The building industry is responsible for a large percentage of global carbon emissions. Understanding the carbon footprint of building materials is a crucial step to mitigate these emissions.
There are a variety of tools to calculate a building’s embodied carbon footprint, including whole-building life cycle analysis (WBLA) and online carbon calculators.
Glass
Glass is a versatile material that adds both aesthetic and design elements to buildings. The transparent material can let natural light in, reducing the need for artificial lighting, while also limiting heat transmission to reduce reliance on mechanical cooling systems. Glass can be used in walls, windows, doors and more.
While often considered delicate, glass is actually quite durable and long-lasting. In fact, it can last for centuries. Researchers are working to better understand the complex, chaotic structure of glass in order to engineer new materials that could benefit society. For example, they could develop smartphones that are more bendable and less likely to break, or carbon-capturing construction materials that would help mitigate climate change.
As sustainability and resiliency continue to be a priority in the building industry, designers are pushing for a greater consideration of embodied carbon for the materials used in projects. Using recycled glass, for example, saves energy consumption in manufacturing and cuts embodied carbon emissions by up to 50%.
A growing number of architectural glass and fenestration manufacturers are producing Environmental Product Declarations (EPDs) to help architects and building owners evaluate the embodied carbon footprint of their products. One such tool is the National Glass Association’s EPD Calculator for fenestration products. The calculator takes input from glass and framing EPDs to produce Global Warming Potential, or GWP, estimates.
Steel
Steel is a very popular building material because of its durability and strength. However, its production process is extremely energy intensive and creates a lot of greenhouse gases. This is because it requires melting iron ore and blasting oxygen into it at 1500 degrees Fahrenheit. Because of this, the carbon footprint of steel is often a lot higher than other materials, such as glass or concrete.
The carbon footprint of building materials is known as embodied carbon (EC). This is the sum of all the GHG emissions a building produces during its construction. It includes the sourcing, transportation, and manufacturing of all the materials used to construct the structure. Embodied carbon also includes the operational and end-of-life emissions of a building.
To reduce the embodied carbon of a building, designers can choose lower-carbon materials or make changes to existing ones. These include selecting more sustainable insulation, using reclaimed or recycled materials, and designing for material efficiency.
Choosing greener building materials can greatly decrease the embodied carbon of a project. Thankfully, there are many options available in the market. One example is green concrete, which uses industrial byproducts as a substitute for part of traditional cement. This reduces the carbon footprint of concrete without sacrificing its strength or durability. Other green alternatives to traditional concrete are bamboo, which is a fast-growing renewable resource, and hybrid concrete, which uses fly ash as a substitute for some of the cement.
Rammed Earth
One of the oldest construction methods still in use today is rammed earth, which involves compacting soil at its optimum moisture content in formwork and ramming it with a heavy metal hammer. The resulting walls are extremely strong, fire-proof and termite-proof. They also have good insulating properties. They can be constructed with or without cement, depending on engineering and strength requirements. However, cement production is energy intensive and generates significant carbon dioxide emissions, so minimizing the amount of added cement is preferable.
Earthen building can help to reduce the effects of climate change by reducing heating and cooling costs and providing insulation against extreme weather conditions. It is also highly recyclable and has a low embodied energy, which is important when designing a sustainable home or business. The material is also easy to maintain and repair. Avoid using harsh chemicals on rammed earth surfaces, as these can damage the material and strip away protective finishes.
It is essential to choose a contractor or builder that specializes in rammed earth construction when planning a green project. They will be able to offer advice and expertise on the best ways to incorporate renewable energy systems into your home or business, and they will know how to integrate natural light and open space to create a seamless connection with the surrounding landscape.
Aluminum
As insulation and windows continue to be high on building designers’ wishlists, it’s important to consider the embodied carbon footprint of these materials. In fact, as cladding is one of the most significant sources of embodied carbon in buildings (along with brick, cement, steel, and concrete), finding a low-carbon alternative is critical for the climate.
Thankfully, aluminum is an excellent option to reduce a building’s carbon footprint. The energy requirement for aluminium production is high, but this can be put into perspective when considering its longevity and durability. For instance, in the construction industry, aluminium can last for over 60 years, so when spread out across this lifespan, the initial energy requirement isn’t that bad.
In addition, unlike most other metals, recycled aluminium can be used over again without losing its original quality. However, when evaluating the environmental impact of aluminium and other metals it’s important to differentiate between post-consumer scrap and process scrap. Post-consumer scrap is the waste material left over from products that have fulfilled their purpose, such as aluminium cans or car parts. Process scrap, on the other hand, is made from unused product that has never been transformed into a finished product. As such, it should be evaluated separately from post-consumer scrap and given its own carbon footprint, as opposed to being lumped together with primary aluminium and equalized using hydro or coal-based electricity.