In Support of Mass Timber: Strategies for Reducing Risk
Why do developers, owners, and AEC industry professionals choose not to use mass timber for new projects? This is the question at the core of a study I completed as part of the SmithGroup Exploration Grant program. The premise is that knowing this information will allow industry professionals to better support the development of new mass timber projects. To effectively promote the use of mass timber we need to know the potential roadblocks and how to address them with our clients. This study identifies five core risks and strategies to address them.
Seven representative industry leaders were surveyed to provide their thoughts and experience about recent projects that considered using mass timber at the early stages of development, and then did not utilize it. They have provided insight into why they initially considered mass timber, why they did not use it, and what they perceive to be the obstacles to using mass timber on future projects.
Five primary categories of obstacles, or risks, were identified to future mass timber projects. These risks are:
- Costs & supply chain unpredictability
- The lack of market and performance data
- The lack of design and construction team experience
- The unknowns of approvals and permitting
- The lack of standardization for seismic/lateral structural performance
The primary takeaway from this study is that in order successfully foster the use of mass timber we must support our clients by reducing their risks of adopting this system. Here are some basic steps that can be taken to address each area of risk. In a general, the strategy is to be prepared to address these risks head on and have as much information as possible to provide to your client. Suggestions for how to do this are as follows:
Cost and Supply Chain
System costs and supply are a main concern, and variable across regions, so you will need to develop and maintain local information about these issues in your area. Local projects can be identified and used for current data regarding cost, suppliers, etc. If no local projects are available, the next option could be to expand your search to a wider area or contact some of the larger suppliers about what they know about your region. Be prepared to give your client as much information about your local market as possible.
Metrics for mass timber come more into focus with each new project. Groups like WoodWorks and Think Wood have some of the most current information. Regional suppliers are also good options for having local data and should be able to identify local project examples and local project teams. It may also be possible to find peers and members of previous project teams who have information and experience on mass timber projects. The mass timber community is a cooperative and informed resource.
Team experience is one of the biggest issues. Specific team members identified as risks were general contractors and structural engineers. If you are paired with either of these partners and they are not willing to take on the challenge they will most likely be a liability to the success of your project. Because of this, the strategy is to form your mass timber team early. You can then be confident that your team will be interested and able to take on a project with the best chance for success. Because mass timber is prefabricated, any distribution of elements such as pipes, conduits, or ducts must be thoroughly laid out and detailed prior to fabrication. Not only do your MEP teams need to have provided completed designs, but your fire sprinkler engineer, A/V, and any other discipline that would have any kind of penetration or impact on the structure will also need to have completed designs much earlier than would be required on a steel or concrete structure.
Approvals and Permitting
Because local jurisdictions all have their own approaches to permitting, they will likely have their own approaches to mass timber. These agencies’ familiarity with mass timber in the building and fire codes will determine their ability to review and approve a mass timber project. A preparatory meeting with your local building and fire department is a recommended course of action to identify any specific questions they may have. The more information that you can bring early to your client about the local approvals process, the better equipped they will be to set expectations.
The issue of seismic/lateral system performance of mass timber is important enough to separate out from project approvals. Mass timber is not yet included in the International Building Code as a prescriptive lateral system. If your intention to use mass timber elements in this way, the only path available for using it is through an Alternative Means and Methods Request (AMMR) process, which can be lengthy and expensive. More than likely a hybrid system will be required, which means introducing steel or concrete into the system to account for lateral forces. This will translate into needing to be prepared to factor in the added complexities of how this will work. Examples of this are the added cost of the steel or concrete, extra time for coordination, different construction tolerances for the different systems, and understanding the impact to construction sequencing and timelines. Some initial study into how these complexities have been handled on different projects can provide insight into how this can be done effectively.
These are only a few ideas about how to address some of these issues. The key strategy is to be prepared to address these issues when they arise. Being prepared to reduce the risk exposure of your client if they use mass timber is only part of the equation for a successful mass timber project. There are still many unknowns. If we as architects push too hard on projects to use mass timber and they fail, we may see more lasting impact by pushing back the adoption of mass timber in mainstream construction projects. By listening to and supporting our clients when mass timber makes sense is the way we will make mass timber succeed.