As you start the process of building your new house or Accessory Dwelling Unit (ADU), don’t dismiss a modular approach. Modular construction is a house, ADU, or other type of building built off-site in a factory and transported in pieces or a complete building to its permanent location (5). Currently only 2% of new single-family homes in the United States are built in factories (7). However, there are many benefits to factory-built structures that many people don’t consider.
Modular buildings have a shorter construction time and lower costs than traditional construction with estimates of up to 60% faster timelines and cost reductions of around 30% (6). Some sources have even calculated an 80% cost difference between modular and stick built homes (7). They not only are cheaper and faster to build but they also can be more environmentally sustainable. Research has shown that modular building has multiple environmental benefits including waste reduction, a smaller carbon footprint, and greater energy efficiency.
Waste Reduction
Modular buildings are almost completely constructed in controlled factory environments. As a result, they contribute far less waste than a traditional construction process. Conventional construction is a large source of waste. According to the Terner Center, a 2,000-square-foot building generates up to 8,000 pounds of waste from construction (2). Building in a factory can reduce waste in a variety of ways. For one, there are more opportunities to recycle and reuse discarded materials in different modular buildings in the factory. Second, the controlled factory environment leads to more opportunities for digital modelling and precise material usage. Third, building in factories stops waste from accumulating due to weather-related damage (2,5,8). This is especially important in the Tahoe region where snow is a major factor in when construction can happen and where surprise snowstorms can happen well into the spring. Due to these factors and others, the Modular Building Institute reports that modular construction can produce up to 90% less waste than conventional construction (1).
In California, it is estimated that solid waste from construction and demolition account for 22% to 26% of all of California’s waste disposal (9). Modular building is one way to help reduce this waste.
Fewer Emissions
Not only does building modular help reduce waste, but it also lowers greenhouse gas emissions. Construction is a large contributor to carbon emissions and according to The United Nations Environment Programme, the construction industry has led to 38% of all global carbon emissions (1). Since most of the modular construction is done in a factory, there are fewer workers on the actual construction site so traffic and heavy machinery are not contributing to as much air pollution in the on-site area (2). One study estimated a reduction of 30% in total greenhouse gas emissions from modular construction compared to traditional construction (3).
Energy Efficiency
With the controlled factory environment, modular buildings can have better insulation and sealing creating a more energy-efficient structure (1). Modular building can reduce total energy use during construction as well as the amount of energy the building uses after construction (3). The National Renewable Energy Laboratory has written about the potential for modular buildings to contribute to energy efficiency and decarbonization efforts nationally (4).
Overall, modular construction allows for more potential for the incorporation of sustainable practices, energy-efficient systems, recycling, and other innovative environmental building practices (8). While modular building is not the only solution to reduce waste and emissions and the construction sector, it is one way to help Truckee and California reach their climate goals.
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