Notable points from the Green Building Tech Workshop

This post collects all the knowledge that we collected during our 2019-11-24 “Green Building Tech” workshop in Brussels. (As promised, I will delete the audio recording now. It was just our way to note all the contributions without a pen … .)

I roughly group together the contributons by topic. They will further inform our to-be-published open source document about green living, so this is not the final form. At this point, big thanks already to all our contributors: Bernardo, Clémentine, Olivier, @Alberto, @Ilaria, @Malcolm, and myself.


1. Techniques for architecture and construction
2. Building features and space utilization
3. Dealing with rules and laws
4. The role of lifestyle and behaviors
5. About communal living in more general

1. Techniques for architecture and construction

  • Exploring a proposal before it’s built. Architects to models a lot (actual physical models, not just 3D models). Others do a lot of discussions with potential users, to explore how they react to their design ideas.

  • Exploring construction innovations on a small scale. For construction innovations aimed at large-scale application, architecture studios (like that of Renzo Piano) combine architecture with research. That however cannot really be pulled off for a single community building. There are also software packages for thermal modeling, light modeling etc. – these are useful for spatial innovation, not for material innovation. Because non-standard materials are hard to model with these software packages. It may be possible (with the PEB thermal modeling software package for example) but even for professionals, using that software is hard and expensive. Ideally there would be open source software packages that encapsulated the complexity and allows non-professionals to take over design and modeling tasks formerly reserved for professionals. However, that seems not to exist (yet).

    A more appropriate technique for such a setup is to create a setting (both physical and by social organization) that is welcoming the construction innovations. This can include, for example: a building that is simple to re-configure; piping and wiring that allow to install new innovative machines and devices wherever people want; a large on-site workshop that allows to adapt the building and its equipment quickly.

  • Innovation is hard. To make living greener, invest in human expertise instead. Innovation of products and materials often does not work at the start, and requires a lot of experimentation before it is ready for general use.

    For a small-scale setup like a communal living space, a more appropriate way to innovate green living could be “process innovation” for building maintenance. Basically, build up a system so that the community can maintain its own space: train different members as plumbers, electricians etc. and also get the relevant tools so that all problems can be fixed with little effort, extending the building’s utility, lifetime, and eco-friendliness. Investing in human expertise cannot go wrong, while investing in new materials and technologies may go wrong.

    A simple example: a concrete wall made from some new composite is not self-maintainable and may thus only last 50 years. There is no real need for such a wall though, as brick walls have been around for hundreds of years and we know how to maintain them for that amount of time. Innovation is also important, but one of the greatest values of a building is that we can keep it alive, and that is an important aspect of buildings being “green”.

  • The impact of human care on buildings. Buildings don’t last “100 years” like that, it can be 30 years or 300 years depending on the quality of their maintenance. So the cost of providing a function for a certain time is more determined by the care afterwards than by the initial investment. For example, Renzo Piano will rebuild the bridge that recently collapsed in Italy, with a version in steel that “will last 1000 years”, as he says. He did not mention with what maintenance. And bad maintenance was the main reason why the first bridge collapsed. So whatever you build, don’t care only for materials and high-tech, also care to put money into operation and maintenance. Because it is a new approach, this is innovative for the current time. Modern “sensor and IoT equipped” buildings can be a nightmare to maintain.

  • On new facade materials (like PV panels). There is a house in Australia using PV panels as roof covering, somewhat tilted so that light can still get through to the inside. In architecture, there are multiple uses of wall finishing / cladding: weather protection, and allowing the building to breathe (humidity transfer to the outside to prevent humidity buildup, mould, dampness indoors etc.). Depending on weather condition, the outer layer is of different permeability, impacting how the building is breathing. In some parts of Portugal, tiles are used for example.

    So to start hacking together a new cladding system (such as from PV panels), a good tip is to start with experimentation. Nothing too big, nothing too drastic at the start. “Play with it.” Just to see how the material behaves, how it can be attached etc… It will be difficult to pull off such a hack, as the material was not designed for such a use, so may perform worse for it than industrial cladding systems. Or at least it will probably not perform better. For PV panels, a purely ornamental use (plus power generation of course) of PV panels, or a use as a sight protection / separation wall on a fence or similar, could be the first experiments, as not so much can go wrong.

  • Economics of reuse, recycling and local production. Stuff is not made to be recycled today, and industrial-scale recycling is mostly about destroying everything, sorting the stuff and re-using the glass, metal and some of the plastic. Nothing is re-used for what it because that is a lot of manual work. And manual work is not time efficient, and we have not enough money in Europe to pay people for much of their time anymore. Just enough to pay them for operating machines – everything else is manufactured by machines or in China. The same limitations apply to unique construction of houses – instead, all new houses now look very similar, and the look results from the optimization to be built with machines, not with manual work. Again, the same limitations apply to building maintenance: in earlier centuries, a building was always maintained so it could live “forever”. Now, buildings have an expiry date and are then destroyed and replaced, because maintenance is “too expensive” manual work that cannot be automated away.

    In communal living, there is no general solution to that, but at least a partial one. Namely, comparing the cost of worktime and machine work is just a financial comparison that does not capture all the value. By working less outside of the community and more inside, people will have fun making their own things “inefficiently”, and in total may prefer that to working for money and buying industrially made items. That’s even more applicable when starting to make things not from scratch but from the waste of the surrounding society, such as all the stuff one can take out of buildings before they are being destroyed.

  • On the development of architecture. The traditional architecture in different areas is very different, also within Europe. It developed over hundreds of years of incremental development. In the last 50 years, that changed a lot, so now most new houses all around Europe are built very similarly. Is that bad, and should we rather just trust the traditional, accumulated knowledge?

    Indeed, architecture always changes, and traditional knowledge gets lost. We don’t understand a lot of building features of traditional architecture and material use. It’s ok that processes change, the problem with the new processes is that they are not developed from careful observation of the objects and environment. For example, houses are optimized for efficient construction and not to last (because “cheap materials, expensive labor for construction and maintenance”). Similarly, commercial buildings like banks are remodeled every 7 years.

    New ways of green building can be informed from this process of “careful observation” of the past. That will allow to build with cheaper and more environmentally friendly materials in a way that achieves the same or better effects as with today’s “modern” materials.

2. Building features and space utilization

  • Workplace / office integration. Offices are a very inefficient use of space: they are empty 16 or 24 hours a day, and still consume resources and represent embodied energy and emissions. Rather have your office in your home, for example a super-easy-to-clean room that is an office during the day and a party room in the evening. To be easy to clean, dangling furniture mounted to the ceiling could be a new approach.

  • Starting from an old office building. The advantage here is that partition walls etc. can be easily removed and reconfigured.

  • On unused buildings. An unused building is a waste of embodied energy and emissions, as it will decay even when not in use, and even faster, without providing any use value in return. However, nothing is won if the empty buildings are filled with capitalist money-making endeavors like rental apartments, for-profit businesses or even temporary rental contracts that can be cancelled within two weeks (as done by Camelot). They should be filled up with pro-social projects and activities: sustainability, not money-making. Because today’s money-making is very expensive considering its effects on the future.

  • Mobile conversion kit for temporary spaces. That’s a different approach to having an “own” space, and much simpler to realize: have a container with a kit to transform any abandoned building into a comfortable space within 7 days for 1-3 years of temporary use, with 2 days at the end to take all of that equipment out again. If this is about buildings that will be destroyed anyway, it will even be ok to remove walls and change the structure of the building when moving in. Utilizing abandoned buildings is also environmentally friendly because the continued maintenance extends the lifetime of these buildings.

  • Investment security and temporary spaces. The real reason why temporary occupation is not a perspective for middle-class communal living is: there is no perspective to keep the investments made into changing and renovating the space. And the investments middle-class people make into buildings are usually their only savings, so they really want to safeguard them.

  • Build something old, not something new. Trying a conversion to make an old space look new is difficult, esp. on a budget. But trying to make an old space look old but great is much simpler and cheaper. It just needs old materials and good “shabby chic” taste.

  • Communal music room. Another nice thing to integrate. Needs equipment, lockers for equipment, soundproofing etc… Makes for nice communal activities, getting to know each other, including by inviting bands from outside the community to practice.

  • Communal living with or without apartmentalizing. If everyone has an own apartment and on top the communal spaces (party kitchen, courtyard, swimming pool etc.), it becomes more expensive per person, less space efficient and less resource efficient. It can work well in social terms, though. There may be a middle ground of providing individual rooms with private bathrooms each. Student housing in the UK is like that, but not quite. Also, youth hostels are like that, but not comfortable for the longer term.

  • Floors as sub-structuring. In the Cent-vingt-trois project in Brussels, floors emerged as a natural way to structure the space. Each floor had a certain dedication / specialty, for example children, receiving guests, or punk / anarchist aesthetics. The higher up the floor, the fewer random visitors it would get as there were no stairs – effectively allowing people to choose their level of privacy. People could move between floors, and that was the mechanism how the personalities of floors naturally emerged in the first place. This mechanism allowed people to live with people they like, and avoid people they don’t like – which always happens, and is a larger problem in smaller communities where there is less space.

  • Person-tracking IR heaters. A version of the parabolic electric IR heaters mounted on a person-tracking pan-tilt head could be an interesting, low-powered way to keep people warm.

3. Dealing with rules and laws

  • Incentive problems with utility costs. In Brussels, a lot of rental contracts come with flat rate costs for water, electricity, gas and heating use. That is a huge problem that prevents green living, as there are no individual incentives against excessive consumption resp. for frugal consumption. So none of the ~80% of consumption reduction by behavior change is realized in such living situations. As a solution, utility companies should provide services (“a warm house”) instead of materials (“gas”), as that gets the incentives right.

  • Incentive problems with insulation and rooftop PV. In Brussels, houses are often rented out by absentee landlords who have not much of an interest in a building beyond it generating rental income. So they will not insulate the building better (and heating costs are paid by tenants anyway). They will also not install rooftop photovoltaics (and that is compounded by collective ownership of apartment buildings, where owners have a hard time agreeing even on essential investments). This could not even be really solved by a current comfortable offer by a Belgian company to “make your roof earn money” by letting them install photovoltaics there. As a solution, the city could take over the rooftops and mandate the installation of photovoltaics, similar to how they can mandate the installation of streetlights on the walls.

  • Routing around regulations. If you have no close neighbors, it is much simpler to ignore regulation because there is nobody who will complain to the authorities. Also, try to break only rules for the inside, not in relation to the outside environment. Then, the problem only arises when you want to sell the building – then an architect will have to check what has to be changed for that to be possible. So that will be the time to undo ones hacks and changes – and when keeping the house, it will never be a problem.

  • Combining houses in the city. Buying adjacent houses and making them into a single house by knocking down walls is prohibited in Brussels. But you could just do it, and put up the walls again when moving out :slight_smile:

  • Dealing with fire safety. In cities, public and communal spaces are tightly supervised by the fire brigade. They may mandate the type and material of walls, fire protection doors etc. to isolate buildings against each other so that there is a safety window for people in one part if another part catches on fire. For example, staircases in large buildings will have to be isolated from a kitchen space with a fire safety door.

  • Non-financial return on green investments. It can be that a change of technology towards greener, lower-consumption solutions will not pay for itself over its lifetime in financial terms, but still be worth doing it because of the environmental benefits. For example, a rainwater system may not pay for itself from the freshwater costs it saves, but it helps to prevent groundwater overuse (esp. in the drought years, which will be more frequent in the future climate). Similarly, replacing a car with an electric version may not pay financially for the car’s owner, but may still be worth doing. (Open question: Are there frameworks to evaluate what is worth doing even though it’s a financial “loss”? Or lists of such interventions?)

  • The off-grid neighborhoods of Nice (?). After the last economic crisis, some poor neighborhoods near Nice broke off all grid connections to the city, and manage their own water, wastewater and electricity now. This is interesting because it shows how off-grid solutions can also work for the poor, instead of being a thing to play for the rich. [see: 3:29:57]

  • Certification issues with material re-use. Any certified component of a building is not legal to be put to use again in a new building. The certification only applied when that equipment was installed the first time, but now the standards might be different and not cover these items anymore for getting a new building certified. For example, emergency lamps. All these items are now considered waste. It especially also applied to electronics components.

  • Right to Repair and its limits. In Europe, we got the “right to repair” legislation a few months ago. It is a good basis for more resource efficient living, as in principle it allows DIY repairs to household appliances etc… However in practice, many manufacturers cite “safety concerns” to prevent consumers from getting their hands on their repair manuals, and provide them only to certified professionals.

4. The role of lifestyle and behaviors

  • Consumption is 80% of the problem, construction 20%. The energy costs of constructing a house is 20% of its total lifetime energy costs, while the energy use during its lifetime is 80%. That says something about priorities for “greening” city living!

  • No-plastic living. Have a (communally researched) list of local purchase options etc. for no-plastic-packaging food etc… Share your grocery shopping – that is needed to be able to get items plastic free, as these shops might be further away, or sell in larger quantities.

  • Low-hanging fruits of green urban living. These are: not having a car, shorter commutes, lower heating costs as houses are in blocks.

  • Greening the lifestyle of the whole neighborhood. By integrating social projects such as clothing exchange events and rescued food distribution, a community can make the living in the whole local area more green, not just its own. It would be interesting to do the numbers for that, and it may turn out to be the most efficient way of emission reduction. From Bernardo’s experience, a best practice to do these social service projects is to do those that also profit yourself, because then it’s not a net drain on the organizer: if you have kids, organize kids clothes exchange events; if you cycle, organize a cycle repair workshop; if you like dancing or working out, offer dance classes or open a gym in the communal space.

    These can also be semi-commercial activities and still be a net benefit for the neighborhood. It provides a public good because of “zero marginal cost”: scaling the service up to more people beyond ones own and direct community’s needs does not really cost more, so can be provided as a service at a low price or even for free.

  • Use rescued food as much as possible. That’s a major aspect of greener living that is possible in community, and less possible in small households. Because with more people, larger amounts of rescued food can be utilized, with a large commercial kitchen food can also be preserved easily etc… On top, rescued food can be shared in the neighborhood, which makes urban living greener even for others.

  • How to make communal living attractive to the middle class? They don’t have a need to share space, because they can afford not to. They don’t have a need to change their lifestyle to be greener. How to motivate them to engage in green communal living then?

    Another position on that is that some middle class people would like to live communally (“Being a migrant and living as a couple in an own flat in a new city sucks. People don’t want to do that.”). And that this need is not served by the market (constructing single-family homes), including banks (funding single-family homes). It’s hard to find a large house with multiple bathrooms, for example.

5. About communal living in more general

  • Children-friendly architecture. Architecture that looks at the built environment also from a child’s perspective is rare – often, windows are too high for them to look out, for example. If you are going to convert a space anyway, why not include that perspective. It may help community members to stay after having children, or even influence their decision to have children or not.

  • Unsupervised child play. In a communal space that is somehow enclosed (not like a gated community, but a bit …), unsupervised play is simple, even in today’s age and in cities. Children can become quite self-sufficient – @alberto mentioned how in such a neighborhood in Milano, the children made all the adults keep their doors unlocked so the kids could go in and out of the houses of their friends to get water, go to the toilet, meet their friends etc… It made the environment more social for everyone, and is more efficient regarding adult attention. It’s not directly “green”, but frees up precious time for other activities, including for those that take more time but less other resources and are thus part of “green living”. It also lowers the need to move children around in a car between activities.

  • Provision for children activities at home. “Do you really need your children be driven to karate and back? Make them a football place in the courtyard instead.” And similar approaches. It uses less energy for transport, and it frees up adult time for other aspects of a greener lifestyle, which is often more time-consuming.

  • Add a garage! A large, 4.50 m high garage is a very handy, multi-purpose space to include in a communal living setup. Can be used to house nomads coming with their van or truck, to host parties, to store stuff etc…

  • Social housing is not communal – but should be. All social housing is subdivided into family-sized homes, without any communal spaces that are shared with others. (“Because communal space is public space, and public space tends to be aggressive to individuals with low income, mental or health issues etc., on the basis that people from different backgrounds cannot relate to them, and cannot profit from them.”) Still, there is a large need in such social housing situations for shared spaces, out of economic necessity: social housing is precarious, it means small houses shared with many people. Shared spaces would make comforts of a middle-class lifestyle available to lower-income people. This need was served by projects in Brussels like Cent-vingt-trois (see below).

  • Dealing with problems, not avoiding problems. Problems – mostly the social ones – will happen in communal living. It’s not so much about avoiding them, rather about building a community that can deal with them. An important point for that is that community members must have time to invest in building the community and its communal spaces and collaborations in the neighborhood – instead of working for money to pay the rent. A cheap rent per person is crucial for that. Because “how do you build a community when you arrive at 18:00 in the evening?” That lack of time would result in unresolved tensions in the community.


I love this one! I had a look at the MAMA page and thought: yep, yep!, yep!!! - someone is starting to think about this right. I think Kurzweil would like this.

There is a related story that begs to be published more widely on the Roman roots of the Canal du Midi in France (which was a kinda big thing, so much so that the early US studied so they could make copies). The point there is that a bunch of housewives in the Pyrenees kept kept advanced civil engineering alive cause they just really liked to have warm water in their place. Those ladies ended up being the smart girls on the block when it came to hydraulics in civil engineering.
As materials scientist I can only applaud that maintenance could be approached as a socio-technological question.

On new facade materials (like PV panels)

I agree generally. What I’d recommend is to use them in secondary functions that allow easy documentation (images at (semi) regular intervalls is easiest). BUT I would also hook up a few of them to be fully functional - even if it just powers 5-10 ornamental lights.
This will inform your next batch of experiments and how easy or hard it will be to get it right. How many of the first 10 will fail? How did they fail? If you picked 5 that you tried to fix in 5 to 30 minutes - how many of those survived?
You want to do many of such experiments in parallel and probably abandon half of them at some point, and in Pareto style focus your resources on the more important ones over time.
If you want to step up the testing regime I recommend gravimetric analysis of water content (i.e. get a really good balance, and a tool you can take repeatable material samples with).


I’d like to plug this here, also check the key publications if you have time. In my opinion a very good resource - no least because it is already written in “policy speak” and has been largely born out by reality over the last couple of decades:

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That story is absolutely amazing! I mean, keeping a whole discipline of engineering alive for ~1300 years and through the Dark Middle Ages, to be able to maintain your home’s water system, is a whole new level of dedication … . And I’m really happy with the part women play in this story :blush: I’ll send this to Bernardo, maybe he likes to include it into his case study collection on MAMA Brussels.

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Wooow, I totally love this approach!

About this, I thought of something that was not in the list of questions, but should have (my fault! and am now throwing myself on @trythis’s mercy for an answer). I worry that no one seems to know what happens to Portland concrete in the really long run. In some countries, like Serbia or Bulgaria, I have seen gigantic concrete apartment blocks that were built in the 1950s to 1970s as modern housing, but have degraded significantly over the decades. Even in central Belgrade I saw buildings that exhibited a kind of rot; they were obviously deemed too expensive to demolish or rejuvenate. So poorer and poorer people moved in: first professionals, then working class folks, then students, then squatters, then rats. Trees grow in the courtyards. Is this the destiny of all the concrete in the world?

it comes together very nicely from the workshop, because armored concrete was also a modern and hip technology, stemming from materials innovation. And now we are looking at the gigatonnes of it we have poured and wonder what’s going to happen to them…

Or, more simple/cheaper/less brittle: have some “warm spots”. For example, when I sit at my computer in the office I turn on an IR beam trained on me. The rest of the office stays cool.

Maybe The Reef’s motto should be the quote (I have heard it attributed to Henry Ford in the context of the Model T’s design and production, but cannot find a confirming source):

What is not there cannot break down.


A quick search pretty much confirms our suspicion:

Research on concrete is still pretty hot. But to put it simply: water diffusing into concrete, or more commonly seeping into cracks is a major failure mode. In a somewhat disused building I would suspect you commonly have half a dozen failure mechanisms already with a solid foot in the door, and thus beyond economical reversal.

If I recall correctly freeze-thaw cycles and certain substances (e.g. salts) generally speed up the degradation process drastically.

For many structures 30 years useful life is regarded the higher end, and as far as I know concrete is not something that lends itself well to conventional or targeted repairs.

More on the topic here: Google Scholar (these are the fairly recent articles citing a influential 2001 publication: Assessment of the durability of concrete from its permeation properties: a review)

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Water, rust, freeze/thaw cycles definitely degrade concrete. Also how much steel reinforcement is in there, proportion of sand, things like that. My family has a vacation cabin in the mountains by a river. To get there you have to cross a bridge that is collectively maintained by a group of residents. One of the residents lives there year round. She kept sweeping the snow off of the concrete bridge surface, thus removing an insulating layer, which caused the concrete to expand and contract to the point of failure which let water seep down into the rebar, which rusted. Cost $100K to fix. IF she had used snow tires none of it would have happened.


There is a ton of valuable information and many great points in these notes. I’m sorry I couldn’t attend.

I agree with the opening point about investing in human expertise. When first heard about this Reef project I thought it would be valuable to have each major maintenance discipline handled by a resident. I was reminded of the 1960s movie “The Great Escape” where one guy was the forger, one was the scrounge, one was the tunnel rat, etc.

I lived communally for five years in Washington DC (1978-1982). We weren’t all that green back then, but we did have various specialties for keeping the place going (this house had 10 bedrooms and sometimes more than 30 residents, including a bunch of kids of various ages). I took care of the vehicles and the appliances. Someone else looked after the plumbing, another carpentry projects, one was the food buyer, etc etc. This works way better than some sort of signup sheet. Also, everyone has to wash dishes and keep the floors tolerable…

I also think that along with technical know-how, one much have a certain amount of social skill along with a ready willingness to admit when one is wrong. Living together means clarifying things, usually more often than a lot of people feel like doing. But not tending to the emotional and mental wellbeing of the group is as bad and probably worse than not cleaning the kitchen or the floors and other basic material maintenance. Otherwise, it’s really a rooming house, isn’t it?


A couple of years ago I read something by Bruce Sterling talking about his place in Torino, Casa Jasmina. The idea was to experiment with all sorts of smart home tech kind of stuff, arduino-based projects and such. They set it up to designate a section of this (big old reclaimed industrial space) only for experimenting. I think that is an interesting idea for a green space - if you have the space. Kind of an in-house, somewhat funky lab.

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How true…

Is Casa Jasmina Bruce’s home? I think it’s a kind of Arduino demo site…

They were living there a couple of years ago anyway. But Bruce lives on Ibiza part of the year too. But when @pbihr visited there a few years ago they were living there and running a lot of experiments.

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I ask because at one point it was available on Airbnb. And it seems it still is…

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How interesting…might be fun to check it out.

Damn it, we were just in Turin for the NGI thing :slight_smile:

You should check out Admir Masic’s work at MIT regarding this

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I will!
While I was there I was working in a dusty underground blast chamber, so I definitely didn’t want to spend more time around concrete than I have to. But his stuff looks really cool and interesting (from a far away sunny place :wink: )
Thanks for the pointer!