Climate, Carbon and Cork: Using ThermaCork to Decrease Embodied Carbon in Your Build

ThermaCork continues to be a very popular product with Small Planet Supply customers. Between the natural beauty and impressive insulative value, there is certainly a lot to love about this 100% natural product. One great thing not everyone is aware of though is how ThermaCork has a less than zero carbon footprint. This negative carbon footprint is an important part of the fight against climate change and ThermaCork is a great way to help bring down the overall carbon footprint of a building. Read on and take a deep dive into the importance of carbon footprints, the history of cork in building and where it comes from.

Greenhouse Effect

According to the 2018 report by the IPCC, Global Warming of 1.5*C, we are in the middle of a climate crisis. Since the dawn of modern man there has been a need to consume fuel to heat and power our way of life. Much of this fuel is dug from the ground or pulled out of the environment in other ways, and almost all of it is primarily made of carbon. When this carbon rich fuel is used it releases carbon dioxide to the atmosphere, this a major contributor to the greenhouse effect. The main contributor to climate change, the greenhouse effect is characterized by the way accumulated atmospheric carbon dioxide interacts with visible light and radiant heat. Carbon dioxide is effectively transparent to ultraviolet light, and translucent to opaque to infrared light. The light that reaches us from the sun is mostly in the ultraviolet spectrum, so can pass through the accumulated layers of CO2 and other greenhouse gasses in the atmosphere. As ultraviolet light reaches the surface of the earth it is reflected/radiated as infrared light, or heat energy, and is less able to pass through the layers of greenhouse gasses the more accumulated they become. This has the effect of raising the overall temperature of the earth, which can lead to drastic changes in climate and threatens to wipe out many of the more sensitive environments in our world.

Building Materials and Embodied Carbon 

Contributors to Construction Industry Carbon Emissions

As the population continues to grow globally, there will be even higher demand for energy. Much of this demand for energy will come in the form of housing and the manufacturing processes tied to the construction industry. In fact, buildings are currently responsible for 39% of global energy related carbon emissions. With 28% being from operational emissions i.e., heating and cooling and electricity usage, which we call operational carbon. The remaining 11% comes from the materials and construction. When we talk about the energy and fuel consumed during the production of materials and construction of homes, we represent it as embodied carbon. This is the sum of all the greenhouse gas emissions resulting from mining, harvesting, processing, manufacturing, transportation, and installation of building materials. As the manufacturing and construction industry accounts for nearly 2/5ths of global emissions and is only set to increase that amount if left unchecked, there stands a great opportunity to make a major global impact by shifting towards more efficient buildings and construction processes.

What are some of the ways we can work towards reducing the embodied carbon in the building sector? Can we do this without sacrificing performance in other areas like thermals and energy? This is an important question to ask because if lower embodied carbon comes at the cost of building performance, requiring more energy to operate, then the net effective carbon emissions are not significantly reduced. Another consideration is the end of life impact a material will have. Products that can be easily reused or recycled efficiently are desirable in this front. If a material is difficult to repurpose and the disposal means are harmful to the environment, then it will have a greater EOL impact on carbon emissions. These are the questions we will need to be asking at every step in the process if we are to make a significant impact to carbon emissions. ThermaCork is one such natural resource which can play a major role in working towards these goals.

Cork: A Versatile Solution for Reducing Embodied Carbon in Buildings

Fiberglass Batt Insulation Could Be Replaced Easily With ThermaCork Boards, reducing the amount of embodied carbon in your building project

One of the areas to focus our attention on for reducing embodied carbon in buildings is the insulation. A 2010 study and subsequent article by Alex Wilson, “Avoiding the Global Warming Impact of Insulation”, identified the effect that insulation can have on global warming. The study was conducted to determine the amount of time a highly insulated wall assembly would need to be in use to more or less “pay back” (in reduced energy use carbon emissions) the global warming impact of the insulation itself. The study focused its attention on two major factors of global warming potential, the embodied carbon of the material itself, and the impact of the blowing agents (chemicals) used, if any. Unsurprisingly materials that don’t use any blowing agents, like dense pack cellulose and fiberglass batt, have a very low payback timeline, whereas products like XPS and HFC-Blown Spray Polyurethane have significant payback times. For example, a 1-inch layer of XPS added to a wall has a 36-year payback time!

What we can observe from this is that if we are building highly insulated homes partially motivated to mitigate global warming, we should avoid using insulation materials that are associated with a much higher global warming potential. While there are several conventional alternatives that meet this criterion for lower global warming potential, such as mineral wool, fiberglass batts, or water blown SPF, there remains another option that can offset even more embodied carbon while still maintaining a relatively high thermal resistance. That option is cork, specifically ThermaCork available through Small Planet Supply.

Cork’s Place in History and Construction

Egyptian Sandal with Cork Sole

Construction of “Convento de Santa Cruz da Serra da Sintra” (Sintra, Portugal) , established in 1560, included cork bark to insulate the interior walls and windows.

The bark of the cork oak tree, Quercus Suber L., has been used by humans in some form or another for millennia. Most recognizable today for its uses as wine stoppers and office billboards, cork as a material has been seen in many products going as far back as the ancient Egyptians, and perhaps the earliest uses for construction and insulation belonging to the Greeks and Romans. This 100% natural product is simply the bark of the cork oak tree that has been cultivated and harvested for many generations. It is thought that the Greeks were the first to discover that stripping the bark from the tree encouraged a new higher quality cork to regrow in its place. This makes cork bark a highly renewable resource, especially considering that a single cork oak tree can live for over 200 years. In its lifetime, a cork oak tree can be harvested every 9 years, providing enough cork bark to make upwards of one hundred thousand cork stoppers in its lifetime. Since the trees never need to be cut down, they can continue to remove carbon from the atmosphere via photosynthesis. This carbon is used as building blocks for the trees, and indeed all plants, to grow. When carbon is removed from the atmosphere and stored in organic matter which we then use, it is considered Sequestered Carbon and has the net effect of lowering the overall global warming potential of the products it is used for.

Look familiar? Armstrong cork & insulation Company (now Armstrong flooring) marketed their Armstrong Corkboard insulation in this 1927 advertisement.

Cork bottle stoppers and post-it boards might not make a significant impact on embodied carbon, but in the late 1800s a process was discovered that would be able to turn waste cork granules into a useable product. By the process of agglomeration, rigid expanded cork boards came into prominence and greatly increased the uses for cork. This would later benefit the cork industry and communities centered around the maintenance and harvesting of the cork oak forests. In the early 2000s the cork industry started to see a reduction in cork wine stopper demand due to competition from manufacturers of metal and plastic screw caps. The ability of the industry to swiftly change course has been a greatly positive impact on renewed interest in cork as a building material, and as a sustainable economic and ecological model. Today we see cork used in buildings in many applications, from beautiful natural tile flooring to ceiling panels that help with acoustics.

Benefits of Cork as an Insulation for Buildings

Of particular interest to the green and high-performance building world is expanded cork insulation. Earlier we mentioned the process of agglomeration, this process allows us to take what would otherwise be waste material and turn it in to a useable product. When cork bottle stoppers are punched out of bark strips, about 60% – 75% of the cork remains that cannot be used for wine stoppers. This leftover bark is broken down into smaller granules to be used for various products. For flooring and similar products, these granules are mixed with glues and resins and sliced into a finished product. Making expanded cork insulation is a completely different process. The cork granules are loaded into large metal forms, or autoclaves, where they are exposed to superheated steam. The heating process expands the cork granules and activates a natural binder present in the cork, called suberin, which binds the now expanded granules together and takes the form of the mold. The resulting billet is then sliced to make insulation sheets in various thicknesses from ½ inch to upwards of 12 inches.

ThermaCork Insulation Boards are a great replacement for XPS and other foam insulation

These all-natural insulation panels make a great replacement for XPS, which has the highest GWP impact on a building. Like all insulation products, cork works by trapping air in thousands of pockets to act as resistance to thermal energy passing through. At R- 4/inch, Thermacork falls right in line with some of the well-known insulations being used, such as EPS foam and open cell SPF spray foam. It even outperforms mineral wool insulation’s thermal resistance properties. These alternative insulation products are becoming more popular in part because of their lower impact on a building’s embodied carbon, but Thermacork is the only one that has a net effect of lowering a building’s total embodied carbon. This is due to how much carbon is sequestered in the bark granules, making it carbon negative, and how sustainable the production of cork insulation products is, which does not involve any added chemicals.

ThermaCork: Fighting Back to Reduce Embodied Carbon

Portugal Is The Largest Grower of Cork Oaks In The Mediterranean

Reduced embodied carbon is not the only benefit cork brings to the industry. The cork oak tree grows in the Mediterranean Basin, and especially well in the southern regions of Portugal, which is responsible for a considerable portion of the region’s cork production. These cork oak forests have been tended to for generations and as a result they play a major social and economic role in their areas by providing jobs for the community, as well as bringing a wealth of biodiversity to the area. By carefully managing these forests, which the Portuguese call Montados, they have been able to create an extremely sustainable ecosystem that gives back in many ways. Additionally, there is no waste in the cork industry, everything gets used in some capacity. Acorns from the cork oak tree are used not only for propagation, but also as food for the native fauna as well as being used for making cooking oils. Branches from pruning are used for firewood or charcoal, and the tannins and natural acids in the wood are harvested for use. Even the dust of the cork bark is used as fuel to heat the steam for the agglomeration process. All of this works together to reduce the carbon footprint of cork products to be carbon negative.

Even the end-of-life carbon footprint for cork is miniscule, as cork is highly recyclable and 100% biodegradable. When you look at each of these details compared to the other insulation products you start to see how ThermaCork is truly the greenest rigid insulation. When used as continuous exterior insulation, ThermaCork helps get rid of any thermal bridging present in the structure. Furthermore, unlike expanded foam products, ThermaCork does not off gas any chemicals or reduce in thermal efficiency like some foam insulations, and Thermacork is both hydrophobic and vapor permeable, which helps to keep your structural sheathing dry and free of rot.

Next time you’re looking at the insulation aspect of your build or remodel, keep ThermaCork in mind. ThermaCork is not only great for the environment, but it also supports a multitude of economies from the growers to the suppliers. Small Planet Supply stocks many thickness sizes of ThermaCork and can supply large amounts for external insulation projects. Visit the ThermaCork page of our website to learn more or call today to place an order.