written by Rishabh Arora
Offsite and modular construction methods are offering today’s modern builder a smarter way to build by manufacturing parts in a factory before assembling them onsite.
These methods are making strides in the construction industry due to their speed and cost effectiveness, but are they doing so at the expense of the environment?
In this article we’ll make the case for why offsite and modular construction practices contribute toward a greener and more sustainable future.
Lower carbon footprint:
Modular construction results in buildings with a lower carbon footprint compared to traditionally built structures.
According to a study published in the International Journal of Industrialized Construction, modular construction can reduce greenhouse gas emissions by 47% compared to traditional site-built structures. This is mostly due to a combined result of reduced emissions caused during production and efficient material usage.
According to an oft-cited statistic, approximately 30% of all materials at a job site end up as waste. This can occur due to various reasons such as over-ordering or design changes.
In contrast, modular projects put a heavier emphasis on the pre-construction design phase. This involves using the right software tools to design and optimize CAD models.
Modular buildings are produced in a controlled factory environment, allowing the builder to use precise material quantities with minimal waste. Secondly, by using the right software tools, builders are able to optimize their CAD designs and generate precise material estimates.
CNC machinery is used to manufacture the CAD designs. Here, we are referring to the structural components that will form the walls and floors of the building, known as framing.
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sustainable building materials
Steel, wood and concrete are the most commonly used building materials in modular construction. Steel and wood both possess sustainable properties.
The most recyclable material at our disposal today is steel—it is 100% recyclable, and construction projects use it to build structures of all scopes and sizes.
According to the American Iron and Steel Institute, steel framing in North America contains a minimum of 32% recycled steel.
While it is true that significant energy is required to produce steel, this is compensated for in the long run due to its recyclability and reusability.
In fact, certain production methods, such as the electric arc furnace (EAF), use recycled steel along with iron ore to create new steel.
This is another common material used by both modular and traditional projects, typically for residential construction. The only caveat—it is a natural resource that requires responsible harvesting. Much progress continues to be made in terms of sustainable forest management.
The process of harvesting and transforming wood into a construction-ready material requires less energy compared to the production of steel or concrete. Wood naturally stores, or sequesters, carbon for the entire lifetime of a building, helping reduce its overall carbon footprint.
Durability and energy efficiency
Modular construction with wood or light gauge steel framing can lead to sustainable, long-lasting buildings.
Both wood and light gauge steel are highly durable materials and, barring natural calamities, capable of withstanding the forces of nature for long periods of time.
Wood with its natural insulating properties contributes to energy conservation by maintaining consistent indoor temperatures, reducing excess use of heating or cooling systems. Its durability is boosted through modern treatments designed to increase resistance to moisture, pests, mold, and even fire.
What about other biological materials? Project Phoenix, an affordable housing project, has used mycelium in its construction. Mycelium forms a foam-like compound that can be used for insulation purposes.
Cold formed steel, on the other hand, is renowned for its exceptional strength-to-weight ratio, providing robust structural support while being lightweight. Steel by itself is not a good insulator and needs to be complemented with other material, such as fiberglass or spray foam.
In modular construction, efficiency is achieved through standardized processes that lead to consistent quality and faster build times.
Inside the factory, work can proceed regardless of weather conditions, further streamlining construction timelines. Further downstream, the end user is able to benefit from significantly faster occupancy rates compared to traditional site-built structures.
The economic advantages of offsite construction have not gone unnoticed by policy makers. For example, the Canada government-funded Rapid Housing Initiative, which aims to deliver affordable housing quickly, has embraced modular construction.
This preference is based on the ability of modular construction to meet tight deadlines and budget constraints without compromising on quality.
social and health impacts
Last but least, another aspect contributing to the sustainability of offsite and modular construction are the social and health impacts.
Significant portions of the structure are pre-built inside a controlled factory environment, leading to safer conditions for construction workers. In contrast, traditional construction sites are considered to be relatively unsafe due to weather, heights and the use of heavy machinery.
Traditional construction methods can lead to extended periods of disruption due to noise, dust, traffic congestion, and general disturbance. Modular construction on the other hand is less intrusive, as it drastically reduces the time spent on site during the assembly phase. To put things into perspective, a traditional construction project may take 6-12 months from start to finish, while a modular project can be completed within 8-15 weeks.
Offsite and modular construction methods stand at a unique confluence of efficiency, cost effectiveness and sustainability. While modular construction may not answer all of the challenges posed by the built environment, it certainly paves the way for an industry that builds responsibly, keeping both humans and the environment they inhabit in mind.