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Competition: Affordable Housing Challenge, Cambodia

Building Trust International has launched an open contest to design a 3,000-unit affordable housing development in Phnom Penh, Cambodia (Deadline: 15 July)

Open to architects, designers and engineers, the single-stage competition seeks a masterplan and sustainable housing concept for low-income workers within the capital city’s rapidly growing Special Economic Zone.

The project, backed by the United Nations Development Programme and the Phnom Penh Special Economic Zone (PPSEZ), aims to boost the quality of life of local residents and surrounding communities by delivering new units at a cost of $16,000 each. The winners will share a $40,000 prize fund and potentially see their designs built.

Phnom Penh Special Economic Zone

Phnom Penh Special Economic Zone

Phnom Penh Special Economic Zone

According to the brief: ‘The aim of this competition is to design modern, affordable homes for the workers in and nearby PPSEZ. The design should have a sensitivity to the local culture and tropical surroundings and where possible provide a sustainable solution that enhances the local architectural tradition, in which locally sourced renewable resources are used to provide natural temperature and humidity regulation.

‘The houses should be designed for families, young couples with optional design elements for multiple or larger groups. As a total of 3,000 units are to be designed within the housing community, please include an overall masterplan of how the units will be arranged. This community planning should include supporting facilities that meet the basic needs of residents, such as children’s daycare, shops, and public/green space.’

Phnom Penh is the capital of Cambodia and the country’s main economic, industrial, and cultural centre. In recent years it has witnessed a surge in manufacturing activity which has brought large numbers of low-income workers to the city.

Phnom Penh Special Economic Zone

Phnom Penh Special Economic Zone

Phnom Penh Special Economic Zone

The PPSEZ was set up 12 years ago on the outskirts of the city and is today home to more than 88 companies which benefit from a range of government support programmes, reduced bureaucratic requirements and high-tech infrastructure.

The latest competition focuses on a 70,000㎡ riverside site within PPSEZ’s third phase which will be the latest part of the development and is currently being marketed to interested companies.

Submissions must feature a standard housing unit – which will be sold for a maximum of $16,000 – featuring a bedroom, living room, kitchen, and toilet. Concepts will be expected to maximise space and provide access to fire exits, ventilation and natural light.

The overall winners, to be announced 1 September, will receive a $20,000 prize while four additional prizes worth $5,000 each will also be awarded.

How to apply


The registration deadline is 15 July and submissions must be completed by 1 August.

Contact details


Visit the competition website for more information

Q&A with David Cole

The director of Building Trust international discusses his ambitions for the contest

David Cole

David Cole

David Cole

Why are your holding an open international competition for affordable housing solutions for low-income workers in Phnom Penh, Cambodia?

We want to find new solutions to a housing crisis that is not unique to Cambodia, increased urbanisation and pressure on cities is a global problem. However, with this site in Phnom Penh we have an opportunity to look at one area of the city that is pretty autonomous, producing its own solar power and treating its own water supply in a sustainable way, It also has a range of employment opportunities which are set to grow and will increase the local population. We think that this offers a unique chance to create a model for sustainable medium/high-density housing solution that can meet the UN sustainable development goals and perhaps can have wider ripple effects on setting a bar for other local housing development.

What is your vision for how the new housing?

We are very interested in innovation in this field, with the economies of scale we have a real chance to try some new things not only with programme and layering of activities, but also with materials and even with the way in which we plan to build. At the heart of any winning proposal will be a real emphasis on sustainability issues, and while this term has lost some of its edge over the last decade we hope that contestants will strive towards submissions that have a strong focus on environmental, social and economic benefits to the community and wider area.

What sort of architects and designers are you hoping will apply?

One of the great things about this challenge is that it is open to anyone. Traditionally we split the competition entrants into students and professionals but this time we have left it open. It’s a level playing field, we also don’t mind if people submit multiple entries. It’s a chance for a graduate to submit an idea alongside a large practice that has been working in the field for many years. Aside from the cash prize, we have a strong commitment from our partners to work up the detailed design and build the winning design. This is a good springboard for any architecture firm or individual into further social housing and affordable housing in developing countries. It’s also a great worthwhile project which has the potential to help thousands of families out of rent traps and on a path to a more secure future that would be lost to them otherwise. The real objective here is to show how sustainable design can have a long-lasting beneficial impact.

Which other design opportunities are on the horizon and how will the architects/designers be procured?

This is the eighth Building Trust Design challenge in as many years and we find them great ways for both clients to find exciting new ideas and those that take part to find work in the field of humanitarian or social impact design. The back catalog of projects inspires others and we’ve had countless entrants who have not won the actual challenge contacted afterwards to work on other projects as a result of the exposure of taking part. We hope that the scale of the challenges can continue to grow and entice people to use design as a tool for real positive change.

Are there any other innovative affordable housing projects you have been impressed by?

There are quite a few affordable housing projects that I admire, but none that really fall into this category, ie under $17,000 per unit. I personally will be looking for environmentally sensitive solutions to overheating that allow families to invest and develop the housing after its completion – how they can personalise and adapt designs to suit their lifestyles and potentially add further value.

Courtyard House case study: Q&A with Jess Koller Lumley and Alexander Koller

Jess Koller Lumley and Alexander Koller

Jess Koller Lumley and Alexander Koller

Jess Koller Lumley and Alexander Koller

The co-founders of Lumley & Koller discuss lessons learned designing the winning scheme in an earlier Building Trust International contest for new homes in Cambodia

How did your competition-winning scheme provide affordable housing tailored to Cambodia’s requirements?

In all honesty, we are not sure if it did. Architecture, or the shelter of a home, is but one aspect of the multitudinous requirements for affordable housing in Cambodia. The provisions for roads, sewage, waste disposal and other public services are equally, maybe more, critical. These were beyond the scope or control of the competition.

Our intention was to design a dwelling that would be familiar to Cambodians and easy to build with broadly traditional materials, something that could feel like a home rather than an imposed foreign experiment. The site was very tight at 5x12m and the proposed scheme was very basic and premised on the vernacular Cambodian dwelling of a single family room raised on stilts - to many Cambodians, a home is not a home unless it is raised up. To this we incorporated cooking and sanitary areas by way of a bridge over a small courtyard garden, this being a model long-used in neighbouring Vietnam and Southern China. To an outside eye, or Western perspective, one could say that it looks like a shack on sticks.

Courtyard House by Lumley & Koller

Courtyard House by Lumley & Koller

Courtyard House by Lumley & Koller

Which architectural, material, visual and other methods did you harness in your design?

The most important aspect of the Courtyard House, was, as the name suggests, its courtyard garden which physically and visually connects the ground and raised living areas, as well as providing natural light and ventilation to all areas within the site constrictions.

In terms of layout, many Cambodian families like to sleep in one room, so the living area of the house was designed with alcoves and a outdoor entrance deck overlooking the street and the bridge out to the back deck, the idea being that it could provide a variety of spaces that could also be screened off if needed for a modicum of privacy – such as for adolescent daughters which is customary. We adopted traditional methods for shade, ventilation and rain protection: deep overhanging eaves, split bamboo and palm leaf matting for the walls and floors and by raising the living area up on stilts for protection against floods and snakes. The bamboo and palm leaf matting provide a ready-made warm attractive texture. The open shady spaces created by the stilts house hammocks, bikes etc and are often used for familial and neighbourly gathering.

New to the idea of a traditional Cambodian dwelling was the proposal for a brick party wall to one side of the house. This was proposed in the context of the tight site, as fire protection and to allow the Courtyard House to be configured as a series of terraced or semi-detached houses.

Courtyard House by Lumley & Koller

Courtyard House by Lumley & Koller

Courtyard House by Lumley & Koller

What advice would you have to contest participants on designing new affordable homes for Phnom Penh Special Economic Zone?

Cambodia is undergoing a revolution, not just of the type that one hears about in the news, involving street protests and contested elections but a social and economic one with a rapidly increasing density of habitation. The cataclysm of Khmer Rouge rule with its depopulation of the cities and subsequent chaotic re-population was never properly addressed in urbanistic terms. Phnom Penh instead has rather been taken over by greedy developers on the one hand and the unregulated growth of slums on the other.

It can be hard to think of architectural merit in places where the neighbourhood struggles to keep their children away from playing in dank, toxic pools that make them chronically ill. Ignoring this, or on the assumption that this is changing, one can think the answer partially lies in natural materials and traditional working methods. However a keenly felt deficiency is the scarcity of timber, a result of years of illegal exploitation of the Cambodian forests and dramatically rising prices. Concrete, brick and steel are now in many ways much more ‘sustainable’, provide easy solutions for sound, and are opted for by the more affluent Cambodians. It would, however, seem rather counterintuitive to abandon the wisdom and aesthetic awareness of centuries of building; perhaps though the density requires this.

The decision for the designer is whether to remain within a Cambodian (or generally Southeast Asian) aesthetic framework. Another, is how to consider domestic life. Cambodians are still family-oriented in an extended rather than nuclear sense. Can an urban and dwelling solution be found that could accommodate and facilitate this? The answer can only be partial and it must be honest in its limitations. Good architecture cannot solve the problems of the new Cambodia but bad architecture could make them a great deal worse.