Construction productivity in the United States has been stagnant for decades, falling well behind other sectors of the economy. Though multifamily construction productivity has been a lone bright spot in the construction industry, it hasn’t improved enough to lift the sector as a whole. Those studying the construction industry have widely noted this issue, and a recent New York Times op-ed by Ezra Klein reignited the discussion. The effects of this slowdown are tangible, as people struggle to find homes amid housing shortages and price increases. So, what is the solution? Part of the answer may lie in mass timber construction using panelized and modular construction methods.
Benefits of mass timber construction
Mass timber construction involves using engineered wood products to build structures. It is a sustainable, renewable, cost-effective alternative to traditional building materials like steel and concrete. The most popular engineered wood products used in mass timber construction include cross-laminated timber (CLT) and glued laminated timber (glulam), which both layer wood to increase the strength of a larger element. These products have strength-to-weight ratios comparable to other building materials, making them ideal for constructing tall buildings. Mass timber construction is also more sustainable than traditional construction methods, as it requires less energy, produces fewer emissions, and functions as a carbon sequestration method.
Fire safety is understandably top of mind when considering buildings constructed of mass timber. Engineered wood products are specifically designed to mitigate fire risk by forming a charred outer layer that protects the inner structure from damage.This engineering and active fire suppression systems often required in multifamily construction make it far safer than the raw lumber typically used to construct single-family homes.
How mass timber can improve construction productivity rates
Where mass timber really shines is in its potential to improve construction productivity.
Mass timber construction is a capital-intensive process, with much of the work being done on the front end, and everything, down to the last screw, is pre-planned. The lamination and millwork are then done at offsite factories and shipped to the final destination ready for assembly. This offsite prefabrication in controlled factory environments means that this construction method captures some of the “productivity magic” of assembly-line mass production.
Once at the worksite, mass timber components are assembled by workers like a large Lego set, with each piece secured in a predetermined location. Since there is no need to wait for concrete to cure, installing systems like plumbing, electrical, and climate control can begin almost immediately on finished floors.
These factors substantially increase the speed at which a building is constructed, with studies finding mass timber is over 25% faster than traditional methods. Though the process for each building is more customized and less scaled than the famed “Sears kit house” factories of the 20th century–where identical modular pre-planned panels were assembled in factories and replicated at scale–the approach enables partial modularization and factory-scalable assembly of some building components.
For labor, there is a vast improvement in the quality of work. Craig Triplett of the Chicago Regional Council of Carpenters said “studies have shown that it [mass timber] does create a better work environment and more productivity, [and] less stress.” Others have said that mass timber construction can lead to cleaner and safer construction sites.
Along the same lines, using prefabrication also means fewer negative impacts for neighbors near construction sites, from noise reduction and less dust generated by traditional construction methods that require more heavy work on-site.
While mass timber construction is gaining popularity in the United States, cities and states must update their building codes to really tap into its productivity potential.
In 2015, The International Code Council (ICC) published changes to the International Building Code (IBC), allowing mass timber construction up to six stories. In the 2021 IBC update, the ICC issued changes allowing mass timber buildings to be built up to 18 stories. Even if cities and states want to adopt only some aspects of the sometimes flawed model IBC, they should work to incorporate its suggestions on mass timber into their local codes.
Ten states have fully adopted the 2021 IBC recommendations on timber, while nine more have adopted some tall mass timber allowance. Cities like Denver, Dallas, and Austin also recently began to allow mass timber construction to reach greater heights. In Denver, this change has led to the development of the city’s tallest mass timber building. As more states and localities allow mass timber, production demand will grow, experience with the technique will increase, and economies of scale will make the industry an even more viable alternative for builders.
At the federal level, lowering tariffs on mass timber products and lumber may be worthwhile. There’s a substantial amount of capacity for engineered wood overseas and in Canada, where larger markets and greater experience working with the material has allowed the industry to scale up–meaning, it is often cheaper to import the product. While the three percent tariff on mass timber is responsible for some moderate price increases, the more significant barrier is our nine percent tariff on raw lumber that is subject to large fluctuations. These tariffs raise construction costs for wood-framed single family homes and deprive would-be mass timber manufacturers of the materials they would rely on to supply domestic construction projects. This barrier could ultimately slow the expansion of mass timber manufacturing facilities.
These barriers may seem modest, but these taxes can matter on the margin for large projects, and may cause developers to resist adopting a productive and sustainable construction method.
How mass timber can help usher in a new era of productive and sustainable construction
Mass timber construction is an innovative and sustainable building solution that can safely improve construction productivity while reducing environmental impact. Policymakers can advocate adopting this technique, leading to cleaner, safer, and more efficient construction practices. Expanded adoption of mass timber construction will create a positive feedback loop as more efficient methods and lower construction costs induce more projects into the development pipeline. Growing this would, in turn, help domestic mass timber manufacturers increase scale and better compete with traditional construction methods.
Allowing mass timber is not the be-all end-all of improving construction productivity rates, as many other restrictions slow construction and increase costs. However, increasing opportunities for the deployment of mass timber construction can be a critical part of the solution to our construction productivity woes and sustainable building needs.