5. Documentation Recommendations

One of the most impactful things that can be done to ensure that a building can be adapted for future uses is to document the as-built conditions (including shop drawings). Designers should work with the client to create a plan to ensure that drawings will be updated to reflect changes over time and will remain accessible regardless of turnover or sale of the property.

To ensure that structural components can be deconstructed and reused, it is important to understand material composition, sourcing, structural capacity, and past uses. Previously noted processes for identifying structural elements, such as material passports or physical stamping can be utilized to support this process. However, a universal method of labeling mass timber components has yet to be developed. Challenges that will need to be anticipated as solutions are generated are longevity of the label (will this label be legible 100+ years in the future?) and how to incorporate labeling into the manufacturing process in a cost-effective way.

One of the most common challenges faced in the field that can be difficult to predict is the use of “non-prescribed fasteners” (Sandin et al., 2022). These are typically nails that are installed in the field that are not indicated in the original drawing set. These nails are usually installed because they are perceived by the installer as necessary to keep an element in place connecting it or required to tighten a joint. These additional fasteners are difficult to detect and remove, can inhibit the deconstruction process and lead to damage of structural components. Furthermore, “non- prescribed fasteners” can pose a risk to the health and safety of workers during the deconstruction process. During a deconstruction case study at Villa Annenburg, existing trusses were connected with nails that were unknown to the disassembly team. As a crane attempted to lift the trusses, the team was not aware that the trusses were stuck, and the nails yielded suddenly (Sandin et al., 2022).

To avoid non-prescribed fasteners, it is important to include a note within the drawings set that these should be avoided. This message should be reiterated to the mass timber erection team. Additional measures that can be taken are to plan for more elements to be pre-assembled in a factory, where only planned fasteners are used (Sandin et al., 2022).

Conclusion

Beyond this simple list of recommendations, the single most effective thing we can do as designers to promote the reuse of existing building stock is to design beautiful, high quality, durable, well-functioning buildings that people come to love. In return, people will continue investing money and effort into maintaining and adapting these spaces over time.

Steel and concrete structures are robust and resilient enough to last hundreds of years. However, to survive these structures must also be inspiring and beautiful. A building needs to feel precious enough for people to want to maintain and reuse it. Too often, steel and concrete structures fail to capture the hearts of their users, eventually fall into disrepair, and are ultimately demolished.

Mass timber naturally lends itself to creating warm, inviting, beautiful spaces where people feel comfortable. Beyond this, wood is a material whose value can actually increase over time. Unlike other structural materials like concrete or steel, wood shows its age honestly. The older wood gets, the more it reflects its previous lives and experiences. With old wood comes a story that instills the material with character and a sense of authenticity. This is why salvage wood can be sold at a premium to virgin material.

It seems likely that this quality can be leveraged in salvaged mass timber elements as well. Imagine a flourishing mass timber market where “new” buildings are composed of mass timber structural components pulled from various deconstructed buildings -- embracing variations in color and finish, connection type, and wear -- all collaged together within a single structural system. Structural components from especially notable mass timber buildings may be in highest demand so that “newly” constructed buildings may boast that they own a piece of that previous history, retelling these stories within a lobby or gallery space. A column from a retired multifamily building where a child’s height was marked as they grew may be reused in a new single-family home because of its sentimental value.

This is the vision that designers must strive for as we advocate for design changes that account for the future adaptability of mass timber structures. There is much more work to be done to achieve this vision, including making EPDs an industrywide standard, the advancement of more customizable LCA tools, the development of dry, low embodied carbon assemblies that meet acoustic and fire requirements, additional research simulating the deconstruction process of mass timber components, and the promotion of circular economy through financial incentives, policy, and salvaged material databases.

The decisions we are making today will either facilitate or impede our ability to reuse, deconstruct, or recycle mass timber building components for hundreds of years in the future. As designers we should embrace this future-forward approach on every project and advocate for this level of foresight in every aspect of design.

References

Bergman, R. D., Falk, R. H., Gu, H., Napier, T. R., & Meil, J. (2013). Life-cycle energy and GHG emissions for new and recovered softwood framing lumber and hardwood flooring considering end-of-life scenarios. Res. Pap. FPL-RP-672. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 35 p.

Brandao, M. Levasseur, A. Kirschbaum, M. U. F., Weidema, B. P., Cowie, A. L., Jorgensen, S. V., Hauschild, M. Z., Pennington, D. W., & Chomkhamsri, K. (2013). Key issues and options in accounting for carbon sequestration and temporary storage in life cycle assessment and carbon footprinting. International Journal of Life Cycle Assessment, 18, 230-240. https://doi.org/10.1007/s11367012-0451-6

Building D(emountable) / architectenbureau cepezed. (2020). ArchDaily. https://www.archdaily.com/936389/ building-d-emountable-architectenbureau-cepezed

Building a world free from waste and pollution. (2021). Ellen MacArthur Foundation. Retrieved March 27, 2023, from https://ellenmacarthurfoundation.org/articles/ building-a-world-free-from-waste-and-pollution

Churkina, G., Organschi, A., Reyer, C. P. O., Ruff, A., Vinke, K., Liu, Z., Reck, B. K., Graedel, T. E., & Schellnhuber, H. J. (2020). Buildings as a global carbon sink. Nature Sustainability, 3(4), 269–276. https://doi.org/10.1038/ s41893-019-0462-4

Circle Economy. (2022). The Circularity Gap Report 2022 (pp. 1-64, Rep.). Amsterdam: Circle Economy.

Creasman, P.P. (2013). Ship Timber and the Reuse of Wood in Ancient Egypt. Journal of Egyptian History, 6, 152-176.

Cristescu, C., Honfi, D., Sandberg, K., Sandin, Y., Shotton, E., Walsh, S., Cramer, M., Ridley-Ellis, D., Risse, M., Ivanica, R., Harte, A., UiChulain, C., De Arana-Fernandez, M., Llana, D. F., Iniguez-Gonzalez, G., Garcia Barbero, M., Nasiri, B., Hughes, M., & Krofl, Z. (2020). InFutURe Wood Report 1: Design for deconstruction and reuse of timber structures – state of the art review. ForestValue.

Elcock, D. (2007). Life-cycle Thinking for the Oil and Gas Exploration. Argonne National Laboratory. https://www.evs. anl.gov/plublications/doc/LCA_final_report.pdf

EPA. (1998). Extended Product Responsibility: A Strategic Framework for Sustainable Products. EPA530-K-98-004. Solid Waste and emergency Response (5306W). https:// archive.epa.gov/wastes/conserve/tools/stewardship/web/ pdf/eprbrochure.pdf

Hawkins, W. (2021). Timber and carbon sequestration. Structural Engineer. 99. 18. https://doi.org/10.56330/ ALFK4016

Heinrich, M., & Lang, W. (2019). Materials Passports – Best Practice. Innovative Solutions for a Transition to a Circular Economy in the Built Environment. Technische Universitat Munchen, in association with Buildings As Material Banks (BAMB).

Höglmeier, K., Weber-Blaschke, G., & Richter, K. (2013). Potentials for cascading of recovered wood from building deconstruction—A case study for south-east Germany, Resources, Conservation and Recycling. 78, 81-91. https:// doi.org/10.1016/j.resconrec.2013.07.004.

Hoxha, E., Passer, A., Saade, M. R. M., Trigaux, D., Shuttleworth, A., Pittau, F., Allacker, K., & Habert, G. (2020). Biogenic carbon in buildings: a critical overview of LCA methods. Buildings and Cities, 1(1), pp. 504-524. https:// doi.org/10.5334/bc.46

Hradil, P., Asko, T., Wahlström, M., Huuhka, S., Lahdensivu, J., & Pikkuvirta, J. (2014). Re-use of structural elements; Environmentally efficient recovery of building components. 10.13140/2.1.1771.9363.

IPCC, Summary for Policymakers. Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press, 2014.

International Organization for Standardization. (2017). Sustainability in buildings and civil engineering works – Core rules for environmental product declarations of construction products and services (ISO 21930:2017).

Lehman, E. (2018). October 15, 1934: Glued Laminated Timber Comes to America. Forest History Society. https:// foresthistory.org/october-15-1934-glued-laminatedtimber-comes-to-america/

Leonard, A.G.K. (2008). Josiah George Poole (18181897): Architect and Surveyor serving Southampton. Journal of the Southampton Local History Forum, 13-27. https://southamptonlocalhistorycentre.files.wordpress. com/2014/11/lhf-journal-13-spring-2008.pdf

Lewis, M., Huang, M., Carlisle, S., & Simonen, K. (2023). AIA-CLF Embodied Carbon Toolkit for Architects. Part I. Introduction to Embodied Carbon. Carbon Leadership Forum.

Libby, B. (December 2022). The PAE Living Building Rises in Portland, Oregon. Metropolis Magazine. https:// metropolismag.com/projects/the-pae-living-buildingportland/

Lippke, B., Puettmann, M., Oneil, E., & Dearing Oliver, C. (2021). The Plant a Trillion Trees Campaign to Reduce Global Warming – Fleshing Out the Concept. Journal of Sustainable Forestry, 40(1), 1–31. https://doi.org/10.1080/1 0549811.2021.1894951

Long-Term Biogenic Carbon Storage. (n.d.). WoodWorks | Wood Products Council. Retrieved March 28, 2023, from https://www.woodworks.org/resources/long-termbiogenic-carbon-storage/

Love, S. (2007). Extended producer responsibility of treated timber waste. Paper presented to Sustainable Building Conference (SB07), Auckland, 14-16 November.

Moody, R. C. & Hernandez, R. (1997). Chapter 1: GluedLaminated Timber. Engineered wood products - A guide for specifiers, designers, and users. USDA Forest Service, Forest Products Laboratory. Chapter 1. p.1-1 - 1-39.

Nunes, Andey & Palmeri, Jordan & Love, Simon. (2019). Deconstruction vs. Demolition: An evaluation of carbon and energy impacts from deconstructed homes in the City of Portland Submitted to: City of Portland Bureau of Planning and Sustainability (BPS).

O’Connor, J. (2004). Survey on actual service lives for North American buildings. Forintek Canada Corporation.

Our Endangered World. (2023). Is Epoxy Resin Bad for the Environment? https://www.ourendangeredworld.com/eco/ is-epoxy-resin-bad-for-the-environment/

Haddadi, R., & Rinke, M. (2020). Early glulam for temporary large scale structures in Switzerland. Iron, Steel and Buildings: Studies in the History of Construction. The Proceedings of the Seventh Annual Conferences of the Construction History Society. 477-488. University of Antwerp. https://hdl.handle. net/10067/1731640151162165141

How to Include Biogenic Carbon in an LCA. (n.d.). WoodWorks | Wood Products Council. Retrieved March 28, 2023, from https://www.woodworks.org/resources/how-toinclude-biogenic-carbon-in-an-lca/

Nicklin, A. & Falk, B. (2020). Reclaiming the Future: What’s New in Used Wood. Docslib. Retrieved March 28, 2023, from https://docslib.org/doc/10857866/reclaiming-thefuture-whats-new-in-used-wood

Rammer, D. R. & Moura, J. (2013). Structural evaluation of the second oldest glued-laminated structure in the United States. In: Gen. Tech. Rept. FPL-GTR-226. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 269-276.

Rypkema, D., Grosicki, B., Swink, R., Cotton, K., Frystak, A., Bruni, C., & Herr-Cardillo, S. (2021). Treasure in the Walls – Reclaiming Value Through Material Reuse in San Antonio. PlaceEconomics.

Saleh Pascha, K. (2014). Developments in timber construction materials. Emergent Timber Technologies Materials, Structures, Engineering, Projects. 36-57. 10.1515/9783038216162.

Sandin, Y., Shotton, E., Cramer, M., Sandberg, K., Walsh, S. J., Östling, J., Cristescu, C., González-Alegre, V., Íñiguez-González, G., Llana, D. F., Carlsson, A., Ui Chulain, Caitriona, Jackson, N., Barbero, M., & Mejía, A. (2022). Design of Timber Buildings for Deconstruction and Reuse — Three methods and five case studies (open access).

Spartz, J. T. (2014). Historic Glued-Laminated Arches Evaluated for Structural Quality Lab Notes. https://www. fpl.fs.usda.gov/labnotes/?p=2593

The Carbon Leadership Forum. (2019). Life Cycle Assessment of Buildings: A Practice Guide. Version 1.1. http://hdl.handle.net/1773/41885

The Circularity Gap Report. (2022). Circle Economy. https://drive.google.com/file/d/1NMAUtZcoSLwmHt_ r5TLWwB28QJDghi6Q/view?usp=embed_facebook

The Delphi Group. (2021). Circular Economy & The Built Environment Sector in Canada. Final Report.

Toth, Z., Volt, J., & Jankovic, I. (2021). A Paris-Proof Retail Real Estate Sector. Taking Stock of Regulatory and Market Developments. Buildings Performance Institute Europe (BPIE).

Unit Structures, Inc. (n.d.). Retrieved March 28, 2023, from https://www.facebook.com/people/Unit-StructuresInc/100063746191371/

When to Include Biogenic Carbon in an LCA. (n.d.). WoodWorks | Wood Products Council. Retrieved March 28, 2023, from https://www.woodworks.org/resources/whento-include-biogenic-carbon-in-an-lca/

Wood, S. (n.d.). Deconstruction Program – City of Portland, Oregon. Bureau of Planning and Sustainability. Webinar Presentation.

Wood Innovation and Design Centre. (2015, November 9). Architect Magazine. https://www.architectmagazine.com/ project-gallery/wood-innovation-and-design-centre_o Woodworks Innovation Network. (n.d.). PAE Living Building. Retrieved March 29, 2023, from https://www. woodworksinnovationnetwork.org/projects/pae-livingbuilding

WWF Webinar on Bioenergy Carbon Footprint Tool. (2021). Webinar. World Wildlife Fund. Retrieved March 28, 2023, from https://www.worldwildlife.org/videos/wwf-webinaron-bioenergy-carbon-footprint-tool

ZGF. (2001). Measuring Lifecycle Impacts of Wood With New Sustainable LCA Tool Retrieved March 28, 2023, from https://www.zgf.com/ideas/3356-new-tool-helpsdesigners-measure-lifecycle-impacts-of-wood

Acknowledgments

Thank you to:

Alexis Feitel, PE

Structural Engineer + Team Carbon Unit Director

KL&A Engineers & Builders

Kate Sector, LEED GA, LFA, WELL AP

Design Performance Manager

Lake|Flato Architects

Ryan Yaden, AIA, LEED AP BD+C Associate Partner

Lake|Flato Architects who shared their time and expertise by serving as reviewers for this paper.