insulation Archives - IsoBio Project

Home sweet (hemp) home

December 5 is UN World Soil Day. The building industry has thus been called to account for its role in the massive use of mineral raw materials and environmental pollution. One solution comes from the bio-construction sector which draws on unlimited sources of natural materials such as hemp, which is a recyclable carbon sequestrator. But how comfortable is it to live in a hemp house?

Building with wood, straw, and hemp. Biobased materials are seeing ever more use in the construction sector, which needs to become more sustainable as it is one of the major sources of soil, air and water pollution.

“Forty percent of global raw material is consumed by the building industry. Fifty percent of CO₂ emissions into the atmosphere come from the construction sector,” reports Italian bio-construction expert Paolo Ronchetti. Moreover, “Traditional building and insulation materials – of mineral or synthetic origin – are rarely recyclable. At the end of their life they are disposed of in landfills. Therefore, besides having an important environmental impact for their production, they have an equivalent environmental impact for their disposal.”

Biodegradable and from unlimited sources. Instead of exploiting the earth’s crust, and using a process that consumes energy and pollute, the bioconstruction sector can get its materials from the field. Hemp is one of the best examples; it can be grown in crop rotation and improves the quality of the soil. The plant is also a “carbon sequestrator”: it grows very quickly and acts as a carbon store, absorbing atmospheric CO₂ for as long as it continues to exist.

Ronchetti adds: “You should consider that one cubic metre of a brick made from hempcrete – a hemp and lime biocomposite – instead of emitting C0₂, and polluting, it captures 20 kg of CO₂ from the atmosphere. A cubic metre of low-density hempcrete biocomposite, which is sprayed to insulate roofs or subfloors, can remove 60 kg of CO₂ from the atmosphere. So you can imagine – with the volumes and the numbers in the construction industry – how much this virtuous model of building with hemp and lime can fight climate change.”

To note, in the past, industrial hemp was banned in many countries because it was associated with illegal marijuana, from which it differs as the psychoactive compound ‘THC’ is present in proportions of below 0.2%. A thriving industry was consequently stopped. Now hemp farming is flourishing again.

This material also has other advantages. It allows builders to make high-performance envelopes and offers more comfortable, healthy and energy-efficient houses. Furthermore, the traditional building industry has increasingly used synthetic and chemical products that can be toxic and hazardous to human health. Tough low allergen design using natural materials is becoming a new trend.

Northern Italy, Chiari, near Brescia. “In the Po Valley summers are terribly hot and humid. Winters are cold and damp. Humidity rules here!’’ says Sara Bordiga. His husband, Mauro Cogi, longed for an eco-friendly home, and started studying all the available possibilities on the market. Finally, he opted for hemp and in 2015, Mauro and Sara moved into their new biobased house with their child.

“My husband’s choice really surprised me. I had never heard about hemp houses!” says Sara.

Mauro, an engineer, personally followed all the building phases. “The hemp technology works very well. I wrapped the whole structure in this monobloc hemp envelope, thus avoiding thermal bridges.” It’s monobloc because they didn’t use bricks, the hempcrete was sprayed directly onto the structural walls.

As this natural material is porous, it allows the building to “breathe”, avoiding any stagnant humidity. It also keeps a consistent temperature, thus cutting heating and cooling costs.

“Unlike what happens in homes with traditional polystyrene cladding, which doesn’t let moisture out, hemp allows good air exchange. This leads to very dry walls and high environmental comfort,” explains Mauro. “In this house, whose heating and cooling systems are only electric, the maximum power required is 1.8 kW, which is little more than a hair dryer. And with this 1.8 kW I can cool or heat 180 square metres.”

“Zero mould. Zero moisture,” confirms Sara. “And we’re doing well! There is a good level of comfort, we live well in terms of air and well-being.”

Hemp mixed with lime is the usual solution to insulate this kind of building. But European researchers, working on the project called Isobio, went further and developed a lighter but more rigid panel, with improved thermal conductivity. Thanks to innovative biobased binders, whose formula is still a secret, there’s no need for lime. This solution has breakthrough potential in the building sector.

Mike Lawrence, professor at BRE Centre for Innovative Construction Materials, University of Bath, UK, explains: “This material is the major innovation. It is a mixture of the hemp shiv – the woody part of the hemp stock – and it’s been mixed with the thermal setting binder which is also biobased, to make something which is rigid but strong… Much much stronger than you will get with hemp lime, which is much more brittle material. And it’s a lower density than hemp lime, and it’s much more flexible in the possibilities.’’

“The other innovation is a low density, a low thermal conductivity render, and that’s made up with also hemp shiv but it’s very fine. And this is mixed with lime. But because it’s so fine and because of the formulation of the lime, you end up with a render which is very high performance, very low thermal conductivity, much much better than a normal lime render. It’s laid in two layers, it’s got a reinforcement, it’s a sort of plastic grid which is put in between the two layers just to stop it cracking. And on the top – when you put these layers on – you put a standard lime plaster, a lime render which provides the resistance, the full resistance to the weather. Because hemp has the ability to absorb and desorb humidity, on the outside when it’s raining you don’t want that, so you put this out of surface, which will stop the water coming in,” he adds.

“Between the panels we put a fibre insulation. This insulation is made up primarily of recycled cotton, and it’s also got fibres from flax and from hemp,’’ Lawrence concludes.

The researchers are testing these and other innovations in different climates, in Spain and in the UK. They installed their composite panels in two demonstration buildings in Seville and in Wroughton, and now they are monitoring applied solutions. According to their results, they can achieve 20% better insulation performance than conventional materials, 50% less embodied energy and CO₂ emissions, 15% reduction in total costs.

Oliver Style, energy consultant and researcher for Isobio says: ‘’I think that the real innovation is bringing together biobased materials, a lot of which have been used in traditional constructions for centuries, and applying modern solutions to make them fire-resistant, water resistant, to make them bind well and combining all of these different materials in a prefabricated wall system, which can be industrialised. I think up to now a lot of biobased construction has been very small scale, it’s been in the field of people who are very committed to biobased buildings, but it’s quite small scale, quite bespoke. So what we’re trying to do is create scalable solutions that can be built at industrial scale and which can make all of the requirements of the marketplace regarding thermal performance, fire performance, resistant to different weather conditions.’’

The composite panels should enter the market by the end of the decade. These biobased materials are expected to become ever more competitive in the next years, as the European Union requires all new buildings to be “nearly zero-energy”, which means very high energy performance, by the end of 2020.

By Loredana Pianta

27 November 2018

Journalists can download the video teaser and the BROLL [11’, original sound] in HD quality and scripts, free of rights and charge, here: mediacenter.youris.com

Bio-homes to tackle the housing emergency

A new sustainable initiative in Bristol, in the UK, uses bio-based materials to face the need for additional and affordable housing supply

Bristol is at the forefront of high-tech innovation in the UK, named European green capital in 2015. But it is also the second least affordable major British city housing-wise only after London.

Its estimated population is 454,200 people, according to the Office for National Statistics (ONS). Around 10,000 people are registered on the waiting list for a council home. There is a serious housing problem affecting both the young and the old.

To face the emergency, the Knowle West district is testing a new solution that is eco-friendly at the same time. We visited this neighbourhood in the south of Bristol, to discover how a community is trying to make possible a sustainable, affordable housing model using bio-materials.

The initiative, called We Can Make, gathered architects, designers, academics, policy makers, and residents. The result is a prototype house built on the grounds of a community centre, with the cooperation and participation of locals in the construction, plumbing, handmade carved furniture, art, and interior design.

The TAM (Transportable Accommodation Module) was designed and built using bio-materials such as straw, compress straw, and timber. These carbon capturing materials minimise their environmental footprint.

The building is cool in summer and warm in winter, saving hundreds of pounds per month in air conditioning and heating. Actually, as soon as we entered the house, the temperature and the moisture in the environment were right despite the cold weather and rain outside.

According to Dr. Charles Gamble, our guide and head of Innovation at Stramit International, which is part of CooBio company, the TAM uses 90 percent less energy to heat and light when compared to the UK average.

Dr. Charles Gamble, head of Innovation at Stramit International, shows samples of the compressed strawboard panels used in the TAM (By Susan Fourtané)

“The panels are made of compress straw and strawboard framed in timber and covered in clay,” he told youris.com. “Compress straw board has been around for almost 70 years since the technology was invented in Sweden in 1950. The process, also developed in the UK, provided building materials for more than a quarter million houses from the 50s to the 70s after which it became impossible to compete with plasterboard,” he added. These natural retrofitting solutions are also currently being tested at demonstration sites in the UK (Bath) and Spain (Seville) under the EU project Isobio.

Residents who have tested the TAM space overnight have reported that they slept better than usual, which is attributed to a good quality of air in the ambience. External people can rent it through Airbnb, and the income goes to the community centre.

“It’s the breathable nature of the building,” confirmed Finlay White from ModCell, which provided the straw panel systems, when we asked the difference from the traditional Victorian houses in England. “Around the windows in the buildings you don’t get condensation. This is one of the health benefits of using bio-materials,” he explained.

“The mapping of the Knowle West area identified thousands of small plots of land where TAMs could be put to relieve the housing situation for many of the families here who are stuck, because they have no employment or they’re too old. Sometimes you have three or four generations living in a small house,” Gamble said.

“A salary is £23,000 a year. The average price house is 8.4 times that,” added White, while the TAM cost for 36m² is £90,000, with both leasing and hire purchase options.

“What ‘We Can Make’ offers is a model that can be replicated in other regions involving local communities to develop in spaces that they privately own or the council owns, constructing the TAM systems locally to solve housing crisis,” said Gamble.

The team intends to place the houses approximately 200 metres from the community centre, hiring local people to help build the panels creating about 21 jobs in the location.

According to White, there have been identified 1500 potential sites in this area with seven similar more estates in Bristol, and “there are estates like these all over the UK that have the same housing issues.”

A report, We Can Make: civic innovation in housing, was released in October 2017 at the Festival of the Future City in Bristol. The project is in conversation with eight more councils around Britain where TAMs could potentially be built.

By Susan Fourtané

Photo credits: Stramit International

The many faces of hemp

The ecological properties of hemp makes it one of the types of insulation used in construction with the lowest carbon emissions footprint

A relatively recent interest in hemp as a building material responds to a global trend that encourages the development of bio-based products and the reduction of carbon emissions. But its use dates back to many centuries ago.

In China, in 200 BCE, hemp was mixed with lime and tung oil, and used as caulk for junk ships, classic ancient Chinese sailing vessels. It is no surprise these hemp vessels, which sailed by the early Middle Ages, are still in wide use. The permeability of the hemp material that controls moisture similarly to existing wooden elements, makes it ideal for the shipping industry.

In France, we can find another example of its early use in construction in the 6th century. Hemp mortar was discovered in Merovingian bridges where the crop was used to reinforce abutments. The first construction using hempcrete (hemp and lime composite) wrapped around a timber frame was built in 1989 in the same country.

Nowadays, France is Europe’s biggest producer of industrial hemp, and first in the world in hemp-seed production accounting for 59 percent of the global total.

The plant can be grown locally and harvested with minimum input in a matter of months. French Cavac Biomatériaux cultivates hemp and flax. The plantations are located close to its manufacturing site, reducing the company’s carbon footprint. The industrial production of hemp, flax fibres, and shiv, undergo a process of defibering and burling after which they are packed and delivered to the site. “We are a complete hemp chain from the field to the site,” says Valentin Colson, Service R&D of Cavac, which is also member of the European project ISOBIO focusing on eco-materials for low-carbon construction.

The company produces bio-based flexible and rigid insulation panels for the construction industry. “One important point is that the panel is vapour permeable. It is hydrophobic, which means that water has difficulty to penetrate the panel,” explains Colson, offers an excellent long-term mechanical stability, and can also be used to seal and improve the air tightness of the building.

Even though the hemp used in construction is fire resistant, researchers continue to look for better eco-friendly alternatives. “We are working on the fire-proofing of the new panel and try to find an eco-friendly solution to fireproof it,” says Colson.

In the UK, it was illegal to grow hemp between 1929 and 1993, because the plant belongs to the cannabis family. Other places such as Australia, New Zealand, Canada, and the US banned the cultivation of hemp for nearly 70 years due to its connection with marijuana. However, only 0.3 percent of THC (Tetrahydrocannabinol), the principal psychoactive ingredient in marijuana, is present in the strain of plant grown for hemcrete. All the bans are lifted now.

In the US, hempcrete imported from Europe was used for the first time in 2000 in the exterior of a home built for spiritual leader and Sioux elder Ernest Afraid of the Bear on the Pine Ridge Reservation in an attempt to offer the Sioux a return to a self-sustainable and independent life in balance with Mother Earth. However, the construction of a permitted hemp home did not begin until 2010.

In that year, former Asheville mayor Russ Martin and his wife Karon Korp built the first permitted hemp home in Asheville, North Carolina. Back then, they consulted with environmental designer Anthony Brenner, who brought the idea of building with hemp to the couple who was looking for a sustainable, energy-efficient home. After the success with Martin-Korp’s hemp house, Brenner was consulted on many other hemp homes.

Hempcrete panels are used as insulating infill of walls, roof, and under-floor offering great thermal and acoustic performance. Concerns in long-term performance of the plant in construction such as biological degradation, infestation, moisture, structural degradation, or fire “are solved with the presence of hydrated lime,” says Brenner. Among the many benefits of building with hemp, he highlights “carbon-negative, non-toxic, fire-resistant, and mold-resistant.” It provides natural insulation, and it makes for a healthy and safe building site. When a building is demolished, the hempcrete can be recycled and reused in a new building.

In the US, “many states are passing legislation to grow hemp now, which will make it more cost effective. The cost was the biggest hurdle,” says Brenner. This was because before the Agricultural Act signed by former US President Barack Obama in 2014 all the hemp was imported from Europe, mostly from France and the UK.

By Susan Fourtané

Photo credits: Esteban Lopez

14 December 2017

Living in a hemp house

Hemp, a multi-purpose crop that delivers fibres, shivs, seeds, and pharmaceuticals is currently used in insulation materials and bio-composites for a more sustainable construction industry. Russ Martin and his wife Karon Korp tell their story as owners of the first hemp house in the US

Hemp is getting more attention for its multiple uses in sustainable building. In the US, former Asheville mayor Russ Martin and his wife Karon Korp, built the first hemp house in 2010 using crop imported from the UK. They were inspired by Frank Lloyd Wright, an American architect and interior designer who believed in designing structures that are in harmony with humanity and its environment. Wright called this philosophy “organic architecture.”

Karon Korp and Russ Martin Photo source: Karon Korp — Karon Korp and Russ Martin
Photo source: Karon Korp

Since legislation passed in 2014, hemp homes can be homegrown in the US. However, the industrial cultivation of this plant is still in its infancy. There were only 4,000 hectares planted in 2016 in contrast to 33,000 hectares of industrial hemp grown in Europe in the same year.

“Hemp is a great option and a sustainable product that should be more widely accepted and used,” says Karon Korp, who together with her husband, lived for six years in their hemp house in North Carolina. “Designer Anthony Brenner worked with us to help create the home and its features, and brought the idea of building with hemp to us.” youris.com asked Korp to share some more details from their life in the hemp house.

What was your main motivation for building a hemp house?
We wanted to do something that had not been done before, in a healthy, green way that was more sustainable for our planet.

Do you still live there?
We sold the home last year, the first of its kind in America. Though the space was beautiful and we enjoyed living there very much, it was at 3,500 feet (around 1,060 metres) elevation, almost the top of the mountain. Our lifestyle and work commitments found us in town most days and we decided to simplify our lives a bit by moving to a more convenient neighbourhood.

How was living in the hemp house in the mountains like?
It was a sanctuary almost on top of the mountain, views of mountains and nature all around, filled with light in every room, ample wildlife – lots of black bears!

The first hemp house built from hempcrete in the U.S., belonged to Russ Martin and Karon Korp. It was their hemp home from 2010 to 2016. Photo source: Anthony Brenner — The first hemp house built from hempcrete in the U.S., belonged to Russ Martin and Karon Korp. It was their hemp home from 2010 to 2016.
Photo source: Anthony Brenner

Can you comment on how the insulation and air-purifying properties were when you lived there? How do they compare to your previous houses?
The home is 3,000 square feet (around 279 square metres), and the insulating factor of the hemp proved quite effective, even at the higher elevation where weather could be colder and more severe than lower elevations. Our electric bill was routinely below average for homes of similar size. As for the air-purifying properties of the home, I would say we were less prone to allergies while living there for six years.

Could you tell us more about other eco-friendly materials that were used in the house?
We had walls made out of a product from recycled paper. They are structurally more sound than traditionally framed walls, and on the exterior they are covered with a magnesium oxide board finish. We used recycled building materials throughout the home: flooring, windows, vanities. We used natural finishes, and NO VOC (volatile organic compounds) stains, and paint. The hemp was fire retarding.

What about the costs of living in a hemp house?
The cost of our house average monthly energy bill was $100 (around €85) for a 3,000 square feet (around 279 square metres) home. Moreover, we saved 25 percent on our homeowner’s insurance after moving into the hemp house.

Can you also share the price of the house when you sold it?
The house sold for $685,000 (around €584,000) in May 2017.
Do you think hemp could be the preferred material in the future of the construction industry?
While I don’t think it will ever completely replace traditional methods and materials, industrial hemp could revolutionise the building industry, and provide a new agricultural product that would support farmers and rebuild their industry.

By Susan Fourtané

14 December 2017

Rigid Insulation Panel from Hemp

Cavac Biomatériaux is a subsidiary of the French Agricultural Cooperative Cavac, and specialises in the production of biobased insulation products for the building market. Within the ISOBIO project they have developed a new product: a rigid insulation panel made of hemp.

The panel is composed of a commercial hemp shiv grade bonded using a specially formulated thermosetting bio-based binder, developed in collaboration with UR1. The panel manufacturing process has been validated on existing industrial tools and panel prototypes have been installed at ISOBIO demonstrators.

Functions

The rigid panel can be used for internal or external insulation, or as a substrate for renders or plasters. A tongue and groove system has been developed for easy installation and to prevent thermal bridging.

The insulating panel offers a low thermal conductivity and embodied energy while maximising the moisture buffering value and mechanical properties. Research on additives showed that improved water repellence and fire performances can be obtained.

Impact

This product brings a new valorisation to hemp shiv aggregates (a byproduct of the hemp transformation). The biobased binder offers an eco-friendly and harmless alternative to formaldehyde and isocyanate adhesives.

The compatibility with dry manufacturing processes also significantly reduces the embodied energy when compared to existing wet processes.

What about GMOs in our homes?

Adopting biobased materials in home building can slash construction costs, but is Europe ready to put aside its fears about GM products?

One of the main contributors of CO₂ emissions are the homes we live in. In the EU, buildings are responsible for 36% of CO₂ emissions and 40% of energy consumption.

Researchers argue that, compared with using traditional mineral-based materials in construction, “eco-friendly” durable composites can slash by half the embodied energy and improve insulation by 20%. This means better efficiency but also reduced building costs. The hitch, though, is what biobased materials to use. And is it advisable to avoid GM products?

GMOs, genetically modified organisms, are among one of the most controversial topics in agriculture. Experts have divergent views. “The current EU GM regulation is very much outdated and dysfunctional. Plant science has in the last 15 years made enormous progress,” says Stefan Jansson, professor in the Department of Plant Physiology at Umea University, Sweden. “Gene transfer from GM crops to wild relatives is no more or no less risky that gene transfer from all other (domesticated) crops to wild relatives, which no-one ever cared about.”

It is important to ask why we are shying away from GMO products, argues Jonathan Jones, a professor at The Sainsbury Laboratory, UK, working on a project to test modified potatoes and their resistance to blight. “The GM method is totally benign and totally safe and it enables you to move genes that do different things from one plant to another,” he says.

However, some groups pioneering the use of natural products in construction have opted to avoid GM materials.

It is the case of the European project ISOBIO, which is developing innovative solutions to boost the use of bio-based materials in construction. They do not use agricultural waste from GMO plants.

Moreover, the companies that joined the consortium source local products, which will be easier to recycle being part of their landscape. Manfred Lemke, from Claytec, a Germany-based developer and producer of clay, points out that they take their straw from the fields around the factory. “Cavac, another partner in the project, sources hemp from local farmers near its base France, rather than importing materials from overseas. ‘Think global act local’ for supply chains, it avoids contamination and further risks of anonymous, global supply chains,” he adds.

“Recycling agricultural waste sounds like a positive aim. If GM crops were involved, then the potential harms would need to be thoroughly, and independently, examined,” argues Liz O’Neill, director of campaign group GM Freeze. “Even the tiniest change to the genome can have unexpected impacts, both within the organism itself and in the ecosystem into which it is introduced, ” she says. According to O’Neill, EU labelling laws help consumers identify products with GM ingredients and avoid them if they wish.

In this context, EU Ecolabel, a voluntary labelling scheme, certifies, among other things that products do not originate from genetically modified organisms.

However we approach the GM issue, looking forward to further research on it, it is certainly important to brand any products containing GMOs to allow consumers to make their own decision.

By Sam Edwards

Photo credits: Redd Angelo

4 October 2017

On the way to demonstrating the benefits of bio-based materials for the construction sector

ISOBIO aims to develop new bio-based insulation panels and renders, and to scale them for mainstream adoption by the building and construction industry. The focus is now on the challenging demonstration phase.

ISOBIO innovation partners are bonded by a unique goal: to design a bio-based insulation material with the right chemical and mechanical properties to tackle water absorption, fire resistance and moisture buffering while ensuring high thermal conductivity. These essential properties provide material resistance as well as indoor wellbeing and confort.

In February 2017, partners convened on the premises of TWI in Cambridge for their mid-term project meeting. It was an opportunity for them to assess the research and preliminary prototyping, and to outline the regulatory and market challenges ahead. Following this meeting, the final composition of the bio-materials is now just around the corner.

As part of their research, the Universities of Bath and Rennes have examined the characterisation of bio-materials and the development of composite materials (including the insulating core and the composition of the external layer). These research results form the basis for the technical developments by industrial partners Cavac, BCB and Claytec. The innovation lies in the feeding of knowledge from the labs into the industrialisation phrase.

After testing and prototyping, ISOBIO is poised to reveal a bio-based product design offering all the right properties for a greener building and construction industry: high insulation, low embodied energy and carbon, and hydrothermal efficiency.

17 March 2017

A raincoat for our houses

From the use of Gore-Tex-like waterproof fabrics to the development of “breathable” bio-based materials, the construction industry is chasing breakthrough solutions to insulate buildings and keep living areas free from damp and mould

Today, one of the new challenges for the construction industry is the use of textiles, coming from the clothing and footwear industries. Gore-Tex-like membranes, which are usually found in weather-proof jackets and trekking shoes, are now being studied to build breathable, water-resistant walls. Tyvek is an example of one such synthetic textile being used as a “raincoat” for our homes.

Camping tents, which have been used for ages to protect against wind, ultra-violet rays and rain, have also inspired the modern construction industry, or “buildtech sector”. This new field of research focuses on the different fibres (animal-based such as wool or silk, plant-based such as linen and cotton and synthetic such as polyester and rayon) in order to develop technical or high-performance materials, thus improving the quality of construction, especially for buildings, dams, bridges, tunnels and roads. This is due to the fibres’ mechanical properties, such as lightness, strength, and also resistance to many factors like creep, deterioration by chemicals and pollutants in the air or rain.

“Textiles play an important role in the modernisation of infrastructure and in sustainable buildings”, explains Andrea Bassi, professor at the Department of Civil and Environmental Engineering (DICA), Politecnico of Milan, “Nylon and fiberglass are mixed with traditional fibres to control thermal and acoustic insulation in walls, façades and roofs. Technological innovation in materials, which includes nanotechnologies combined with traditional textiles used in clothes, enables buildings and other constructions to be designed using textiles containing steel polyvinyl chloride (PVC) or ethylene tetrafluoroethylene (ETFE). This gives the materials new antibacterial, antifungal and antimycotic properties in addition to being antistatic, sound-absorbing and water-resistant”.

Rooflys is another example. In this case, coated black woven textiles are placed under the roof to protect roof insulation from mould. These building textiles have also been tested for fire resistance, nail sealability, water and vapour impermeability, wind and UV resistance.

Production line at the co-operative enterprise CAVAC Biomatériaux, France. Natural fibres processed into a continuous mat (biofib) – Martin Ansell, BRE CICM, University of Bath, UK

In Spain three researchers from the Technical University of Madrid (UPM) have developed a new panel made with textile waste. They claim that it can significantly enhance both the thermal and acoustic conditions of buildings, while reducing greenhouse gas emissions and the energy impact associated with the development of construction materials.

Besides textiles, innovative natural fibre composite materials are a parallel field of the research on insulators that can preserve indoor air quality. These bio-based materials, such as straw and hemp, “can reduce the incidence of mould growth because they breathe. The breathability of materials refers to their ability to absorb and desorb moisture naturally”, says expert Finlay White from Modcell, who contributed to the construction of what they claim are the world’s first commercially available straw houses, “For example, highly insulated buildings with poor ventilation can build-up high levels of moisture in the air. If the moisture meets a cool surface it will condensate and producing mould, unless it is managed. Bio-based materials have the means to absorb moisture so that the risk of condensation is reduced, preventing the potential for mould growth”.

The Bristol-based green technology firm is collaborating with the European Isobio project, which is testing bio-based insulators which perform 20% better than conventional materials. “This would lead to a 5% total energy reduction over the lifecycle of a building”, explains Martin Ansell, from BRE Centre for Innovative Construction Materials (BRE CICM), University of Bath, UK, another partner of the project.

“Costs would also be reduced. We are evaluating the thermal and hygroscopic properties of a range of plant-derived by-products including hemp, jute, rape and straw fibres plus corn cob residues. Advanced sol-gel coatings are being deposited on these fibres to optimise these properties in order to produce highly insulating and breathable construction materials”, Ansell concludes.

By Chiara Cecchi

21 December 2016

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

Beyond research, towards the market

ISOBIO is emerging from the research phase and taking its first steps towards its target market. Bringing innovation and research outcomes to the attention of experts and stakeholders is essential to tackling some of the possible challenges in the industrialisation phase.

Against this backdrop, ISOBIO innovation partners held a workshop on 14 September this year at the University of Bath. The aim was to stimulate discussion about bio-based insulation materials and the associated environmental and LCA issues. The workshop took place alongside an event held by the Alliance for Sustainable Building Products (ASBP), focusing on embodied carbon issues and providing useful insights and strategies for reducing it.

ISOBIO had the opportunity to share knowledge about major topics such as life cycle assessment and cost analysis, key results of demonstration actions (including, carbon sequestration, waste minimisation, efficient energy and raw material use) as well as a case study of a nearly-zero energy residential building made with straw bales and timber. This highlights a strong link among bio-based building systems, energy efficiency and indoor comfort, allowing strong connection between the bio-economy and energy sectors to be created. The workshop was also an opportunity to hear about ASBP activities associated to the challenges of applying LCA and Life Cycle Costing (LCC) to external thermal insulation composite systems and to embodied carbon policies and decision making tools.

LCA and LCC are essential aspects that can bring research outputs closer to the target market. Engaging with stakeholders, sharing knowledge and best practices is key to stimulating stakeholders’ acceptance of the designed bio-based material, which aims to turn a niche innovation into a mainstream product of the construction sector. ISOBIO is taking its first steps in this direction and, little by little, it will need to address all challenges of industrialisation, firmly drawing on its particular strengths and exploiting the opportunities ahead.

13 October 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

Back to basics – Setting the path towards making bio-based materials mainstream: opportunities offered by nature are facing cultural, technical and market challenges

ISOBIO aims to develop new bio-based insulation panels and renders, and to scale them to mainstream adoption in the building and construction industry. A purpose driven by a common vision: the less we intervene on materials, the more we achieve.

In ISOBIO, innovation is coming straight from nature: fibres and straw are some of the raw materials at the core. Scientists and stakeholders do acknowledge this but demonstrating this vision presents a number of research and technical challenges. This could be a niche market, and a highly eco-friendly one.

The University of Rennes hosted the first regional stakeholder workshop on 4 February 2016. It brought together academia and research stakeholders to tackle the main challenges of the project’s objectives and to explore opportunities offered by bio-based construction materials.

Multifold barriers were identified that need to be overcome if bio aggregates are to be widely adopted across the construction sector: technically, the challenge is to do with confidence in producing raw materials and meeting the technical standards for natural insulation materials. Scientifically, water repellence and fire resistance are essential issues under the microscope.

Behind the uptake of bio-based aggregates, there is an even more substantial question: is the market ready for them? This raises the issues of public perception and market penetration. Persuading users that they can safely benefit from bio-based materials may be as challenging as reaching the market penetration level required to replicate the solution developed while keeping the same quality level of the final product.

The workshop enabled a wide range of research and academia stakeholders to engage directly with one another and explore these challenges, in view of working together towards ISOBIO’s aim of widespread adoption and design of a bio-based product with high-insulating properties, low embodied energy and carbon, hydrothermally efficient, greening the building and construction industry.

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