Using natural products to develop new building materials

by Ofentse Sefolo
Using natural products to develop new building materials

Walls & Roofs magazine went on a mission to discover some amazing materials being used in the construction of various building projects and realised that older materials have been revitalised in order to be used as viable building materials.

Cork blocks from waste

Yes, the usage of cork is nothing new. It has been used as a beautiful option in the flooring industry. However, there is more to cork than just a viable floor. Studio Bark decided to carry low-budget research to prove how cork can be used in practice, and whether it could provide a viable low-cost, zero-waste method of building for others to use.

They produced cork blocks made from leftover pieces of the wine cork making process. The discarded cork granules are too resinous to be used for wine corks, but are perfect for making insulation blocks. By heating the granules, they expand to fill a mould, and their natural resin is released, binding the granules into a solid block form. The largest sizes currently available are 1 000mm x 500mm x 300mm, and they can be cut to size or milled.

However, a water test proved that the gaps left between the cork granules following expansion are large enough to permit water. Discussions with the manufacturer led to the discovery that the blocks can be compressed further, resulting in a block that is almost twice as dense (a 300mm thick block compresses down to 180mm).

Waste cork has been re-engineerd into high density insulation blocks that are water resistant.

The walls were made of the higher-density cork blocks, cut to size and overlapped in a stretcher bond. The most effective blocks were 1 000mm x 250mm x 180mm (two of these can be pre-cut from a standard 1 000mm x 500mm x 180mm block), as these were easier to handle than the standard blocks, more resistant to lateral loads, and could be fixed together with 300mm insulation screws.

As a result of the permitted development rules and building location, they were required to install a flat roof, which was also more cost-effective and easier to join. A simple series of leftover timber joints was used to provide support for the roof blocks, and helped to stiffen the building. The roof blocks were made of low-density insulation, as it was the best thermally, and would not need to resist moisture due to the Butyl lining. They were able to screw through the blocks and into the frame, which also provided a degree of racking to the structure.

For more information, visit www.studiobark.co.uk.

Innovative Algae Curtain

The Algae Curtain is one of the most innovative demonstrators installed in November 2018 at Dublin Castle, during the week of Climate Innovation Summit 2018. Photo.Synth.Etica was conceived by London-based architectural and urban design firm ecoLogicStudio in a partnered consortium with Urban Morphogenesis Lab, UCL and Synthetic Landscapes Lab at the University of Innsbruck.

The algae curtain can be integrated into existing or new buildings, each one functioning as a photobioreactor.

An “urban curtain”, it captures CO₂ from the atmosphere and stores it in real time – approximately one kilo of CO₂ per day, equivalent to that of 20 large trees. Designed to be integrated into both existing and new buildings, it is composed of 16,2m x 7m modules, each one functioning as a photobioreactor – a digitally designed and custom made bioplastic container – using daylight to feed the living micro-algal cultures and releasing luminescent shades at night.

Close up of the photobioreactor.

Unfiltered air is introduced at the bottom of the facade and air bubbles naturally rise through the watery medium within the bioplastic photobioreactors. CO₂ molecules and air pollutants are captured and stored by the algae, and grow into reusable biomass. Photosynthesised oxygen is then released from the top of each module. The message of this project is one of spatial convergence and connectivity between the financial marketplace of cyberspace and the relative organic molecular transactions in the biosphere.

To learn more, visit www.phtosynthetica.co.uk.

New Cob technologies

Local planning regulations require new construction and renovations that are sympathetic to the historic built environment, much of which is cob and earth. By creating new inexpensive cob technologies that meet building standards, local and national building firms and consumers can meet planning, environmental and financial challenges.

To help meet this challenge, CobBauge will develop, test and establish innovative low-carbon cob technology using local soil and agricultural fibres/waste fibres from the industry. This technology will contribute to the reduction of CO₂ emissions, improved energy efficiency and cost savings over ten years by:
• Creating an inexpensive, well-insulated material, using less than half the heating energy to a cob house compared to traditional building methods (McCabe, 2017).
• Reducing waste by 16 tons, thus saving in landfill costs.
• Requiring minimal transport costs (using local suitable soil), reducing carbon embodied by 4 tons CO₂ per house (Li, 2012).

The CobBauge project’s main aim is to create an economical, insulating construction material with a low environmental impact and to reduce the volume of waste landfilled by using the earth already in place for the construction of the buildings. The other main challenge of this project is to develop the market for cob, both by responding to a demand from the users and by expanding the network of builders able to utilise cob in construction.

To meet these objectives, the CobBauge project will be led in two steps, firstly CobBauge 1, with the schedule of several lines of work:
• The development of new cob: Materials and implementation processes.
• The creation and mobilisation of a network of professional practitioners in construction and cob.
• The communication on the objectives and main result of the project.

These actions will then lead to the training of builders and craftsmen in the production of cob buildings, as well as the construction of a large-scale cob building (CobBauge 2).

Visit www.cobbauge.eu.

Contemporary take on Terrazzo

Altrock is a solid surface material made with reclaimed by-products from the natural stone industries. It’s a contemporary take on terrazzo, an ancient and enduring technique for making stunning decorative and hardwearing surfaces for a whole range of applications.

It combines recycled marble flour, recycled marble chips, chunks of offcuts and broken pieces of beautiful marble slabs. All of these are by-products of local marble manufacturing, and the waste materials from the production of various luxury products and building finishes. The marble is mixed and bonded with a small amount of resin, pigmented in a huge range of custom colours, and cast by hand in slabs of all shapes and sizes.

This product is sealed with a wax oil that dries to a beautiful matt finish. This deepens and highlights the unique veining of the natural stone chunks and provides a durable, waterproof and stain-resistant finish.

Each piece is unique, showcasing the beauty of every chunk of natural stone. Here is a selection of some striking combinations made so far. The stone is a reclaimed material and some colours are rarer finds than others.

Visit www.altrocksurfaces.com.

Sunflower seed leftovers

The potential of sunflower leftover was explored to create new applications and prototypes embedded in sustainable, innovative productive systems. Based on scientific papers, a system of biomaterials using exclusively sunflower by-products has been investigated and designed.

No synthetic binder, no toxic varnish – all the necessary ingredients are extracted from the sunflower crop. The press cake – the remains of sunflower seed after the oil has been extracted – is turned into a water-based glue and heat-pressed into a thin and flexible film resembling leather.

Harvested a month after the flower head, the bark fibres can be separated from the foamy marrow structure. The bark’s fibres are heat-pressed into hardboard while the marrow is shaped into aggregate, a natural alternative to polystyrene. These different biomaterials can be coated with a sunflower varnish to enhance their resistance to water.

The sunflower crop offers a unique range of bio-based and bio-degradable material. Entering the realm of bioplastics, a vast number of applications of what was previously considered waste becomes possible: From a tiny bolt to a large insulation panel, from a bio-board to a smartphone case.

Visit www.vailly.com.

Acknowledgement and thanks go to the following sources for the information contained in this article: www.studiobark.co.uk, www.phtosynthetica.co.uk, www.cobbauge.eu, www.altrocksurfaces.com and www.vailly.com.

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