Calmura Natural Walls, a Canadian social venture, has developed a patented biocomposite wall system that provides healthy, durable and comprehensively protective shells to homes and buildings.
The company uses waste wood from lumber mills, providing circular-economy value in the supply chain, to create carbon-negative building products. The wood is chipped and cast with a lime and clay binder to make long-lasting biocomposite panels and insulating infill, which is then formed into a monolithic building envelope around standard wood framing. The wall system protects from fire, pests, mould and thermal variations, giving visionary homeowners a totally comfortable and safe home for generations.
Monty Chong-Walden, Cofounder/CEO, shares, “Calmura Natural Walls was born from the idea that there needed to be better ways to build the homes we live in and the buildings we inhabit. There are too many cheap materials used for building that lead to poor indoor air quality, end up in the landfill and pollute the environment. Buildings built 100 years or more ago last much better than buildings built in the past 30 years. The inspiration came from a superior building product being used in Europe called Hemp-Lime, Hempcrete, Chaux et Chanvre, Hanf Kalk, Calce Canapa and others. This is a monolithic wall material made from natural materials, much like adobe or cob, but lightweight and more insulating, with a comprehensive list of inherent benefits.”
Calmura is a portmanteau from the Italian words “calce” meaning “lime” and “mura” meaning walls, as it is the lime-based binder that gives the biocomposite many of its fine features and its durability. Monty adds, “Roman lime-based concretes are known as the most sustainable building materials on the Planet, as they have continued to gain strength for 2000 years, and Roman buildings are the longest lasting daily use buildings created. This is inspiring to us and the products we are working on.”
How can biocomposite building materials help mitigate Climate change? Monty explains, “Well, the first thing we need to start doing is using less, therefore making buildings that will last as long as possible is very important. We are not getting that by building faster and cheaper, and then having tons of materials end up in the landfill at the end of a building’s life. Our natural biocomposite wall system is designed to create a very durable structure, like hempcrete, adobe and cob buildings have proven to be, and at the end of the building’s life the biocomposite can be recycled or composted. The goal is to make buildings that will use naturally occurring materials and last as long as possible.”
Storing carbon
Along with this, in Calmura Natural Walls there is the storage of biogenic carbon which would otherwise be burnt, composted or landfilled. By locking these natural fibers in the walls of buildings, the long-term storage will help to mitigate, and even reverse, the carbon emissions due to current materials used that are very carbon or carbon-energy intensive. The whole area of upfront, or embodied carbon, is getting much more attention these days, and some cities are looking at implementing policies for zero-carbon footprint buildings so there are no net emissions from their construction. These targets cannot be met without bio-based building materials. 
Whole Building Life Cycle Assessments (WBLCAs) are a tool being used more extensively which helps to understand what a building’s emissions will be over its existence and help to reduce these impacts as much as possible. These LCAs look at the whole value chain of the building from resource extraction, material manufacturing, building assembly, operation and maintenance, through to disposal or reuse, so they are very telling. In the case where the life cycle costs are also considered, the upfront costs are amortised over a much longer time period for a durable building, thereby reducing the overall costs to the building owner.
Monty sums up, “Essentially, the building industry is a massive worldwide industry and has a large effect on the annual emissions to the atmosphere. Natural, bio-based building products can go a long way to reducing these impacts and creating a healthier environment, both inside and outside our buildings.”
Panel by panel
Calmura is still at a very early stage of product and market development. The product line is centered around a monolithic biocomposite wall system that uses factory-produced permanent biocomposite shuttering panels along with site-supplied foamed biocomposite infill. The 600 mm x 1200 mm panels come in 2 different formats: an Interior Finishing Board that is thinner and more dense, allowing for easier cutting-in of plumbing and electrical, and thought of as a ”drywall replacement”; and, an Exterior Insulation Panel that is thicker with a lighter density to provide better thermal protection on the outside of the wood framing. These panels can also be used in building retrofits, along with mass timber elements and in floors as ceiling to provide thermal and sound insulation, as well as a fire separation layer.
Monty points out, “As we have only had lab-scale production so far, using our product in any buildings has not been possible. We have built an mobile office pod (see attached photo) as a trade show display model.”
Calmura also has enough panels to build a backyard studio office and is looking for the best location to demonstrate the technology with this. As with all products being developed, Monty says that it is hard to talk about competitive pricing. “What we do believe is that we will be price competitive with other high-performance wall systems as these become required in the residential construction industry. In the cases where Whole Building Lice Cycle Analyses (WBLCAs) are used, due to the durability and resilience of our system we believe that consumers will understand the comprehensive value provided by our wall system and it will become the product of choice for health and performance,” he predicts.
As for exports, Calmura has not exported its products yet, but Monty is more interested in exporting the technology to countries around the world, where they will be able to use regional waste resources and local earth elements to create products suitable to their climate and environment. This will also ensure that they have the required certifications for their areas, as well as promote local economies and create meaningful work opportunities for workers in the building trades.
The future plans for the brand is to establish Calmura Natural Walls as the premier wall system and natural building supplier in the world through providing a better, faster and the most healthy and high-performing products on the market. “We want to be a leader in the future of homes that are healthy for the Planet and people,” reiterates Monty.
