Working within the restrictions of a limited carbon footprint can be one of the hardest – but also most rewarding – parts of a modern architect’s role. Whether to suit a large multinational corporation’s sustainability report, to achieve LEED status or similar for a commercial developer, or to build an eco-home for a climate-conscious private client – or even one who just wants to spend less on energy, it’s imperative to keep up-to-date with the latest carbon-neutral and low-carbon building practices and materials.
Whether looking at a project’s structural beginnings, its high-grade finishes, or thinking more holistically about its entire lifetime, there are huge gains to be made with sustainable substitutes and alternatives to traditional materials and techniques.
With research and the resulting innovation in sustainable materials developing so quickly, however, it’s hard to know which option is the right fit for individual projects. Here are a few recently completed projects from the ArchDaily archive, that showcase what’s currently possible.
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As fitzpatrick+partners explain when discussing the architects’ new Bond Commercial Building in a Sydney suburb, Australia, ‘The financial viability of commercial suburban architecture usually results in a carbon-rich building language, favoring financial return over societal responsibility and quality.’ And they’re right. While sustainable construction methods are available, they are not cheap. And it takes only the richest or most dedicated of clients with the right budget to go after them.
But the tide is changing. With the Bond Commercial Building project, fitzpatrick+partners show how it’s possible to employ sustainable building practices – like the use of structural CLT – while staying on the right side of a suburban budget. ‘To be able to build in engineered timber over traditional concrete necessitated a simplicity of form and efficiency of the structure,’ they explain, ‘By utilizing large span sizes with no transfer structures, and working to a singular and repetitive structural solution, The Bond’s design minimized the processing time of the timber structure and therefore costs.’
As part of the ‘Made by NRE’ collective’s collaborative community project to build four new buildings in Eindhoven, The Netherlands, the Body Building was developed to be ‘as circular and sustainable as possible by and for three designers who all work from the human body’, explain the architects Houben / van Mierlo. In front of the cross-laminated timber load-bearing structure, ‘an insulating layer has been built in self-supporting, insulating hempcrete blocks. The bio-based materials provide a breathable shell and a healthy indoor climate, and store more than 200 tons of CO2.’
The Old Ways Are the Best: Teaching Traditional Ceramic Surfacing Techniques
The more architects and their clients who make the hard financial choice to employ more sustainable practices, both in the construction and finishing of their projects, the greater the economies of scale surrounding them, reducing the comparative cost of the materials themselves as well as the cost of the manufacture and craftsmanship in using them.
As the ‘largest terracotta brick tile arched vault structure in India,’ the TARANG Pavilion by The Grid Architects needs ‘no beams, reinforcement or shuttering system’ of any kind, introduce the architects. The construction technique of the curved arches involved ‘spanning without steel and shuttering or the ancillary structures that are typically used to bear the weight of an arch during the building process,’ explained the architects, and employed skilled artisans with in-depth knowledge of the traditional technique to pass on their wisdom and further promote sustainable building.
The project also sought sustainability by focusing on local materials with low embodied energy like natural stone and terracotta tiles. Terracotta tiles are made from natural clay and are a more sustainable surface or facade as they are hardwearing and long-lasting, without the use of additional chemicals or synthetic materials, meaning they’re also easy to recycle at the end of their life. The manufacturing process of terracotta tiles, however, involves baking clay at high temperatures, using a large amount of energy. As part of its own focus on sustainable materials, the CB House in Sabadell, Spain, by Alventosa Morell Arquitectes, approaches this issue by using specifically bio-mass fired ceramics to improve the home’s thermal inertia, as part of its bioclimatic strategy.
Filling the Spaces In Between Natural and Sustainable Insulation Materials
After replacing both the main structural base of a building and its interior and exterior surfaces with more sustainable options, what about the spaces in between? High-performance insulation has always been a product with a sustainable argument – reducing the loss of hard-earned heat – but many types of insulation, such as foam, polystyrene, polyurethane, and polyisocyanurate insulation, are derived from carbon-intensive petroleum or petrochemicals.
As well as using bio-mass-fired ceramics in its surfaces, the CB House also opts for more sustainable cellulose insulation. Made from post-consumer waste paper and requiring only a fraction of the energy to manufacture as other types of insulation, cellulose is often a far more sustainable material to insulate with and can be sprayed or blown into wall cavities, leading to less wastage. Alternatively, with the lowest carbon footprint per sqm across its entire lifetime amongst major materials, labor-intensive straw insulation is one of the least used yet oldest insulation techniques available. Both straw and cellulose insulation, however, are also susceptible to moisture, so additional measures must be considered for protection.
For projects in colder and more damp conditions, like the Brick House in Slovakia, mineral wool insulation might be a safer alternative. Although its production is a more energy-intensive process, the proportion of recycled content in mineral wool can surpass 90%, and it's naturally more flame-retardant and resistant to moisture than cellulose, retaining a high R-value of insulation when wet.
Completing the Circle: Using Recycled and Recyclable Materials
Although many of the alternative construction materials above include fewer environment-harming chemicals and non-renewables, the inherent carbon emitted from their procurement, production, and installation can often offer an opposite side of the argument. Learning to balance the two is an important step for architects looking to make the most sustainable choices, based on each individual project’s restrictions and requirements.
Achieving BREEAM ‘Excellent’ sustainability accreditation, the Roundhouse Works project in London, UK, by Paddy Dillon and Reed Watts Architects paid ‘particular emphasis on reducing the building’s impact on the environment,’ share the architects. Sustainably sourced trees were used to produce the structure’s cross-laminated timber frame – removing 250 tons of CO2 from the atmosphere – while ‘a facade made from recycled railway sleepers saved eight tons of CO2 when compared to other forms of cladding.’
Using recycled materials is a great way to cut down on the carbon emissions of a project, but it’s not always simple to find them. If sustainable materials are not available nearby, a calculated decision must be made between transporting low-carbon materials long distances or finding higher-carbon materials more locally. One practice that will help the total carbon footprint of a project during its lifetime but also beyond, is the use of recyclable materials and practices, too. MVRDV’s Matrix ONE building in Amsterdam, The Netherlands, for example, is designed to be demountable. ‘Simple connections such as screws and bolts allow elements to be detached and reused,’ explain the architects. Prefabricated concrete slabs include no fixed connections, allowing them to be reused at the end of the building’s life, while the Madaster platform the project is signed up to ‘provides a comprehensive material passport system that gives insight into the materials and products used. As a result, over 90% of the building’s materials are available for reuse.
Find these sustainable projects more in this My ArchDaily folder created by the Author.
