End-of-life and Beyond Building Life: Carbon Benefits of a Novel Mass Timber Wood Floor System, Evaluating End-of-Life Strategies, Recovery Rates, and Circular Design Implications

End-of-life and Beyond Building Life: Carbon Benefits of a Novel Mass Timber Wood Floor System, Evaluating End-of-Life Strategies, Recovery Rates, and Circular Design Implications | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article End-of-life and Beyond Building Life: Carbon Benefits of a Novel Mass Timber Wood Floor System, Evaluating End-of-Life Strategies, Recovery Rates, and Circular Design Implications Muzan Williams Ijeoma, Sovanroth Ou, Amin Nabati, Hao Chen, Michael Stoner, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7724324/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose Mass timber construction is gaining attention as a low-carbon alternative to conventional building systems, but the end-of-life (EOL) stage remains one of the least consistently modeled phases in building life cycle assessments (LCAs). This study evaluates how recovery pathways and connection strategies influence the climate performance of prefabricated hollow timber floor systems. Methods A process-based estimation approach was used to quantify the carbon footprint of two timber floor systems—Adhesive & Screw and Sharp Plate & Screw—following ISO 14040/44 standards. Four realistic EOL pathways (landfilling, downcycling, component reuse, and full assembly reuse) were assessed under three recovery-rate scenarios (90%, 60%, and 30%) to capture both ideal deconstruction and conventional demolition conditions. Cradle-to-gate impacts, biogenic carbon flows, and Stage D benefits were integrated to determine climate outcomes. Results Results show that reuse, particularly modular assembly salvage, delivers the highest climate benefit, achieving net-negative emissions and offsetting cradle-to-gate greenhouse gas impacts. Mechanical fastening systems (sharp plate and screw design) outperformed adhesive-based designs in both reuse effectiveness and environmental impact compensation (Stage D), emphasizing the importance of disassembly-friendly connections. However, downcycling benefits diminish sharply below 60% recovery, highlighting critical thresholds for climate performance. Furthermore, break-even recovery thresholds were identified: downcycling becomes environmentally favorable only when recovery exceeds 59%. In contrast, component reuse is beneficial from 15% recovery, and assembly reuse from as low as 10%. These thresholds reinforce the strategic advantage of designing for reuse, not just recycling. Conclusions The findings highlight the strategic advantage of designing for reuse rather than recycling, with disassembly-friendly connections and high recovery rates emerging as key enablers of climate-positive outcomes. This study provides new methodological and practical insights for incorporating EOL pathways into timber building LCAs and supports circular economy strategies in construction. Environmental Engineering Mass Timber Construction End-of-Life Scenarios Greenhouse Gas Emissions Circular Economy Life Cycle Assessment CDW Recovery Rates Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7724324","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":521280558,"identity":"8464b1e8-998c-455e-ae42-230182c118aa","order_by":0,"name":"Muzan Williams 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4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMass timber construction is gaining attention as a low-carbon alternative to conventional building systems, but the end-of-life (EOL) stage remains one of the least consistently modeled phases in building life cycle assessments (LCAs). This study evaluates how recovery pathways and connection strategies influence the climate performance of prefabricated hollow timber floor systems.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA process-based estimation approach was used to quantify the carbon footprint of two timber floor systems—Adhesive \u0026amp; Screw and Sharp Plate \u0026amp; Screw—following ISO 14040/44 standards. Four realistic EOL pathways (landfilling, downcycling, component reuse, and full assembly reuse) were assessed under three recovery-rate scenarios (90%, 60%, and 30%) to capture both ideal deconstruction and conventional demolition conditions. Cradle-to-gate impacts, biogenic carbon flows, and Stage D benefits were integrated to determine climate outcomes.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eResults show that reuse, particularly modular assembly salvage, delivers the highest climate benefit, achieving net-negative emissions and offsetting cradle-to-gate greenhouse gas impacts. Mechanical fastening systems (sharp plate and screw design) outperformed adhesive-based designs in both reuse effectiveness and environmental impact compensation (Stage D), emphasizing the importance of disassembly-friendly connections. However, downcycling benefits diminish sharply below 60% recovery, highlighting critical thresholds for climate performance. Furthermore, break-even recovery thresholds were identified: downcycling becomes environmentally favorable only when recovery exceeds 59%. In contrast, component reuse is beneficial from 15% recovery, and assembly reuse from as low as 10%. These thresholds reinforce the strategic advantage of designing for reuse, not just recycling.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe findings highlight the strategic advantage of designing for reuse rather than recycling, with disassembly-friendly connections and high recovery rates emerging as key enablers of climate-positive outcomes. This study provides new methodological and practical insights for incorporating EOL pathways into timber building LCAs and supports circular economy strategies in construction.\u003c/p\u003e","manuscriptTitle":"End-of-life and Beyond Building Life: Carbon Benefits of a Novel Mass Timber Wood Floor System, Evaluating End-of-Life Strategies, Recovery Rates, and Circular Design Implications","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-09-29 08:52:56","doi":"10.21203/rs.3.rs-7724324/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"baeef8b2-ea14-47ce-83fb-274be4881b44","owner":[],"postedDate":"September 29th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":55415811,"name":"Environmental Engineering"}],"tags":[],"updatedAt":"2025-09-29T08:52:56+00:00","versionOfRecord":[],"versionCreatedAt":"2025-09-29 08:52:56","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7724324","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7724324","identity":"rs-7724324","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}