Building materials that are making construction more sustainable

Building materials that are making construction more sustainable

Sustainable building materials are essential for greener buildings. Indeed construction and demolition waste makes up about 40% of the total solid waste stream in the U.S. and about 25% of the total waste stream in the European Union, according to the United States Green Building Council (USGBC). Sustainable building materials can help us reduce this large amount of waste and the negative effects of greenhouse gases.

One important factor in the building’s life cycle is selecting sustainable building materials. Here are 5 sustainable materials that are making waves in the construction industry:

Precast concrete

Precast concrete panel provide stellar performance and efficiency.  Concrete is one of the most common building materials in the world because of its durability and strength, but precast concrete is proving itself to be one of the most sustainable building materials. Precast concrete is produced in a controlled manufacturing plant and then transported to a site already reinforced and finished according to specification, which eliminates the need to cast concrete on-site and shortens the installation time. This makes precast concrete building less disruptive to the site environment, producing less construction debris, dust, noise, and pollution.

The materials used in precast concrete can be locally sourced, including the cement, the coarse and fine aggregates, and the steel, which reduces shipping waste and overall carbon footprint. Precast concrete units can be disassembled in an existing structure to be moved or reconfigured, and the concrete can be crushed and reused as aggregate.

Regular concrete usually has a thermal resistance rating of about 0.11 per inch of thickness, while precast concrete can provide double the resistance—0.22 per inch of thickness. Precast concrete can be dense or lightweight, giving builders options when deciding on the level of thermal insulation needed. Concrete itself is an effective fire barrier. Precast concrete wall panels are capable of providing a two- to four-hour fire rating. And they stay intact even in hot chemical fires. Precast is also resistant to rain penetration and wind-blown debris, offering protection from storms and harsh weather.

Cross-Laminated Timber

CLT has the potential to substantially reduce the carbon footprint of new buildings by replacing structural concrete

Alternatives to concrete, like cross-laminated timber, are also increasingly popular. While wood has been used in construction since the beginning of time, CLT has joined the ranks of the most sustainable building materials. CLT is a solid wood panel made from layering boards in alternating directions, bonded together with structural adhesive.

The alternating fibres and solid composition of CLT give it the potential to substantially reduce the carbon footprint of new buildings by replacing structural concrete. It’s lightweight, strong, and fire and earthquake resistant. Dalston Works—the world’s largest building constructed out of CLT—weighs approximately one-fifth of a concrete building of the same size. And on top of that, it was completed an estimated eight months faster than if traditional building materials had been used.

All CLT components of Dalston Works were prefabricated and then transported to the construction site, including floors, walls, stairs, and shafts. This improved the work environment onsite, meaning less noise, dust, and waste. Using prefabricated CLT components, construction workers could put up a whole floor in a week, allowing CLT projects to be built larger and faster.

Reclaimed Wood

Building with reclaimed wood prevents unnecessary logging and reduces manufacturing and transportation-related greenhouse gas emissions, according to the National Resource Defense Council. Reclaimed wood is a sustainable building alternative to harvesting new lumber.

Wood that was harvested and milled decades ago and that has been in use for years as barn siding, wood pallets, and railroad ties and trestles has been exposed to the elements, which increases its stability. Also, reclaimed wood is mostly dense-grain, old-growth material, so it’s stronger and more durable than new lumber from younger, less dense trees more prone to warping and bending.

The Singapore Green Building Council did a carbon impact study of the product and found that, even accounting for shipping across the Pacific Ocean, this weathered wood is carbon negative. The low moisture content of reclaimed wood eliminates the need for kilning and drying, which saves time and energy. The wood for the fences is sustainably harvested Douglas fir and Ponderosa pine.

Steel

Building with steel can help you achieve green building certifications and sustainability goals.

Steel has been a popular choice for construction projects long before the green building movement began, but the industry is constantly adapting and advancing. Over the past 25 years, the steel industry in North America has reduced energy intensity and greenhouse gas emissions by more than a third, making the production of steel more sustainable and reducing its environmental impact. It’s often used in poolsdrains, and even in steel conduit.

Steel helps builders and designers meet steel building codes and earn multiple credits for green building rating programs like LEED or the Living Building Challenge. This is because steel can be easily assembled and disassembled, making it surprisingly recyclable: Any steel product can be recycled into another.

Virtually all steel products contain at least 25% recycled content already, with some products containing up to 100% recycled material.

Because of its recyclability, using steel reduces construction and demolition waste because many steel construction products are made off-site. They are pre-manufactured, pre-cut to finished size, or fabricated to precise project specifications before they are shipped to the job site. Steel scrap generated onsite can be easily recycled. In fact, 60 to 80 million tons of steel scrap are recycled into new North American products every year.

Terrazzo

Terrazzo is a mosaic style of flooring where small pieces of marble or granite are set in polished concrete or epoxy resin. With simple maintenance, these floors can last 40 years or more without losing their brilliance. Modelled after 20th century Italian work, original terrazzo was set in cement, but now 90% of terrazzo floors are made with an epoxy resin.

Known for design flexibility and remarkable durability, using this sustainable building material may carry a higher upfront cost, but its durability and life expectancy often make it the most affordable option in the long run compared to life cycle costs for carpet, porcelain, or other flooring materials. A terrazzo floor might cost five times more than carpet, but Bateman says you will probably have to replace that carpet six times during the life of one terrazzo installation, making this classic floor a modern sustainable building material.

Terrazzo is poured in place, so there’s a lot of colour and design flexibility, and the flooring is one seamless surface, which alleviates hygiene issues. These floors are very easy to clean and can be used in high-traffic areas like schools, stadiums, and airports.

Further information

 

April 9, 2019
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