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SCIS Podcast Episode 5: Smart Wood

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Monday, March 4, 2019

Anthony Colclough: Hello and welcome to Urban Reverb, the SCIS Smart Cities Information System podcast. I'm Anthony Colclough. You can find links and the entire transcript of this episode at

Today I am speaking to Anders Carlsson of the Varburg demo site, and Dominique Deramaix of the Stambruges demo site of the Need4B project.

Anders Carlsson: Hello Anthony

Anthony: Anders is going to tell me about new energy efficient buildings made from an exciting smart material.

Anders: I will try, and if you don’t understand my English then you will have to ask me again.

Anthony: This is a material that is climate sensitive, automatically adjusting to changes in temperature and humidity, a material that provides great insulation and can be sourced sustainably and locally in any city – that material is wood.

Anders: Derome is a huge family owned wood company in Sweden. We are building prefabricated wood houses.

Anthony: And this ‘wood’ stuff – you claim it’s eco-friendly?

Anders: Now I don't really understand you, but do you want me to explain why wood is so eco-friendly? Yes, yes wood is eco-friendly because it's renewable, so it will store carbon dioxide. When the young tree is growing then it adds carbon dioxide and you know this with photosynthesis. So then it stores the carbon dioxide and it produces oxygen. When you use steel or concrete it's got a huge carbon dioxide footprint. So that's why wood is so eco-friendly. If you don’t want the building it’s easy to reuse wood in different stages and so you can use it, reuse it as studs or boards and at last you can burn it and use it for heating. And then you, of course when you burn this product product then the carbon dioxide will get free into the atmosphere but then the new growing wood trees will absorb again, so then it will be like this cycle.

Anthony: You’ve got to love that carbon cycle.

Hard n’ Phirm: [Singing] Carbon cycle, we are part of nature, we are part of nature’s plan.

Anthony: The best part is, in accordance with Swedish Law, Anders’ company plant four trees for each tree they harvest. Keep building these houses and soon there’ll be no more room for people. Carlsson explained that wood also has other, mysterious, occult properties.

Anders: We are not really sure why people who live in these houses can feel better. They are not so sick. And if you stay in a hospital with wood internal cladding, you understand what I mean, wood as internal cladding, you get less days at the hospital. You don’t have to stay at the hospital so long, so you can go home earlier when you stay in a in a room at the hospital where you can see and feel the wood cladding. And that's the same in the in a house where you live: there is better air and you get more calmer when you can see and feel the wood.

Anthony: Wood also has inbuilt humidity control.

Anders: Wood lives together with the moisture so if there's a high moisture in the room the wood

absorbs moisture and then when it's dry air in the room the moisture goes back to the air again. So there’s not so high humidity and there's not so dry, there's more an even grade of humility if you compare to a concrete house.

Anthony: And it also works wonders for insulation.

Anders: Wood compared to steel and concrete, you don't lose so much energy through wood because it's a really good insulation capacity in itself at the same time as it’s a structural material. But of course we use insulation between the studs.

Anthony: Concrete and steel do have an air of permanence about them that wood lacks. We know wood rots, snaps, and gets eaten by little bugs. Au contraire, Anders assured me, the evidence does not confirm this prejudice.

Anders: Do you know the Vikings? During the Viking times they built churches in wood and you can still visit churches that it’s over one thousand years old and it’s built in wood.

Anthony: You won’t catch me trying to pick an argument with the Vikings. Sweedish architects are also becoming more fond of wood as its properties offer design possibilities different from more modern building materials. Depending on the local environment, wood can also be safer than other materials. In San Francisco, wood is popular because wooden structures have a better chance of withstanding earthquakes.

Anders: I’ve see pictures of China where a lot of building was built in concrete, and there was a few built in wood, and every house in concrete was destroyed, and the one in wood stands alone. And nowadays we are building multi-story buildings in wood, so we are building eight or ten stories in wood.

Anthony: Wood does, however, have one rather more famous material property…

Anders: Of course, it’s easy to think that wood burns very easy. Of course if you make a fire then it’s easy to make fire with wood, and then you chop it up in small sticks, in small pieces, then it’s easy to get wood burning. But when you try to burn a huge beam, a wood beam, it’s not easy to get a fire to burn through the whole beam because when it has started to burn, it gets this insulation in itself. You understand? When it has burned the first centimetre then it will be insulation in itself and then it’s almost finished to burn. So, wood houses, in some way it will burn but after a while it will not burn any more. But of course we have to protect it with some gypsum board and so for fire protection.

Anthony: For the Need4B project, the traditional wooden design did get a couple of cool updates, including a thermal heat pump, solar panels on the roof, and ventilation with heat recovery, so that the warm air going out of the building heats the fresh air coming in. They also have lots of insulation in the roof and low-energy windows that keep the heat in. Anders is confident that this style of building can be replicated in other countries with Nordic climates, but he also sees no reason why it couldn’t be used in hot countries where its insulator properties would help residents stay cool.

Anders: Now we know how to produce it, and we got the drawings and the solution, of course we haven’t thrown it away. So now we have the knowledge how we can do these houses.

Anthony: Unfortunately, a bespoke wooden house does come with a pretty serious price tag. But that might change in the future.

Anders: Of course it will cost the customer more if they should build a house with these solutions then it will cost much more. If you ask me that you should just buy one house, then it will cost more. But if you say that the whole market want to buy this solution, then the cost will be reduced.

Anthony: With the exception of another wooden house in Belgium, the styles and materials used in the other demo-sites of Need4B were quite different from those in the Varberg pilot. Because of this, there wasn’t a huge amount for Anders and his team to gain from the international cooperation element of this project.

Anders: We asked each other a lot of question about the regulation, consumption, how they heat their houses and, so of course we compare it in that way. But in Istanbul they build their university in concrete, of course this is a huge building compared to our single-family houses in Sweden. I wish there should be more single-family house builders but from different countries then we should learn more and get more topics to discuss.

Anthony: Having said this, the exchange did give Anders a chance to learn about Turkish customs.

Anders: I remember once in Istanbul when we visited a Ukraine restaurant, the Turkish partners they start with dancing hand in hand, like a ring, through the whole restaurant. Did you understand what I mean? Like you when you're dancing around the Christmas tree. You do that in Ireland? In Sweden we take each other’s hands, a lot of people, and we dance around the Christmas tree. We did it in Turkey too and it was a Turkish tradition to dance very fast round, round a lot of people through the restaurant. And that's one funny thing.

Anthony: There is a push in Europe plan for denser residential living, and in many areas the single family home is fast becoming a thing of the past. However, Anders told me that the desire for such homes remains very much embedded in the Swedish psyche.

Anders: Sweden we want more people to live in the same area in multi-story buildings. So the municipality when they create new areas for buildings they want us to build multi-story buildings and they don't want us, allow us, so much to build this single family houses. But in Sweden, 70% of the people in Sweden want to live in a single family house. So the government want us to build higher buildings in small areas, but the people who live in Sweden they want to live in a spacey areas in single-family houses. So I think a mix it's the best. Those who want to live in apartments in multi-story building, let them live in those buildings, and those who wants to live in single-family houses, let them live in single-family houses.

Anthony: The other single family home in the Need4B project is in Stambruges, Belgium. It was built by Dominique Deramaix founder of Format D2 architects, who now lives in the demo site building. This wooden home is breaking ground on what it means to be a passive house.

Dominique Deramaix: The passive house is 120 kilowatt hours per square metre per year maximum. And here for the project it's a half, so it's a 60 kilowatt hours per square metre per year but my house is 35 kilowatt hours per square metre per year.

Anthony: The construction is a little different to the traditional Sweedish houses that Anders was working on.

Dominique:  Here it's a house with CLT panels, it’s ‘cross-laminated timber’ with five layers of wood, cross wood with glue and the walls are ten centimetres of thickness and it's big walls of 2.5  meters and 10 meters long. And all is assembled with the screws, and the construction is very, very quick for the house which has 280 square meters. The house was built in six days, for all the wooden structure. After, you have all the finishings, but for the structure it's a very short time. So you can have very open spaces for modern architecture with this type of wooden construction. And with the layers, with four layers of wood, between the layers you have the glue, and also the glue has also a function to cut the humidity, to have a hair tightness and a vapor barrier.

Anthony: The Need4B managed this through constant monitoring. They monitor, make a change, and monitor again. They cut power by switching incandescent bulbs for LED lights, choosing a more efficient freezer, and using a heat pump for the hot water. They managed to save power by putting the heat pump in the same room as the washing machine, drying machine, fridge and freezer to take advantage of the excess heat from these machines.

Dominique: All items use a lot of energy, so it's the warmest place in the house. And with the heat pump, we can take this hot hair to refresh and to have a better COP for the heat pump.

Anthony: COP is ‘coefficient of performance’, which is just a measure of how efficiently a machine does its job. The main source of heat for Dominique’s house it that great ball of fire in the sky. That’s not something we see a lot of here in Brussels, but apparently in other parts of Belgium it’s doing a better job.

Dominique: Here the houses is implemented towards the South to have a lot of sun. Because there is no heating for the passive house, just a little fireplace with a chimney. But for all the winter the consumption of wood is two cubic meters, not more, so for a big house for family. And so for architecture, all the windows are oriented towards South. Also we have decided to have a single roof with a single slope oriented also by the South, to maximize the surface of the roof to place photovoltaic panels. So we have, in two months all the roof will be changed by integrated photovoltaic panels, like a photovoltaic roof of one hundred square meters.

Anthony: And that’s not the least intuitive thing about this home. The warmest time of year is also… unexpected.

Dominique: The best moment in the in the year is when there is minus 10 outside. Without heating we have 20 degrees inside. Because by minus 10 you have no rain, no clouds, you have only sun and here the sun is not too high. So the sun is coming through the frames and does the heating of the house.

Anthony: Dominique told me that such houses remain difficult to build in terms both of zoning and finance. Though it was eventually approved, he had a hard time convincing planners of his non-traditional single sloped roof for capturing all the best solar energy. And though this home was financed by the project, there are few financial incentives for people to build for such high levels of energy efficiency. Banks do not account for the benefits of this kind of housing when they consider loan agreements, and the Belgian government does not use sufficient push and pull techniques to make investing in homes like this worth people’s while.

So there you have it folks, wood is good, and smart cities of the future still have a lot to learn from the past. To find links to these projects, plus a full transcript of this episode, check out, and you can get in contact by emailing me at


Need4B project




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