According research by the United Nations
, 55% of the world’s population already lives in urban areas. By 2050, that percentage is predicted to grow to 68%. (Some estimates are even higher.) That’s nearly three-quarters of the world—living, working, and playing together in cities.
As the world’s urban populations grow, city planners, developers, construction companies, and construction material manufacturers must answer questions about how to enable construction for those growing populations while supporting sustainability initiatives and complying with local and international building codes.
One answer may lie in a return to wood as a primary construction material. Modern engineering of wood and timber products has created a range of materials that are amazingly strong, light, and versatile. One such product, cross-laminated timber (CLT), stands out as a possible contender for changing the skylines of modern cities
U.S. Borax is a partner in an international research project that’s seeking ways to ensure CLT meets and exceeds standards for strength and safety so that urban policy makers can confidently adopt CLT construction as a solution to their sustainable building needs.
Benefits of CLT buildings
Unlike steel and concrete, wood is a renewable resource with ready supplies provided by generations of sustainable planting and harvesting practices by foresters around the world. And, wood buildings have a significantly lower carbon footprint than buildings made with other materials. In fact, because of its ability to store carbon, wood actually helps reduce the amount of carbon dioxide
in the atmosphere.
However, municipal policymakers who are considering updating construction codes bring up valid questions about wood construction. Flame retardancy is a serious concern for any construction material, and wood materials must comply with the same rigorous standards as other construction materials going into any structure. And, in many highly populous areas of the world, moisture and insects such as termites present constant threats to wooden structures.
The engineering behind CLT addresses these concerns. Sometimes called “super plywood,” CLT is made by stacking and gluing layers of planed, kiln-dried timber. Each layer is placed at a 90-degree angle to the one beneath, and the layers are hydraulically pressed. The resulting panels:
- Are high-strength and reduce the overall self-weight of a building, making them suitable for both low-rise and high-rise structures
- Remain structurally stable in high temperatures (unlike some types of steel)
- Require only about 50% of the energy required to produce concrete and only about 1% of the energy needed to produce steel
Panels can be produced in almost any size, then cut into pre-fabricated building pieces (including openings for doors and windows) that can be delivered to a building site, ready to assemble. The result is less construction time, less site noise and litter, less cleanup—and considerably less on-site groundwork cost.
Building knowledge about the long-term viability of CLT construction
At the fifth Urban Sustainability R&D Congress in Singapore
, attendees from the construction industry, institutes of higher learning, and public agencies gather to collaborate and learn about innovative ways to address the challenges of modern urban life.
At the conference, they will learn about an ongoing research project conducted by Nanyang Technological University called “Understanding Fire Resistance and Termite Protection of Softwood-Based CLT in Tropical Conditions.” Since 2016, the NTU team, led by principle investigator Aravind Dasari, has built a knowledge base for policy makers and developers to use as they evaluate the potential of CLT for construction in Singapore. The aim is to enable understanding of how CLT addresses factors such as flame retardancy, and termites in the tropical conditions that challenge Singapore’s builders.
Experts from U.S. Borax have collaborated with NTU researchers about the choice of boron-based wood treatment products and the method of application to ensure efficacy of the application.
Continuous improvement to ensure sustainable building
Presentation of the research and knowledge base is not the end of the conversation but the beginning. The NTU team anticipates the knowledge base will be used to guide policy and establish guidelines for more extensive use of CLT in Singapore.
From there, other urban centers may reference those guidelines and develop their own plans for expanding the use of this strong, versatile, and sustainable material.
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