straw Archives - IsoBio Project

Bio-based houses are seducing Latin America

The use of natural materials is growing rapidly in Argentina and other South American countries. Technical progress and policy implementation seem to go hand in hand

The green building phenomenon in Latin America has taken off. Bio-based aggregates have started penetrating the construction sector’s market, and the development of eco-friendly renewable products has increased the use of bio-based polymers in the construction industry, as a recent study shows.

South America is one of the emerging markets where a major demand in natural materials for buildings is expected in the next years. People today are indeed increasingly persuaded that they can safely get the same quality level as traditional products.

The policy implementation in the region following suit. Brazil, Mexico, Colombia, Chile and Peru have carried out different measures ranging from relevant tax cuts to soft loans for sustainable construction.

Although in Argentina this is still a new phenomenon, the situation and legislation are quickly changing. “In my country public interest and the market are also growing because young people are getting involved and interested in this topic,” says Juan Manuel Vazquez, an Argentinian agricultural engineer, who started using bio-based material for construction 15 years ago.

“I was working in an agronomic olive oil industry and I found that olive oil can lose quality in storage, in particular in countries with extreme climates. That was also when I first heard about straw bale warehouses, used for storing bulk food because of their insulation properties,” he told youris.com.

He later became co-founder of Henia Carbono Negativo, a company that develops pre-assembled panels of straw bales, using 100% biological material for dry construction, with high thermo acoustic, mechanical and fireproof performances. It was in La Cumbre, Córdoba, that they built their first family house of 250 m².

“We are now working to conquer the mass market, it will take time but not that much,” affirms the expert with conviction. “I recognise that my method may be a niche one, but I think that economic paradigms are changing. People are willing to pay a little more for green materials because it’s a matter of health and well-being.’

An eco-friendly house in Argentina would cost only 10% more than a traditional one, on the basis of Manuel Vazquez’s estimations. He also says that thermal insulation is seven times greater than that produced by a double hollow brick wall.

It is also resistant to fire and earthquakes. The straw used is kept compact, and without moisture, and it does not attract insects of any kind. High insulation potential, no pollution, and the fight against climate change are just some of the reasons which motivate him.

Henia’s experience is in line with ISOBIO, a EU project that proposes a strategy to mainstream bio-based construction materials. This is another source of inspiration for Manuel Vazquez. According to the European researchers, bio-based construction materials are in fact capable of achieving a 50% reduction in embodied energy and CO₂ emissions, with 20% better insulation properties compared to conventional materials such as bricks, cement and beams in walls and roofs.

There are several signs of policy changes to promote energy efficiency in Argentina’s buildings. For example, the city of Rosario has implemented a certification, carried out in 500 homes, which enabled household performance and energy-saving potential to be identified.

Specialist in bio construction Maria Loreto Retamales lives in a bio-based house in Valparaiso, in Chile, but her first eco-friendly house was in Argentina. “Ten years ago, I decided with my family to live in harmony with nature,” she explains. “I read about the architect Nader Khalili, his Cal Earth Foundation (California Institute of Earth Architecture), and his research and work with soil and sack.”

She studied his technique called “SuperAdobe”, a form of earth bag architecture, and now she trains other people on it as well. “In less than a year, I even gave workshops to architects and engineers in Argentina, Chile and Bolivia,” she tells us.

House built with the SuperAdobe technique. Photo credits: Maria Loreto Retamales

Maria Loreto has no doubt: “Living in a natural building has big advantages such as a more stable temperature and humidity. People don’t get ill so much. Moreover, earth isolates from the sun’s radiation and electromagnetic waves.”

Argentina has one of the most recognised bio constructors in the world, Jorge Belanko, specialised in earth buildings. Of course, this technique still remains quite unusual, but in the last 10 years Maria Loreto has seen hundreds of innovative projects developing.

Finally, one of the architectural symbols of the growing movement of natural builders in the country, is Tol-Haru, la Nave Tierra del Fin del Mundo, the first self-sufficient house in Latin America. It was built in Ushuaia, the closest city to Antarctica in 2014, using recycled materials. Wind and solar energy provide heating and cooling. The shelter also reuses rainwater and it even recycles waste.

Its construction has been promoted by the actors Mariano Torre and his wife, Elena Roger, members of the NAT Foundation (Nature Applied to Technology). The visionary architect Michael Reynolds helped them through the construction process.

By Anna Maria Volpe

Cover credits: Juan Manuel Vazquez

10 May 2018

Compressed Straw Board

Compressed Straw Board (CSB) is a wall construction and lining material made in a continuous process by heating straw under pressure in a Stramit International machine.

A solid board is produced which is 100% pure straw, without extra binder, the lignin in the straw being sufficient to act as a binder during the process. Normally it is covered with a paper cover during the process.

CSB is produced in solid self supporting boards in thicknesses of 40 or 60mm and 800 or 1200mm widths, at selectable length between 1.5 and 3.9m.

Functions

CSB is used to face the internal wall and ceiling surfaces of buildings by fixing to the structure, and can form self supporting internal walls (partitions). It can be plastered in clay or gypsum, to a fine finish.

CSB has a thermal conductivity value of 0.1 and as such is part of the thermal function of a building, usually supplemented by less dense insulation. It is vapour permeable and contributes to the moisture balance within a building, buffering changes in air humidity. Being of medium density CSB acts as a sound absorber and contributes to acoustic insulation between rooms in a building. A single 60mm board with a plaster finish provides 60 minutes fire resistance.

Impact

CSB demonstrates low embodied energy. It is 95% straw – a waste product of agriculture gathered into bales and transported to the processing plant. Processing CSB therefore uses little electricity.

Carbon Dioxide is sequestered at the rate of 1.5kgCO2e/kg or 30kgCO2e/m², considering only the straw component. Being a natural biological material the VOC content is negligible, contributing to a healthy indoor environment.

Straw scientifically proven as viable building material

Research has made affordable, environmentally-friendly houses a reality. The first super-insulated, low-carbon straw houses are hitting the open market.

Many technologies have promised these qualities, but few have been commercially viable. What’s been lacking is the performance data needed to demonstrate that these technologies are durable, genuinely environmentally beneficial, and suitable to be insured.

Over the past 13 years, our Department of Architecture & Civil Engineering has led on research into straw as a low-impact building material. This work, which has included developing a unique straw bale panel as well as scientific monitoring and testing, has now culminated in crucial industry certifications.

… Continue reading the original article on University of Bath website, here.

Homes storing CO2, just like trees

Houses built with bio-based materials, such as timber, straw and hemp, act as CO₂banks. Experts explain how citizens can become custodians of atmospheric carbon dioxide and thus help reduce air pollution

Domestic efforts play an important role in curbing global warming. Besides producing and using renewables, homes can also act as banks that store CO₂. This innovative building model exploits bio-based materials, such as timber, straw and hemp, which act as “carbon sequestrators.”

Carbon is banked through photosynthesis made by plants during their lifetime. “Photosynthesis is the means with which plants absorb atmospheric CO₂ molecules, and split them into their component atoms. The carbon atom is retained making complex organic sugars that are the building blocks of the cellulose, hemi-cellulose and lignin found in plant cell walls. The oxygen atoms are released back into atmosphere as a by-product. Therefore, photosynthesis converts atmospheric CO₂ into carbon-based materials that we can use to build and insulate our houses”, says Finlay White, expert in low energy “passive” buildings.

When plants die, the ground absorbs the stored carbon dioxide, which then finds its way back into the environment. However, if we use bio-based materials in construction, the CO₂ remains “imprisoned” in the buildings made.

But how much carbon dioxide can be stored in a carbon sequestration house? White explains that “depending on the extent of the renewable materials used, the gross amount of CO₂ equivalent stored could be as much as 55 tonnes for a typical 80m² house. Such dwellings would typically use timber framing for the superstructure and for the internal walls and floor, straw bale insulation in the roof, timber for the cladding and finishes, and other bio-based materials for use elsewhere.”

“The gross amount is the actual CO₂ absorbed by the bio-based materials used in the building. The net amount will need to take account of the energy used and subsequent CO₂ emissions associated with dealing with the forests and crops, and turning the materials into useful building products and delivering them to site. This is known as embodied carbon”, he adds.

“Therefore the calculation for a bio-based house will be the gross CO₂captured minus the CO₂ emissions embodied in making the house. A typical 80m²bio-based house with a gross CO₂ capture of 55 tonnes might well mean a net amount of 33.6 tonnes.”

White works for the Bristol-based green technology firm Modcell, which contributed to the construction of what they claim to be the world’s first commercially available houses built using straw (more info in this BBC report).

They are also collaborating with the European project Isobio, which is developing “new products that include compressed straw board that can replace plasterboard, cereal fibres combined with bio polymers to make components for door cores etc.”, says White, “Once a designer becomes aware of the use of bio-based materials, the potential for their use expands rapidly.”

Carbon sequestration houses still remain a niche market in Europe.

Callum Hill, senior visiting research fellow at the University of Bath, another Isobio expert in the field, points out that “the building industry tends to be very conservative in its approach and prefers to use what it is familiar with. Bio-derived materials are often perceived as being perishable, flammable and short-lived. These perceptions are not supported by facts”. Compressed straw bales used for building envelopes, for example, are not flammable because they contain less oxygen.

Hill thinks that governments should recognise this alternative storage of atmospheric carbon dioxide and “provide a financial benefit for custodians of it. “It is a way of storing atmospheric carbon dioxide that can be readily achieved and without financial penalty (unlike carbon capture and storage)”, he says, “This is something that can be done to the benefit of society and the environment. Anthropogenic carbon emissions are undoubtedly changing the climate and these will have huge financial implications”.

By Luigi Serenelli

17 November 2016

The Social Life of Bricks

A celebrity in the materials world, Mark Miodownik dreams of colour-changing walls and looks at the future of renewable buildings

Mark Miodownik will never forget the day he became obsessed with materials. He was a schoolboy in 1985 when he was stabbed in the London Underground. “When I saw that weapon in the police station later, I was mesmerized. I had seen razors before of course, but now I realized that I didn’t know them at all. (…) its steel edge was still perfect, unaffected by its afternoon’s work,” he writes in his bestselling book Stuff Matters.

Growing up, Miodownik turned his fixation into a successful career. He became a materials scientist at the University College London, the director of the UCL’s Institute of Making and a widely known speaker and BBC presenter. His research interests include biomaterials, innovative manufacturing, and sensoaesthetics, a science that investigates the intricate relationship between people and the materials they use.

We asked Miodownik to share his views about the rediscovery of traditional materials in modern architecture, and how tomorrow’s buildings will cross the border between new and old technologies.

Do you think there is still value in using wood, straw, wool, or other traditional materials for buildings?
I don’t see being “traditional” as a value per se. The choice of materials has to be assessed with modern criteria, which include sustainability and energy consumption. If you ask me whether traditional materials are appropriate for modern buildings, I think the answer is yes. Partly because traditional materials have a portfolio of properties that are sometimes better than anything we have created recently: wool, for example, is a fantastic insulator.

Partly because it’s the whole ecosystem that matters. In the old days, the building materials we used were part of the landscape, and they were easier to recycle. New materials are not usually like that. When it comes to sustainability, traditional materials are often more efficient.

Construction experts point to limits in the public perception. Some described the three little pigs syndrome, a misconception by which buildings made with traditional materials, such as wood, would not be not as stable or durable as concrete. Is this vision widespread? And does our cultural background influence how we perceive materials?
There is no simple answer. Anthropological studies show that different cultures favour different materials, but the ways people relate to materials is extremely complex. The texture, the feel, the colour or even the imperceptible smell of an object can affect our emotional state. The materials we choose for our house, or the clothes we wear, not only represent us are but they also change how we are. Therefore, the materials we choose for a building can have subtle social consequences.

However, I don’t think that the “three little pigs syndrome” you describe is so widespread. People generally trust the engineers and rarely think about buildings collapsing, unless they live in an earthquake zone.

Rather, I believe that the influence of the global culture is predominant. People worldwide associate concrete, glass, and steel with modernity – think of the iconic image of a skyscraper – and this cuts across many cultures, especially in countries that are switching from rural to urban.

In the industrialised countries, I see much more of the opposite syndrome: many people don’t like concrete and are looking for alternative materials to build their homes.

My sports shoes have a new waterproof layer and a classic leather upper. Will buildings go the same way, layering technologies and crossing the border between old and new materials?
Doing this will require more interaction between experts from different industries, and I would like to see more of it. The construction sector is not very diverse in its approach, and I think we have a problem with asylum mentality in general, but real innovators will cross the boundaries between disciplines.

Textiles, for example, are fascinating for architects because they can do things that normal construction materials cannot do. You can see this with the lightweight pneumatic panels that cover many stadiums. Temporary structures are another sector that could benefit from innovative textiles. Millions of refugees need decent housing. Smart constructions made with resistant and lightweight fabric could be quickly sent, packed and reused.

In the future, building materials will be more diverse because people themselves are so diverse with their needs and desires, and constructions will reflect that.

You suggested replacing school libraries with workshops where students could get in contact with materials. Does a digital generation really need the physical experience of touching and feeling stuff?
I think the digital world is just one aspect of life. It clearly isn’t the answer to everything. Humans are physical beings; they need food, sleep and shelter from the weather. My radical proposal came after seeing the massive decrease in the facilities for learning with materials. For some schools, digital technology has been an excuse to reduce the resources for physical workshops because they are more expensive.

Whenever we introduce students to physical stuff they love it. And if we combine their digital skills with material knowledge, we can actually empower them. Professionals, too, need to cope with the wealth of new stuff. The number of materials from which designers can choose has almost quadrupled in the last 15 years.

This is why we are now seeing more materials libraries: facilities that collect samples so that designers and engineers can find out how materials could be used.

What would be your dream material for a building?
I’ve always fancied buildings that harvest their own energy. On a more immediate scale, I would like constructions to be thermochromic, meaning that they would change their colour with temperature.

Buildings could turn white in summer reflecting more sunlight, and thus reducing the need for cooling. And they could become darker in winter to absorb more heat and thus save energy.

Thermochromic glasses are already on the market. My laboratory developed a thermochromic brick about 10 years ago. We couldn’t get any company interested, but we showed that such a brick was possible.

This material makes total sense from an environmental perspective. As an extra, I would love to be in a city where the buildings change with the seasons.

By Sergio Pistoi

21 April 2016

Low carbon materials to capture the imagination of homebuilders and owners

Innovation in the construction industry will play an important role in reducing emissions and improving energy efficiency — though developing new materials and methods is only half the battle. Convincing architects and homeowners of the performance and long-term financial benefits of a new product presents a significant challenge.

In Europe, households are responsible for 32% of greenhouse gas emissions and 42% of energy. Cement production alone contributes to 5% of manmade CO₂emissions.

By contrast, bio-based insulation typically have much lower “embodied energy” levels compared with more conventional building materials. Furthermore, the source materials themselves sequester atmospheric carbon dioxide via photosynthesis.

“The beauty of bio-based materials is that they are often a byproduct of growing our food. We can build with carbon. Instead of seeing carbon as a problem, we can recast our relationship with it to one of positive innovation”, says Craig White, director of ModCell, which produces straw-bale eco-homes.

The company is one of the 12 partners in academia, research and industry that are collaborating with the European project ISOBIO. It aims to deliver bio-based insulators with 20% better performance than conventional materials, leading to a 5% total energy reduction over the lifecycle of a building at reduced costs of 15%.

Producers of bio-based insulators have the advantage that users are both receptive to change and familiar with the products in some capacity. In a study conducted by the Architects’ Council Europe (ACE) for the Low Embodied Energy Insulation Materials (LEEMA) project, 94% of architects surveyed said they would consider using a new and innovative insulation material. An overwhelming endorsement for what remains a niche application in the construction and renovation industries.

Renovations present a key market for producers of new insulation materials. According to the Buildings Performance Institute Europe (BPIE), more than 40% of Europe’s existing homes were built before the 1960s, when there were few requirements for energy efficiency, leading to low insulation levels.

Increasing awareness of the importance of insulation among homeowners is an important consideration. Homeowners may be inclined to, for example, upgrade appliances and install energy saving light bulbs, unaware that retrofitting wall and roof insulation leads to the greatest savings opportunities.

Veronika Schröpfer, lead author on the ACE survey, believes that bio-based insulation materials will continue to move from the niche into the mainstream and that new skill requirements will not present significant roadblocks.

Schröpfer says new building materials are often applied the same way as commonly used ones and manufacturers usually offer training when this is not the case. She states the main concerns involve pricing and regulations in different European countries.

“For architects it is important that a new material has all the necessary certificates and that the product information is transparent, to quickly compare its performance and price with traditional products,” says Schröpfer.

White believes that developers will be receptive to change. “The challenge that ISOBIO will overcome will be to bring [products] to market at scale at the price point that matches their performance to market demand,” he says.

Europe’s construction industry has experienced a turnaround over the last two years. After registering negative growth in 2013, the industry grew by 2.1% this year, and is forecast to grow by a further 2% over the next five years.

Evidence suggests that a growing minority of these builds will involve green projects. A market report from the Word Green Building Council states the proportion of architects and engineers that dedicate 60% or more of their project load to sustainable builds more than doubled over a four-year period — from 13% in 2009 to 28% in 2013.

The report states that increasingly, industry consumers not only demand that new innovations improve performance, but also reduce environmental impact. Fertile territory for the right nature-inspired solutions.

By Angus McNeice