course, this does not make all public land a free-for-all: laws exist to mitigate illegal activities like drug usage, prostitution, or violence [2]. Thus, city planners and civil engineers are not tasked with deterring illicit behavior in cityscapes; lawmakers hold that responsibility. The codes of ethics for both professions state a commitment to “acknowledge the diverse historical, social, and cultural needs of the community” and “understand conscious and unconscious biases […] to better serve a truly inclusive public interest promoting a sense of belonging [3,4]”.

Hostile architecture not only disregards these principles but transforms the act of designing into the act of enforcing by disfiguring what we consider to be public. In this case, there is very little room for lawmakers to draft a code that punishes people for merely existing in public areas, so it is done discreetly through the act of design. It is difficult in most places to criminalize an unhoused individual for sleeping in a park, but it is relatively easy to alter the space so that it is impossible for them to sleep there. One polarizing and publicized example was the Camden Bench, commissioned by a London borough council in 2012 [5]. The Camden Bench, which in essence is a block of concrete decorated with harsh edges, slopes, and a complete lack of horizontal surface, was created with the sole purpose of replacing standard city benches and deterring “illicit” activity; sleeping was determined to fit in this category. Here, the government in Camden could not feasibly deem sleeping a wholly unallowable activity. Still, the designers could circumvent a legal limitation by distorting the space to make it unusable – a trend witnessed in almost every urban environment. Spaces like this are defined as “public” on paper but are privatized through design. These designs are antithetical to the inclusive, communal rights to public space and to the ethical responsibilities that planners and engineers commit to when they initiate the design process.

Most hostile architecture reflects “the priorities of dominant socioeconomic groups, who exercise disproportionate influence over its provision [6].” For example, in San Francisco, residents pooled a few thousand dollars independent of any city commission to heave large boulders on their sidewalks to deter homeless activity [7]. Lines are blurred when people harbor these unconscious biases and feel discomfort, distaste, or fear towards the unhoused, stemming from perceived danger or feelings of guilt. These feelings heighten the tension between the housed and unhoused, increasing their societal separation and prompting this architecture’s persistence. As architectural historian John Ritter put it, “what is hostile to some is defensive to others [8]”. There is an inherent dilemma in claiming hostile architecture as a moral infraction when it creates a perceived benefit for much of society, namely, keeping the source of discomfort out of the line of sight.

However, this begs the question: how comfortable are we with exclusion, and why do we feel that hostile architecture is an appropriate way to go about it? Most people do not feel outward hostility towards people experiencing homelessness, but they prefer them not to be “in their backyard [9]”. This is why hostile architecture often goes without objection: most people can pretend it does not exist purely because it does not directly affect them and is minimalistic by design. Would we still accept its presence if its message were not as easy to ignore? If instead of lining our parks and streets with small bumps and rails, what if we used “Keep Out” signs and sirens? In effect, this would achieve the same goal as current architecture but would require community members to consciously approve of the exclusion or confront their discomfort. Most would be ill at ease with this hypothetical blatancy, so we must forgo the willful ignorance of hostile architecture and address its moral flaws head-on.

Even without the subtlety of the hostile architecture, some individuals would still prefer excluding unhoused people by any means necessary. Many believe that all unhoused individuals threaten society, whether for perceived drug usage, mental health-induced violence, or otherwise [9]. This is a huge debate: around 90 percent of surveyed housed individuals cite mental health issues and substance abuse as the primary reasons for homelessness. In comparison, only 20 to 40 percent of surveyed unhoused individuals listed those reasons [10]. However, even if the overestimation were true, and homelessness were deemed a legitimate threat, hostile architecture would be a morally unacceptable solution; It can cause accessibility issues even for those considered desirable. Whether housed or unhoused, a person with mobility issues will find public space unnavigable when traditionally designed spaces are replaced with more unwieldy pieces, barriers, or blockades [11,12]. For example, the sloped surfaces of the Camden bench would make sitting impossible or even dangerous for older adults or people with disabilities. Likewise, the boulders placed on the sidewalk in San Francisco would complicate the terrain and make the road unnavigable for people with wheelchairs or other aids. Thus, even if the goal of keeping unhoused people out of public spaces is deemed ethically sound, the architecture can cause immense harm and unforeseen consequences for individuals whose societal worth is not in question. At its core, hostile architecture aims to prevent existence in a given space. When the objective is that broad, it can negatively affect more people than intended.

From a resource and goal-driven perspective, hostile architecture is an empty investment that does nothing to eradicate homelessness permanently. If hostile architecture achieves its intended purpose, unhoused people will, granted, have less access to public spaces and thus less incentive to be there. However, they will not disappear from public spheres entirely, as the unhoused have few other places to exist. If keeping them out is the goal, the only effective solution is to dedicate more resources to sheltering and supporting them and thus lower the total number of unhoused individuals long-term. Retrofitting benches, sidewalks, and alcoves with anti-homeless features often requires a significant financial commitment. Iowa City, for example, which is a small town with a population of only 75,000 people, estimated a budget of $150,000 to alter its benches in an anti-homeless manner [13]. Although the cost to increase support measures for the unhoused would likely be more expensive, the benefits immensely outweigh those of implementing hostile architecture. Increasing support for the unhoused benefits both the homeless population and those who would prefer the public spaces to be unoccupied. Attacking homelessness at its source via these measures is a long-lasting solution and is more impactful than the band-aid that is hostile architecture.

Regardless of the stance one takes on unhoused people, hostile architecture should be perceived as more of a hindrance than a benefit. Ultimately, the debate around homelessness will always be contentious because of the intricacy and magnitude of the issue itself. The facets of the problem – whether it be who should be allowed in public and for what reasons, whether the unhoused deserve their fate, or what harm is derived from preventative measures – garner incredibly varied responses. It is naive to believe that one idea could put a true end to this global concern. Still, if society is to advance, we must not continue to endorse technology like hostile architecture. In its place, we can make tangible progress toward more advanced and humane measures.  

By Zoe Nussbaum, Viterbi School of Engineering, University of Southern California

About the Author:

At the time of writing this, Zoe Nussbaum was a rising senior majoring in biomedical engineering, originally hailing from San Diego, CA. On campus, she worked in a research lab studying medical ultrasounds. In her free time, she enjoys watching Jeopardy, taking trips to the beach, and dancing at local studios.


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[12] “Affected Populations,” Hidden Hostility DC. [Online]. Available: [Accessed Mar. 10, 2022].

[13] N. Nielsen, “You’re Not Welcome Here: An Analysis of Anti-Homeless Architecture.” Redefy Stories. [Online]. Available: [Accessed Mar. 10, 2022].

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