Thornton Tomasetti Here’s How

This season finale steps back from a single technical challenge to examine how mass timber fits into the broader climate action landscape. Senior Principal Paul Becker and Vice President Kristina Rogers speak with Corporate Responsibility Officer Amy Hattan about how built-environment climate strategy must address both carbon reduction and resilience. The conversation connects several recurring themes from the season, including cost, procurement, permitting, insurance, supplier coordination, and project delivery. Rather than presenting mass timber as a universal solution, the episode emphasizes using timber where it makes the most sense and using hybrid systems to expand timber’s applicability. Sourcing considerations, including forest management and transportation, play an important role in deciding when mass timber is the right choice. The episode also explores more nuanced sustainability questions, including biogenic carbon, circularity, building-end-of-life planning, and design for deconstruction. The discussion positions mass timber as a powerful climate action tool when paired with responsible sourcing, efficient structural design, resilient planning, and strategies that help building owners meet long-term emissions goals. Key Insights Mass timber is part of a broader climate action toolkit. Timber can support embodied carbon reduction, but it should be evaluated alongside design strategy, resilience, power supply, and other decarbonization measures. Embodied carbon and operational carbon both matter. Low-carbon design requires attention to the materials used to construct a building and the energy used to operate it over time. Responsible sourcing is essential to mass timber’s climate value. Forest management, certification, transportation and manufacturing all affect whether timber delivers meaningful carbon benefits. Biogenic carbon requires a life cycle perspective. The carbon stored in wood can remain out of the atmosphere when buildings are durable, adaptable, and designed to keep materials in use. Circularity strengthens the long-term case for timber. Bolted and screwed timber systems can support future disassembly, but toppings and overlays must be considered carefully. Hybrid structures can improve performance and efficiency. Mass timber does not need to be used everywhere to be effective. Combining timber with other materials can help address fire, seismic, vibration, and cost requirements. Mass timber construction comes with additional co-benefits. Mass timber can reduce embodied carbon while also supporting local economies and providing biophilic benefits for building occupants. Topics Covered How mass timber fits into broader climate action and decarbonization goals Why embodied carbon, operational carbon and biogenic carbon should be considered together How sourcing, transportation and forest management influence timber’s sustainability value How hybrid structures can support performance, cost and climate goals Why circularity and design for deconstruction are important for timber buildings How mass timber can support owner climate targets, resilience strategies and biophilic design goals

This episode introduces GreenBox®, a prefabricated mass timber cassette system that reimagines how timber floors are manufactured, installed, maintained, and reused. Paul Becker and Kristina Rogers hear from Harry Crofton, who explains how cassette construction shifts work from the jobsite to the factory, where components can be built with tighter tolerances, greater quality control, and without exposure to weather or site constraints. The result is a system that can cover longer spans and be lifted into place quickly to speed construction. The discussion compares GreenBox with conventional CLT floor systems, focusing on how its plywood skins, glulam joists and specialized fill work together to optimize structural capacity, services integration and coordination, acoustics, and vibration control. Also discussed are the system’s fire performance and superior moisture-management detailing. Rather than solving each performance issue with added layers, GreenBox integrates multiple functions into one lighter, more efficient assembly. The episode also covers the benefits of GreenBox over the full life of a building and beyond: simple to repair, replace, and modify, it can also be easily disassembled and reused in circular construction. Key Insights GreenBox® is designed as an integrated mass timber floor system. Rather than treating structure, acoustics, vibration, and sustainability as separate design challenges, GreenBox combines these functions into one prefabricated cassette assembly. Prefabrication improves quality, speed, and consistency. By moving more work into a factory setting, GreenBox components can be built with tighter tolerances and then installed more efficiently on site.   The system offers a potential alternative to conventional CLT floors. GreenBox uses glulam joists and oriented strand board (OSB) to create I-sections, allowing long spans with much lower volumes of timber than would be required with a solid wood panel. Acoustic and vibration performance are central to the system. The specialized filling helps address two common challenges in timber floor design: sound transfer and footfall-based vibration. Moisture management is integral to the design. GreenBox uses a two-line moisture-defense strategy, with sealed upper joints to limit water entry and breathable lower joints that allow any moisture to escape. Performance validated through testing. Because the new system pushes beyond routine assumptions, fire performance was validated through physical testing. Circularity is a long-term value proposition. GreenBox is designed to be lifted into place, removed, reused or modified over time, supporting a more adaptable kit of parts approach to building design. Topics Covered How GreenBox® works as a prefabricated mass timber floor system How timber cassette systems can improve construction speed and consistency How GreenBox compares with conventional CLT floor assemblies How GreenBox floors can work well for big bays and long spans in large commercial and residential buildings Why acoustics and vibration matter in mass timber floor design How integrated systems can reduce material use and embodied carbon How acoustic and vibration performance, moisture control and services coordination affect adoption Why reusable structural systems are important for circular construction Thornton Tomasetti has partnered with National Timber Systems to produce GreenBox in the UK

In this episode, Senior Principal Paul Becker and Vice President Kristina Rogers talk with Associate Sami Rahman about vibration and acoustic performance in mass timber buildings. They discuss why mass timber floors behave differently from steel or concrete systems, suggest effective design strategies, and explain how modeling and field testing are helping us fine-tune performance so mass timber can be used in spaces with strict vibration criteria. Episode Overview: Vibration and acoustic performance are among the most technically challenging aspects of mass timber design. In this episode, Paul Becker and Kristina Rogers speak with Associate Sami Rahman about the relationship between vibration and acoustics in mass timber versus steel and concrete systems and what that means for design teams. The conversation examines how mass timber’s lighter weight makes floor vibration performance more complex. Strategies that improve vibration performance, such as creating composite action between CLT and concrete topping, can negatively affect acoustic separation. Using the Bowers College of Computing and Information Science at Cornell University as an example, Sami explains how to strike the correct balance for optimal performance. They also look at why involving acoustics and vibration experts early in the design process can provide better, more efficient outcomes. The discussion also explores options for successfully using mass timber in laboratories, research centers, and other spaces with sensitive equipment, such as manufacturing facilities. Sami discusses how advances in structural dynamics, finite element analysis (FEA), and validation of design models through field testing help us better understand and predict the behavior of mass timber structures. This will allow us to improve vibration-control design to allow mass timber to be used in more applications.   Key Insights Mass timber floors behave differently from steel or concrete. Because mass timber is relatively lightweight, vibration response is often governed by high-frequency impulse behavior rather than the low-frequency resonance commonly seen in heavier systems. Vibration and acoustics must be coordinated together. A design move that improves vibration performance can negatively affect acoustic performance, so both criteria need to be evaluated as part of the same design strategy. Modeling is stronger when calibrated with field data. Validating finite element analysis with heel-drop testing and impulse-response testing can help teams refine assumptions and better predict real-world mass timber performance. Vibration-sensitive buildings need early performance planning. Laboratories, research facilities, and other sensitive spaces require carefully considered framing strategies or localized enhancements to meet owner and equipment criteria. Early collaboration reduces late-stage redesign. For mass timber buildings, structural, acoustic, vibration, and architectural considerations should be integrated from the beginning rather than evaluated after the framing system is already set. Topics Covered Mass timber vibration design Acoustic performance in mass timber buildings High-frequency floor response CLT floor systems and concrete topping Composite action and acoustic separation Finite element modeling for vibration analysis Field testing and model calibration Laboratory vibration criteria Tuned mass dampers and active mass dampers Early coordination among structural, acoustic, and vibration teams

Engineers are still learning about how fire behaves in mass timber buildings, so codes – though evolving quickly – impose conservative limits on timber buildings. In this episode, Senior Principal Paul Becker and Vice President Kristina Rogers speak with Principal Ali Ashrafi about how fire risk is evaluated in mass timber buildings and how teams use performance-based fire engineering to design buildings that push beyond code-mandated size or occupancies – and how this process delivers safe mass timber structures and facilitates AHJ approvals. The conversation explores the variables that influence fire safety, such as building height, floor area, occupancy type, amount of exposed timber, site constraints on fire department access, and neighboring exposures. Ali explains why mass timber requires a project-specific approach that combines layers of safety and risk-reduction strategies, especially for taller buildings. Paul, Kristina, and Ali also discuss how forensic fire investigation; advanced modeling analysis; experimental research; and early conversations with owners, design teams, and AHJs can help build confidence in a mass timber fire strategy. The episode emphasizes robust design, clear communication, and informed decision-making as the mass timber industry continues to evolve. Key Insights: Mass timber fire safety is project-specific. Building height, occupancy and egress, amount of exposed timber, site access, and neighboring exposures all influence how fire risk should be evaluated. Exposed timber requires careful fire strategy. Many projects want to showcase the wood structure, but exposed timber can affect fire dynamics and may require additional analysis or design measures. Prescriptive codes are the starting point, not always the full solution. Mass timber code provisions continue to evolve, but innovative projects may need a more detailed fire-engineering approach. Performance-based fire design can support approvals. When a project pushes beyond standard code limits, performance-based analysis can help define safety objectives, test assumptions, and clearly communicate the design rationale to AHJs. Fire engineering benefits from real-world evidence. Forensic investigation, experimental research, and analytical modeling help teams understand how timber buildings may perform under different fire scenarios. Topics Covered Mass timber fire safety Performance-based fire design Exposed timber and fire dynamics Mass timber building code requirements Fire risk by height, occupancy, and building use Egress, suppression, and fire department access Authorities having jurisdiction (AHJs) and code approvals Forensic fire engineering and timber research Robust fire-safety strategies for innovative timber buildings

Mass timber procurement has a direct impact on structural design decisions, connection design, fabrication, and project delivery. In this episode, Senior Principal Paul Becker and Vice President Kristina Rogers discuss how supplier involvement in the SD (schematic design) phase, with or without a formal design-assist process, can help architects and structural engineers better align their designs for mass timber systems with available materials, fabrication methods, and erection sequences. The conversation focuses on why fabricator input is especially important in mass timber construction. Because products, species, connection preferences, and manufacturing processes vary by supplier, early coordination helps teams design to the material’s strengths, streamline coordination, minimize late changes, and improve constructability. Paul and Kristina also discuss options for connection design responsibilities and how that decision can impact design, fabrication and speed of erection. And they look at ways to adjust the design-bid-build delivery process – which doesn’t lend itself to design-assist – so it works more effectively for mass timber projects. Through examples including the Samuel H. Scripps Theater Center, the Roux Institute and Goldfinch Lofts, they explain how experienced teams collaborate to maintain flexibility, clarify performance expectations, and coordinate with suppliers to support successful delivery. Key Insights: Early supplier involvement can improve mass timber efficiency. Bringing a supplier or fabricator into the process early helps the design team align the structural system with available products, material dimensions, and fabrication preferences. Design assist helps reduce uncertainty. Fabricator input gives engineers and architects a clearer understanding of manufacturing capabilities, connection preferences and erection methods before key design decisions are locked in. Connection design requires close collaboration between engineers and fabricators, no matter who performs the scope. In mass timber buildings, connections can influence member sizing, load capacity, structural geometry and coordination with architectural intent. DFMA is central to successful mass timber delivery. Designing for manufacturing and assembly helps teams move from an abstract structural concept to a system that can be fabricated, shipped, and erected efficiently. Complex geometry benefits from fabricator collaboration. Curved glulam, long-span members and non-rectilinear systems often require early input on curvature limits, splice locations, connection options, and shipping size constraints. Traditional design-bid-build can work, but it needs adaptation. When early supplier selection is not possible, teams may need clearer performance criteria, more conservative assumptions, and additional coordination after the fabricator is selected. Better communication leads to better cost and constructability outcomes. The episode reinforces that mass timber projects benefit when engineers, timber fabricators, detailers, and erectors are part of the same technical conversation early enough to influence design. Topics Covered: Mass timber procurement strategies Design-assist for mass timber projects Early supplier/fabricator involvement Design-bid-build delivery for mass timber Mass timber connection design responsibilities Fabricator-led connection detailing Design for manufacturing and assembly, or DFMA Glulam roof geometry and curved timber systems Supplier selection Timber erection sequencing Constructability coordination Public, university and institutional procurement constraints Mass timber cost and schedule considerations

In this episode, hosts Paul Becker and Kristina Rogers take a deep dive with Jordan Komp into the design and delivery of Ascent, a landmark project that set a new precedent for tall mass timber construction. As the first building of its kind at this scale in the United States, the project required rethinking traditional approaches to structural design, code compliance and interdisciplinary coordination. The discussion highlights how Ascent has become a benchmark for future tall timber projects, influencing both industry practices and evolving building codes. The discussion focuses on how the properties of mass timber require designers to think and work differently than they do on steel and concrete structures. Greater elastic shortening, long-term creep and moisture-related movement demand not only advanced structural analysis but also close coordination with façade, MEP and other building systems to ensure that all components can accommodate movement over time. This level of integration requires structural engineers to play a central role in integrating these systems. The episode also explores the realities of construction, procurement and cost in tall mass timber projects. From rapid installation schedules to real-time problem solving in the field, success depended on continuous collaboration between the design team, contractor and fabricator. Lessons learned from Ascent emphasize the importance of early design clarity, detailed coordination and strong partnerships to reduce uncertainty and achieve competitive pricing. As the industry evolves, these insights are shaping how future tall timber buildings are conceived and delivered. Inside the Episode Hero Image: Use an Ascent glamor shot Key Insights: Ascent established a new precedent for tall mass timber. The project serves as a critical benchmark for code development, design strategies and future high rise timber buildings. Tall mass timber requires advanced understanding of structural movement. Greater elastic shortening, creep and moisture related effects must be accounted for across all building systems, not just the structure. The role of structural engineers is central to project success. Engineers are deeply involved in code strategy, fire performance, constructability and coordination across disciplines. Early coordination reduces risk and cost uncertainty. Well-developed design documentation and clear system integration improve contractor confidence and lead to more accurate pricing. Real time collaboration is essential during construction. Fast paced installation requires immediate problem solving and strong communication between field teams and designers. Procurement strategy impacts project success. Providing clear and detailed design information early helps manufacturers deliver more competitive and reliable pricing. Hybrid systems represent the next evolution of tall timber. Combining mass timber with materials like concrete can optimize performance, cost and constructability. Key Hero Image: Use gif of the Ascent model coming together. What You’ll Learn: Design and delivery process of Ascent MKE How mass timber design considerations differ from steel and concrete Vertical movement in mass timber IBC 2021 and strategies for code variances and AHJ approval Connection design and detailing best practices Accurate early timber pricing Hybrid timber systems What You’ll Learn Hero Image: TBD Use one of the interior shots from the Ascent page.

In this episode, hosts Paul Becker and Kristina Rogers talk with Doug Schweizer about how proprietary systems are transforming mass timber construction through the lens of the Under Armour Global Headquarters, a 280,000-square-foot office building. The discussion highlights how proprietary connections introduced by timber manufacturer binderholz streamlined fabrication, reduced installation time and delivered measurable cost and schedule savings. The key to success was the willingness of the entire design and construction team – including Gensler, Whiting-Turner and Seagate Mass Timber – to collaborate closely. A central theme is the importance of proactive and continuous coordination when working with proprietary systems. Engineers must invest significant time in understanding design assumptions, reviewing calculations and collaborating closely with manufacturers. Frequent communication, detailed submittal reviews and early engagement allow teams to build confidence in the system while ensuring it integrates seamlessly with architectural intent and other building systems. The episode also examines how collaboration across the full project team influences success. Engineers act as a bridge between manufacturers, architects, and contractors, helping translate proprietary concepts into buildable solutions. When all parties are aligned and open to new approaches, proprietary systems can enhance both speed and efficiency.

In this episode, hosts Paul Becker and Kristina Rogers talk with Chris Williams about how hybrid mass timber systems are emerging as a practical solution for low-rise residential construction, particularly in markets already reliant on light-frame wood buildings. Rather than fully replacing traditional systems, mass timber is introduced strategically in elements such as floor slabs and shafts. This approach creates a flexible entry point for developers looking to adopt mass timber without fully committing to all-timber structures. And low-rise structures can take advantage of IBC Type 3 and Type 5 code requirements, which are simpler and less costly to achieve than Type 4 construction.* Two projects, the Mayflower Hill Residence Hall at Colby College and Goldfinch Lofts, an affordable housing development in Des Moines, Iowa, illustrate the discussion. Chris highlights how prefabrication of mass-timber components off-site is enabling faster on-site assembly with smaller crews. But this shift requires strong up-front coordination, particularly for MEP systems. Early collaboration and detailed planning become critical to fully realize the benefits of speed and efficiency. The conversation also explores the benefits of having the structural engineer take on the role of special inspector during construction. The episode examines how mass timber can address broader industry challenges, including labor shortages and the need to accelerate housing delivery. As adoption grows, hybrid systems offer a scalable model for both affordable and market-rate housing. * In the International Building Code (IBC), mass timber (or “heavy timber”) is categorized as Type 4 construction. Type 3 (“ordinary”) combines noncombustible exterior walls with combustible interior elements. Type 5 (“wood-frame”) uses conventional light-wood studs and joists with plywood sheathing.

In this episode, hosts Paul Becker and Kristina Rogers talk with Alejandro Fernandez about how the role of the engineer has evolved into a true strategic partnership within developer-led mass timber projects. When engaged at the earliest stages, experienced engineers can prevent complications by sharing effective approaches to schedule, accurate early pricing, insurance strategy, and permitting pathways. They can also help shape project teams and guide decision-making around delivery methods. This early collaboration ensures that all stakeholders are committed to designing for mass timber from the outset. A major focus is placed on how close coordination among all team members directly impacts project feasibility and cost. Open communication and collaboration among architects, engineers, manufacturers, erectors, and contractors early on can identify cost drivers, enabling the team to optimize the design to lower costs. The episode explores strategies for working with jurisdictions to facilitate approvals for code variances, using the real-world example of Ascent. It also covers ways in which the use of mass timber reduces construction costs, offsetting the cost of the material itself.

Interested in designing or building with mass timber but unsure where to start or if it’s right for your project? This podcast provides practical information on how to efficiently and cost-effectively integrate mass timber into projects of every size and type. Owners, developers, architects, and engineers will learn how to overcome concerns about cost, code compliance, insurance issues, fire safety, acoustic and vibration challenges, and more. Hosts Paul Becker and Kristina Rodgers talk with experts in mass timber analysis, design, and construction to uncover effective strategies, best practices, and lessons learned from a large portfolio of projects. They discuss ways the advantages of mass timber – sustainability, low embodied carbon, biophilic benefits, construction efficiency, and circularity – can be successfully incorporated into a widening array of projects, including commercial buildings, high- and low-rise residential, healthcare and labs, academic buildings, data centers, cultural and arts centers, sports and recreation, aviation facilities, and bridges and transportation infrastructure.