Environmental experts tell us that residential construction is a significant contributor to environmental degradation due to the extensive use of resources and the generation of construction waste. According to a report compiled by the Synergy Foundation, 4 million tons of construction, renovation and demolition waste are generated annually in Canada.
The construction industry is coming under pressure from customers, local government and the workforce to build and operate with a lower environmental impact. The good news is that construction in Canada is transforming sustainable and responsible building practices, as we all become more conscious of the industry’s environmental impact.
In this article we’ll explore some of the energy-efficiency programs, waste management strategies and building practices already in place, and others gaining traction to reduce the waste produced by construction.
Designing for sustainability
The path towards waste reduction begins at the design stage. Your architect or designer plays a crucial role in integrating sustainable principles at the creative stages of the project. Thoughtful consideration should be given to incorporating energy-efficient design, using locally sourced materials, and optimizing the building’s orientation to maximize natural light and ventilation, with a strong emphasis on waste prevention.
The overall impact your construction project has on the environment can be significantly reduced from the outset by focusing on sustainable design principles. These may include efficient material use, lean construction methodologies and prefabrication as ways to minimize waste on the construction site.
Recycling and reuse of materials
Many construction materials can enjoy a second life if properly managed. Recycling and reusing building materials not only reduces waste but also conserves resources. Reclaimed wood, recycled steel, and salvaged bricks can be used again in new construction projects, minimizing the demand for new raw materials, while reducing the carbon footprint associated with extraction and manufacturing.
The construction of a 2,000 sq. ft. home in Canada will generate roughly 17,500 kg of waste. Waste diversion can reduce disposal costs by 30%, but most construction sites still use a single bin, sending over 90% of the waste generated directly to the landfill, instead of setting up a recycling station.
Prefabrication and modular construction
Prefabrication involves the assembly of building components off-site, to reduce construction time and environmental impact, and minimize on-site construction waste. Prefabrication allows for better control over materials, reduces the hands-on construction time, and can significantly decrease the overall waste generated during the building process.
Modular construction, a form of prefabrication, involves constructing entire sections off-site, delivering and then assembling them on-site. Modular components such as SIPs are manufactured with precision to fit together seamlessly. Construction times with panelized homes are greatly reduced over traditional building methods. SIP, or structurally insulated panel, buildings have a highly insulated material which is sandwiched between two durable plywood, fibreglass, or recycled wood/polymer panels. The on-site waste from the construction of a new SIP house is far less than with conventional stick buildings erected with traditional building materials.
Waste audits and management
Waste audits must be conducted during the construction process to help the builder understand the types and quantities of waste being generated. By identifying each source of waste, the builder can implement more effective waste reduction strategies, to divert as much material as possible from landfills.
An effective waste management plan involves sorting and separating materials at the construction site, and establishing designated areas for recyclables, reusable materials, and non-recyclable waste.
Lean construction practices
Lean construction practices are a respect- and relationship-oriented production management approach to home building, that aims to maximize value while minimizing waste. Key principles of lean construction include continuous improvement, waste removal, client satisfaction, focus on flow, generating value, and respect for people. This methodology targets the elimination or minimization of various types of waste, such as defects, overproduction, waiting, non-utilized talent, transportation, inventory, motion, and extra-processing.
Defects are avoided to eliminate rework and corrections due to errors or poor quality. There’s an emphasis on just-in-time delivery of materials to avoid excess stockpiling and waste, and the elimination of overproduction. Producing more than that is needed, or producing it earlier than required, typically results in waste or excess inventory, the result of accumulation of materials beyond what is immediately required.
Delays in the construction process due to resource unavailability or dependencies, or unwarranted movement of materials or equipment, can be costly. It’s also critical to leverage the full potential and creativity of the team. Unnecessary motion must be avoided because it results in unproductive workers due to excessive movement.
Integrating energy-efficient technologies into your construction process not only reduces energy consumption but also contributes to waste reduction. A sealed building envelope, superior insulation, energy-efficient windows and doors, advanced HVAC systems, and choosing durable materials, can decrease the need for frequent replacements or repairs. Through careful planning at the design phase, construction waste is minimized over the building’s entire lifespan. Energy-efficient construction practices encourage reusing and recycling of materials, which can reduce the need for new resource extraction and the associated energy consumption.
A responsible construction project involves considering water efficiency both during and after construction. Implementing strategies such as rainwater harvesting, efficient irrigation systems, and permeable surfaces can minimize water waste. Proper grading and drainage planning can prevent erosion and water damage, reducing the likelihood of repairs and material replacement after occupancy.
Implementing rainwater harvesting systems, using greywater recycling, and employing efficient irrigation techniques can conserve water, minimize water waste, prevent erosion, and reduce water damage. Collecting rainwater for later use should reduce your demand for city or municipal water sources.
Installing efficient irrigation systems, such as a drip system, can minimize water waste by delivering water directly to the base of the plants. Drip irrigation can reduce runoff and evaporation, and prevent soil erosion.
The use of permeable surfaces, such as permeable pavers or gravel, allows rainwater to infiltrate the soil, reducing runoff, while preventing erosion and minimizing water damage. Proper grading and drainage planning help direct water away from the house, preventing water damage and erosion over time, while promoting the efficient use of water in your landscaping.
Life cycle assessment (LCA)
Conducting a life cycle assessment is a way to evaluate the environmental impact of your building throughout its entire life, from the raw material extraction to its eventual demolition. By understanding the cradle-to-grave environmental impact of your home, your designer and builder can make informed decisions to minimize its overall footprint.
LCAs also provide valuable insights into the environmental costs associated with different materials, helping your builder choose more sustainable options. A life cycle assessment offers a systematic set of procedures for compiling and examining inputs and outputs of materials, transportation, storage, use, recovery, reuse, and disposal, providing a more complete picture of the total environmental impacts associated with the construction of your home.
Built Green® job site waste and sustainability
The Built Green® certification program is a holistic, sustainable building approach that offers you as a homeowner a healthier, more durable home with a reduced environmental impact. Built Green® recognizes that the construction industry is a significant contributor to waste generation and is a leader in sustainable building practices.
If you’ve ever driven by new homes and noticed huge trash bins full of excess building material? That waste is the result of inaccurate measurements, unused lumber and other building materials. Waste is prevented through greater efficiency, precision and accuracy, and these green principles can reduce material waste by 50% or more over traditional stick-building methods.
The Built Green® program trains builders to simplify the job site pre-sorting process, with meticulous hand sorting of construction waste to separate reusable materials from actual garbage. By emphasizing responsible waste handling the program aims to reduce the environmental impact construction activities have on the site, addressing waste materials on the construction site and encouraging recycling and repurposing of those materials
Higher levels of Built Green® certification also require the inclusion of salvaged or recycled content in at least ten of the materials used, further promoting the use of recycled materials in your home’s construction.
A green home is designed and built around low VOC products and materials that won’t off-gas chemicals into the air. They use engineered lumber that is bonded together with formaldehyde-free adhesive and low VOC-engineered hardwood flooring. Non-toxic materials must meet different thresholds of VOC emissions compliance, depending on the material. Using non-toxic materials in building assemblies and furnishings can also reduce the release of toxic chemicals into the environment after construction, should debris from your home ever find its way into the environment following a storm, flooding or high winds.
Built Green® promotes the use of durable materials that will have a lower environmental impact. Sustainably built homes won’t require substantial renovations every five to ten years, like many of the conventional homes. By including durability features like airtight building envelopes, continuous insulation, engineered lumber that resists warping, 30-year shingles, and waterproofed foundation walls you can enjoy a longer lifespan and significantly lower maintenance costs.
Educating and engaging stakeholders
Building sustainably requires the cooperation and understanding of all stakeholders, including certification program trainers, architects and builders or design-build contractors, trades, suppliers, and homeowners. Educating these stakeholders about the importance of waste reduction and sustainable building practices creates a collective awareness and commitment to responsible construction and sustainable building techniques.
As the global population continues to grow, with Canada’s population growth exceeding that of available housing units, the demand for new homes greatly exceeds demand. With all the new homes Canada desperately needs, it becomes even more important that we adopt waste-reduction strategies in home construction.
Through sustainable design, material recycling, efficient construction practices, and ongoing education, the construction industry has the opportunity to lead the charge to a more sustainable and responsible housing future.