Let’s talk trash, or rather construction waste. According to the EPA, US construction waste has increased from 170,000 tons in 2005 to over 600,000 tons in 2018. This waste consists of concrete, wood, drywall, steel, bricks and clay tile, asphalt shingles, and asphalt concrete. It includes new construction, renovation, and demolition of residential construction, commercial construction, roads, and bridges.
What can we as owners, architects, engineers, and contractors do to turn this 1.2 quadrillion pound ship around? There are many ways to reduce construction waste. This BX article from 2020 lists several ways to help reduce construction waste. Since planning recycling efforts, working with like-minded waste-reducing subcontractors, deconstructing, and organizing your inventory to prevent duplication have been covered, I’d like to cover another method of reducing construction waste. Offsite construction, also known as prefabrication, has also been shown to reduce construction waste, increase sustainability, decrease build time, make efficient use of existing labor, and improve schedule accuracy and cost estimates.
What does offsite construction include?
Offsite construction can mean anything from a tiny home, ADU (Accessory Dwelling unit aka granny pads), containers, precast concrete, component manufacturing including roofs, walls, and floors, to modular for single-family homes, multifamily units, apartments, hotels, and other commercial structures. Marriot, McDonald’s, and Aldi are among the companies that regularly use offsite construction methods to decrease waste, schedule, and labor requirements. Marriott currently has over 50 hotels built using various forms of offsite construction. Jennifer Abuzeid, Senior Director–Global Design Strategies, mentions that the “great benefits of modular include consistent product quality, eliminating change orders, and reducing punch lists and job site waste.”
86% of architects and engineers surveyed believe prefabrication / offsite construction reduces construction waste and 85% of GCs and CMs believe waste is reduced when prefabrication is used for construction. 41 million tons of construction debris is wood and 15 million tons is drywall and plaster. Much of this is new material. High yield cutting equipment is standard in many offsite production facilities meaning there is less new material waste. In addition to keeping this debris out of the landfill, we are saving the resources required to overproduce the material that ended up in the dumpster. With offsite construction, they have the ability to reuse partial packages of material on the next unit in line and there is less onsite damage or theft since the prefabrication occurs indoors in a protected environment.
Daniel Simons, principal at DBA cites reduced construction waste as the main factor on the LEED Platinum certification on their first modular build, Union City Flats multifamily project in Union City, California. Even when the packaging material is used to get modular units on-site the waste is reduced between 22-40% according to 2 Modular Building Institute research projects. This can be seen in the waste management area of offsite construction sites as they are being installed, the dumpster and removal schedule is greatly minimized.
Additional Benefits of Offsite Construction
In addition to the reduction in construction waste, offsite construction provides other sustainability benefits in the reduction of the carbon footprint of the building process. Through fewer materials being used, to more efficient material transportation, decrease in labor transportation, and the reduction of materials required based on higher material yield. This all leads to more sustainable building practices everyone can benefit from.
Moving forward there are many options to reducing construction waste whether working on-site or offsite planning can go a long way. Using BIM and other software to accurately estimate the number of materials needed. Securing the material onsite from the elements and maximizing the yield or reuse of those materials and even incenting subcontractors with waste goals can help reduce our overall contributions to landfills. Offsite it is a matter of continuing to invest in systems that maximize material yields and choosing materials with increased durability to extend the life of our structures. So let’s keep talking trash and challenge ourselves on how each of us can impact turning this 1.2 quadrillion pound ship around.
This article was originally featured in The Source.