Circularity in Construction

Circularity in the built environment aims to minimize waste and maximize the life of materials by keeping them in use, or circulating them, for as long as possible. The concept of a circular economy highlights the shift away from the current linear model of consumption, which follows the process of take-make-waste — where materials are extracted, produced, and then thrown out after initial use — and rather towards recirculating materials — where products are maintained, reused, repaired, or recycled. This approach helps to decrease the amount of waste generated, conserve resources, and reduce the environmental impact of production and consumption. 

The Ellen MacArthur Foundation has visualized the circular economy principles through their butterfly diagram depicted below. The right side of this diagram shown in blue, known as the technical side, is most relevant for contractors as it depicts products that are used rather than consumed. This diagram also illustrates a clear hierarchy with maintaining/prolonging use being the highest value, followed by reuse/redistribution, refurbishing/remanufacturing, and finally recycling.  

The construction industry has a unique opportunity to make a significant impact on the circular economy, given its high use of resources and amount of waste generated. According to 2018 EPA estimates, construction and demolition waste accounted for more than double the amount of municipal solid waste (i.e., household trash) in the United States. But as all contractors know, the construction world is centered around time and money. Therefore, when it comes to rethinking “waste” as a valuable resource, successful implementation of circular practices requires integrating these best practices into existing processes. The strategies explored below are categorized by construction phases and intended to be an introduction for potential best practices to incorporate circularity.

Preconstruction 

Preconstruction strategies should be considered as early as possible during the design phase to maximize efficacy, avoid budgetary surprises, and minimize rework. Therefore, delivery models where contractors are involved in the preconstruction phases are most likely to be successful in meeting circularity goals. Examples of strategies include:

1. Salvage assessment: For all projects involving demolition (full or partial), complete an assessment of the areas to be demolished and provide an inventory of salvageable materials to the design team for consideration in the new design. For materials not included in the new design, explore reuse markets, local donation centers, and manufacturer take-back (or extended producer responsibility) programs. 
2. Circularity pricing lens: During pricing phases, add a circularity lens to value engineering exercises. Although this may require considering trade-offs between value engineering and circularity, many times these approaches align. Some examples of considerations include:
   1. Ask subcontractors if there are ways to be more efficient from a material standpoint. Is there a lot of waste (and wasted time) from inefficient cuts that can be reduced with standard dimensions?
   2. Identify details where finishes could be deleted, providing a simpler finish schedule and reducing material demands.
   3. Identify opportunities to use materials from reuse markets, decreasing material cost and production while also supporting local small businesses. 
   4. Review the plans for any components that could be assembled offsite, reducing waste and maximizing labor efficiency onsite. For example, consider pricing panelized walls as an option. The additional material cost may be offset by decreased labor cost or overall schedule savings. 
   5. Identify opportunities that will improve chances of future disassembly. For example, use mechanically fastened systems ILO glues and adhesives when possible. 
3. Construction and demolition waste management plan: Develop a waste management plan early so that it can be coordinated with the job-site logistics plan and project schedule. Considerations for successful waste management include:
   1. Source separation drastically increases the reuse and recyclability potential of materials. Separate material types out into individual bins as much as possible. 
   2. Demolition can oftentimes generate a larger amount of waste than new construction. Complete a salvage assessment and carefully consider strategies to reduce demolition rubble taken to landfill, such as identifying materials that can be deconstructed and reclaimed or sent back to manufacturers through a take-back program. Ceiling tiles and carpeting are examples of products that may be part of these take-back programs.
   3. For new construction waste, identify how each type of material will be handled in the instance of waste generated or surplus material. Consider this in the context of the project schedule and logistics. (insert photo #2 here)
   4. Include the waste management plan or relevant sections as part of the pricing requests to subcontractors, ensuring everyone is set up for success and understands the expectations.
4. End of use plan: Ask the design team and/or owner about the project’s end of use plan. For example, are interior finishes expected to be updated every 7-10 years and if so, has disassembly been considered in the design? Understanding how the owner will use and update the space will help ensure those expectations are implemented in construction. 

Construction

Ideally, the bulk of circularity planning has been completed before this phase. The construction phase focuses instead on the tracking and implementation of those preconstruction plans. 

1. Construction and demolition waste management plan: Continuously track waste monthly and analyze progress towards the waste management goals. Use a spreadsheet to track hauling tickets for all materials leaving the site and identify which materials were diverted from landfill vs which materials were sent to landfill.
2. Procurement of materials: Ensure the correct materials coordinated in the preconstruction phase are purchased and installed. If availability issues arise, ensure alternative products meet circularity goals. Collect relevant product data, install instructions, material ingredient disclosures, etc.
3. End of use plan: Throughout the construction phase, track changes and/or add helpful redline notes to the drawings that would assist with future disassembly. 

Closeout

The closeout phase of a project includes turning the building over and submitting relevant documentation to the owner.

1. Construction and demolition waste management plan: Calculate the final project waste diverted from landfill as a percentage of the total waste generated and hauled offsite. Identify any challenges or reasons why the implementation may have varied from the waste management plan to track lessons learned. 
2. End of use plan: Ensure any tracking notes from #3 above are incorporated in the owner’s as-built drawing set. In the closeout packet, document installed products through approved submittals and include relevant backup documentation required for future materials that are eligible for manufacturer take-back programs.

In summary, adopting circular economy principles in construction practices can help to reduce waste, conserve resources, and promote sustainable building practices. It is important to consider this approach in the preconstruction phase, as it has the greatest potential to reduce the environmental impact of construction. In addition, implementing circularity best practices introduces other benefits such as increasing client services, supporting the local economy by circulating valuable materials, and promoting a more sustainable future.

Christine Davis works on LEED development at the U.S. Green Building Council. Her previous experience includes project management on a variety of commercial construction projects, including small renovations to high-rise new construction. The views expressed in this article are her own and independent of her work at USGBC.