< Previous10 Pushing the Envelope Canada • Fall 2025 FEATURE The fabrication of these living struc- tures represents a significant leap forward in material science and experimentation in the context of building materials. They were produced using a novel biofabrica- tion platform developed at ETH Zürich, en- abling the creation of living materials at an architectural scale – a first of its kind. This technological synergy allows for the precise engineering of environments where these cyanobacteria can thrive, transforming passive building components into active agents of environmental remediation. The Living Room Collective, led by Can- adian architect and biodesigner Andrea Shin Ling, alongside core team members Nicholas Hoban, Vincent Hui, and Clayton Lee, embodies a profound shift in design philosophy. Their work is the culmination of four years of collaborative research, focused on harnessing the fundamental physical properties and functions of living systems to develop sustainable, intelligent, and resilient materials and technologies. Picoplanktonics is a powerful articulation of their “ecol- ogy-first ethos,” proposing environments co-constructed with living systems to re- mediate the planet rather than exploit it. Amidst the escalating global climate crisis, the Living Room Collective’svision is clear: to move society away from ex- ploitative systems of production towards regenerative ones. By leveraging ancient biological processes alongside emergent technologies, they are rethinking tradition- al building principles, prioritizing ecological resilience and the well-being of all species, not just human survival. This project chal- lenges us to consider how we can co-oper- ate with nature, designing spaces that act- ively contribute to the health of our planet. The exhibition at the Canada Pavilion in Venice this year is as much a part of the ex- periment as the material itself. Visitors en- counter large-scale 3D-printed structures, which were originally fabricated in the ETH Zürich laboratory. The unique Picoplankton- ics experience stems from the deliberate adaptation of the Canada Pavilion to provide the precise conditions – enough light, moisture, and warmth – for the liv- ing cyanobacteria within the structures to grow, thrive, and visibly change over time. For the duration of the Biennale, dedicat- ed caretakers are onsite, tending to the struc- tures. This emphasis on care and stewardship is not just a practical necessity but an essen- tial element of the design narrative. It under- scores the reciprocal relationship between living structures, the built environment, and humans, highlighting that a truly regenera- tive system requires ongoing attention and collaboration. The pavilion transforms into a dynamic, evolving ecosystem, demonstrating the challenges and rewards of integrating biological processes into architectural prac- tice and into the lifecycle of a building. As global carbon emissions continue their relentless rise, Picoplanktonics offers a compelling vision of how a regenera- tive system of construction could operate. This ongoing experiment is centered on Living Room Collective: Picoplanktonics, Canada Pavilion at the Venice Biennale, 2025. Commissioned by the Canada Council for the Arts.Building Science Association of Ontario 11 FEATURE leveraging the inherent capabilities of living organisms to create responsive, adaptive building systems. The implications for fu- ture use cases are vast and transformative. Imagine building envelopes that active- ly purify the air, absorbing carbon dioxide and releasing oxygen. Consider interior surfaces that regulate microclimates, inter- acting dynamically with their surroundings to enhance comfort and energy efficiency. This bio-functional material could be inte- grated into facades or interior partitions, turning every surface into a potential car- bon sink. Beyond large-scale architectural projects, the principles demonstrated by Picoplanktonics could inspire modular, de- ployable structures for disaster relief, or even contribute to self-sustaining urban farming systems. The Living Room Col- lective’s work pushes the boundaries of construction, material sciences, and en- vironmental performance, asking critical questions about how we fabricate bio- logical architecture, the conditions of environmental stewardship, and strategies to instigate this regenerative approach at building, urban, and regional scales. Picoplanktonics is more than an exhib- ition; it’s a powerful statement about the symbiotic relationship between humanity and the natural world. It invites us to en- vision a future where our buildings are not just shelters, but active participants in the planet’s healing, embodying a profound commitment to ecological resilience and a truly living architecture. ■ Dorothy Johns, Ph.D., OAA, CPHC, is an Assistant Professor in the Department of Architectural Science at Toronto Metropolitan University and Director of the Catching Carbon Lab, an interdisci- plinary research ground advancing decarbonization strategies in the built environment. Dr. Johns’ research focuses on the performance, durability, and integration of bio-based materials in building envel- opes. Her lab is currently collaborating with Northern Indigenous communities to co-develop a dynamic modular housing framework that is high-performance, low-carbon, and culturally responsive, supporting climate- and social-resilience. She is also the founder of Woodhouse Studio, an architectural practice driven by participatory and community-engaged design to achieve low-carbon buildings. Steph Tzanis, EIT, M.A.Sc, CPHC, is a Building Science Consultant at WSP, and is passionate about decarbonizing the built environment without compromising on architecture or design. Their master's thesis, completed in 2023, was focused on circularity and, specifically, design for disassembly. Photo courtesy of Valentina Mori.12 Pushing the Envelope Canada • Fall 2025 FEATURE By Matt Charbonneau, Edison Engineers Inc. A growing number of condominium buildings are em- barking on large-scale window replacement projects. These initiatives are driven by a mix of necessity: deteri- orating window components, persistent water leaks, and poor energy performance. While these projects are often complex and costly and can significantly impact residents’ well-being and prop- erty value; they also represent a rare, once-in-a-generation chance to transform the aesthetic and functional identity of a building. THE CASE FOR MOVING BEYOND LIKE-FOR-LIKE Many condominium boards take a conservative approach to window replacement, opting for similar replacements in type and configuration. This approach often misses the chance to add meaningful value. Reconfiguring operables, adjusting sightlines, or updating frame styles, can greatly enhance both living comfort and curb appeal. Because such improvements are only practical dur- ing full replacements, investing early in design studies, renderings, mock-ups, and stakeholder engagement is essential. This process builds community confidence and avoids costly setbacks caused by misinformation or misunderstanding. DESIGN CONSIDERATIONS AND OPPORTUNITIES Two of the most significant and widely understood design con- siderations involve double vs. triple glazing and operable window type, sliding vs. hinged. The choice between double and triple glazing directly affects thermal performance, energy efficiency, and occu- pant comfort, with triple glazing offering superior insulation at high- er cost and with greater weight implications. Similarly, shifting from traditional slider-style operable units with fin-and-pile weatherstrip- ping to awning/casement operables with gasket-style weatherstrip- ping can dramatically improve air and water tightness, noise control, ease of operation, insect resistance, and long-term durability. These two considerations establish the baseline for perform- ance improvements and should be carefully evaluated in every replacement project. The following design considerations are less understood and can have significant impact. 1. Glass coatings Selecting the right low-emissivity (low-E) coating or tint is key to balancing efficiency, comfort, daylight, and aesthetics. While modeling software lists over 6,000 glass types, most fall into a few categories. Choosing optimal coatings over common defaults can greatly impact results. Different coatings may also be applied to various elevations or areas to better meet client goals; this re- quires strict quality control to ensure accurate implementation. Often misunderstood low-E coatings are not just for managing summer cooling – they also reduce radiant heat loss in winter and significantly improve insulation. 2. Frame material As of 2025, combustible window frames are permitted in On- tario provided some key details are followed such as non-com- bustible floor-to-floor separation. This was captured in the 2024 Ontario Building Code, effective in 2025. Prior to that, restrictions on combustible window framing were in effect since 1965. This change provides the opportunity for fiberglass frames to be used in high-rise window-wall for instance. Fiberglass frames provide the opportunity for improved thermal performance with strengths suitable for window-wall or larger window applications. 3. Window reconfiguration Reconfiguring the arrangement of fixed and operable sections can enhance functionality and maximize daylight and views. For example: • Shifting operable units towards perimeter of the rough opening – away from main viewing area while also considering height of crank for ease of accessibility. Rethinking Condominium Window Replacements: Design Considerations and Opportunities An exposed slab edge around a building. Photos courtesy of Matt Charbonneau.Building Science Association of Ontario 13 FEATURE • Modifying frame patterns and proportions can refresh the build- ing’s aesthetic and make facades look more contemporary. Even modest reconfigurations can modernize both the interior and exterior experience with minimal to no impact on cost. 4. Exposed slab edges Many older buildings face the challenge of exposed slab edges, which act as major thermal bridges and reduce overall performance by increasing energy use, creating comfort issues, and elevating con- densation risks. These exposed reinforced concrete elements can often experience deterioration. Window replacement projects can help address these issues by carefully designing the in/out position of the window system and incorporating slab edge bypasses. This strategy improves both thermal performance and the long-term durability of slab edges, while also achieving a sleeker, more con- sistent vertical aesthetic. 5. Frame style A wide range of window frame products are available in Canada, each with subtle differences in design and cost. When repeated across an entire building façade, these variations can significantly in- fluence both aesthetics and views. Understanding and demonstrat- ing these distinctions is essential to identifying the best solution for the community. For example: • Frame-to-frame joinery: H-clip connections versus male-female joinery can reduce width of visible framing to enhance daylight and maximize views. • Operable hinges: Hinges may be exposed or concealed; for in- stance, some awning windows show top-mounted hinges, while others conceal them along the side. These choices affect sash size limits and may increase the risk of operational issues de- pending on type and dimensions. • Sash cross-section: Flat sash profiles can appear wider and more prominent, whereas angled or jogged profiles reduce vis- ual weight for a sleeker look. Engaging owners in these discussions and using samples, ren- derings, and mock-ups ensures the community makes informed choices and achieves the greatest benefit from these large-scale projects. 6. Importance of visualization and resident engagement Visualization is one of the most effective ways to build consen- sus and ensure project success. Renderings, samples, and mock- ups help boards and residents see how design choices will affect appearance and views. Clear visuals also promote transparency by making trade-offs between cost, design, and performance easier to understand. CONCLUSION: SEIZE THE OPPORTUNITY Replacing windows in a condominium building is not just a main- tenance obligation—it is an opportunity. It’s a rare chance to redefine the building’s image, improve the daily lives of residents, and protect the value of the investment for decades to come. By moving beyond like-for-like thinking and embracing a detailed design process with community engagement can ensure that this once-in-a-generation project leaves a lasting positive legacy. ■ Matt Charbonneau is a Principal and Shareholder at Edison Engineers Inc. He is passionate about im- proving people’s lives and adding value to the built environment by developing durable, comfortable, energy efficient, and aesthetic repair solutions. Depiction of window reconfiguration.Building Science Association of Ontario 15 FEATURE T he transition to high-perform- ance and low-carbon building envelopes is essential for a cli- mate-resilient future. Windows, often the weakest link in the envelope’s thermal performance, play a pivotal role in deter- mining both operational energy use and life cycle greenhouse gas emissions. To evaluate the relative carbon impacts of double- and triple-glazed windows, VETTA Building Technologies conducted a comparative life cycle assessment (LCA) using a real-world retrofit case study in Etobicoke, Ontario. The case study home was a 120 m² single-family home with an electric air-sourced heat pump and is therefore modeled according to the Ontario electricity grid. No other retrofit measures were taken besides replacing the windows. The analysis involves a comparison between two window profiles – a double- and a triple-glazed unit. Both windows are solid wood aluminum-clad windows made from mass timber. The wood is sustainably harvested under the Pro- gramme for the Endorsement of Forest Certification(PEFC). Additionally, the win- dows have argon-filled glazing, warm- edge spacers, low-E coatings, compres- sion seals, German steel mechanics, multi-point locking systems, and heavy- gauge aluminum exterior cladding. The study compares a VETTA ELITE S68 in a double-glazed configuration to an ELITE E92 Phius certified, and PHI validated triple-glazed unit. The operable double-glazed unit has a U-value of 1.17 W/m²K, while the operable triple-glazed unit achieves 0.72 W/m²K (see Figure 1) – a 38 per cent increase in thermal perform- ance. In addition, the triple-glazed unit By Carolyn Sedgwick and Kim-Marie Degenkolb, VETTA Building Technologies Inc. Beyond Double: How a Third Pane Boosts Building Performance and Cuts Carbon Window installation by Bridgemont Properties. Photo courtesy of Tharanga Ramanayake.16 Pushing the Envelope Canada • Fall 2025 FEATURE has one additional gasket, which increas- es the airtightness of the unit to begin, we reviewed the embodied carbon stages of the product's life cycle, which includes the emissions from raw material extraction to manufacturing.. The triple-glazed window carries only a seven per cent higher em- bodied carbon footprint; 70.20 kgCO 2 e per square metre compared to 65.70 kgCO 2 e per square metre for the double-glazed equivalent. This difference is attributed, first, to the E92’s additional glass panel, spacer, and gasket. Secondly, the E92’s larger wood mass offers a greater biogenic GWP/carbon storage benefit due to the thicker GLT frame – 92mm versus 68mm. Next, we turned our attention to the product's operational phase, specifically its ability to reduce a home's energy use and emissions from heating and cooling. The Operational performance modelling be- ginning in the first year is 586.59 kgCO 2 e/a for the triple-glazed windows and 807.48 kgCO 2 e/a for the double-glazed windows – a difference of 27 per cent in favour of the triple-glazed units. Because carbon performance can only be accurately understood when both embodied and operational impacts are assessed over a defined time period, we applied a carbon use intensity framework that combines upfront carbon with long- term operational emissions in our an- alysis. When projecting over the 60-year service life of the windows, the carbon use intensity savings for the entire home amount to 13,248.90 kgCO 2 e in favour of triple glazing. This is equivalent to the carbon emission of 552 propane cylin- ders used for home barbeques accord- ing to Natural Resources Canada’s GHG equivalencies calculator. If a lower tier double-glazed window would be used in comparison, the number would increase exponentially. Additionally, the earlier mentioned lower embodied carbon benefit of the double-glazed windows is only relevant during the first three to four months – a short carbon use intensity payback per- iod. Once both embodied and operation- al carbon are considered together, this advantage is quickly surpassed. After this brief carbon use intensity payback Figure 1: Window Performance Tiers. Graphics courtesy of Kim-Marie Degenkolb.Building Science Association of Ontario 17 period, the triple-glazed window deliv- ers a consistently superior carbon out- come over the remainder of its service life (see Figure 3). These results support the prioritization of high-performance windows in retrofit projects, especially in climates similar to southern Ontario’s, where both heating and cooling loads are significant. After the first three months of home occupancy, triple glaze will outperform double glaze in combined embodied and operational carbon emissions. Tri- ple-glazed high-performance windows provide superior thermal comfort by maintaining more stable interior surface temperatures, reducing drafts, and mini- mizing cold-weather condensation. They enhance resilience by mitigating heat loss during winter power outages and heat gain during summer heat waves. Addition- al advantages include improved sound in- sulation and indoor air quality. The findings also reinforce a broader principle in building science: high-per- formance windows improve overall envelope performance exponentially. As Christine Williamson demonstrates in Why Glazing Matters, even a very high-performing wall assembly can have its effectiveness significantly reduced when paired with low-performance glaz- ing, whereas high-performance glazing enhances whole-envelope performance. In the Etobicoke case study, replacing double glazing with triple glazing im- proved not only the modelled energy use but also reduced the carbon intensi- ty of the building over its service life. In addition, recent research on car- bon-storing natural materials titled Emissions of Materials Benchmark As- sessment for Residential Construction by Chris Magwood, Builders for Climate Action, highlights that selecting low- er-carbon natural or biogenic materials is crucial to decrease the life-cycle car- bon payback. Using PEFC-certified wood, harvested from sustainably managed Figure 3: Carbon Use Intensity. Figure 2: Embodied Carbon (A1-A3). FEATURE After the first three months of home occupancy, triple glaze will outperform double glaze in combined embodied and operational carbon emissions. 18 Pushing the Envelope Canada • Fall 2025 FEATURE forests, protects ecosystems, wildlife, and watersheds. Additionally, timber sourced from sustainably managed for- ests serves as an effective form of car- bon capture and storage, a strategy ex- plicitly recognized and recommended by the UN Intergovernmental Panel on Climate Change. In summary, the study demonstrates that in cool-temperate climates, tri- ple-glazed, high-performance windows deliver clear carbon advantages over their double-glazed counterparts. De- spite a slightly higher manufacturing footprint, their short payback period and substantial lifetime emissions reduction position them as essential tools in the drive toward net-zero and climate-resili- ent buildings. ■ Carolyn Sedgwick, Vice President of VETTA Building Technolo- gies Inc., is a trailblazer in sustainability, climate change, and busi- ness transformation, with over 30 years of experience delivering innovative solutions that drive triple bottom line benefits. She has been recognized with the Canada Clean16/Clean50 award for her leadership in advancing carbon accounting and climate-related financial disclosure. Carolyn started her career as an Environ- mental Scientist with the Ontario Ministry of the Environment and Environment Canada before transitioning into corporate roles focused on driving meaningful change. Prior to joining VETTA, she served as AVP Corporate Strategy and Sustainability at Canadian Tire Corporation, Global Director of ESG at Clariant AG, and Director of Business Transformation at the Ontario Pension Board. She holds a bachelor’s degree in environmental studies from the University of Waterloo and a master's degree from Dalhousie University. Kim-Marie Degenkolb is a Project Manager at VETTA Building Tech- nologies Inc., specializing in high-performance residential projects. With a background in building science and architectural design, she combines technical expertise with a deep commitment to sustain- ability. Her research focuses on operational and embodied carbon estimation and life cycle analysis, using tools such as the OneClick LCA platform, BEAM Estimator, and advanced energy and envelope mod- eling software. Kim-Marie has explored retrofit strategies in depth, including over-cladding versus targeted interventions such as win- dow replacement or installing air barriers without added insulation, in collaboration with Sustainable. She has also presented her “car- bon as currency” research at multiple conferences and virtual events, advancing industry dialogue on accurate and actionable carbon ac- counting. Driven by the goal of creating a resilient, low-carbon future, Kim-Marie continues to explore emerging building technologies and methods that enhance the precision of carbon measurement and support meaningful climate action. VETTA’s Ronny Koeppe, Service Manager for VETTA Building Technologies Inc., and Kim-Marie Degenkolb.Building Science Association of Ontario 19 FEATURE Y ou may be familiar with a traditional curtain wall parapet, featuring an opaque spandrel assembly outboard of a roof curb. But have you heard of the “fly-by” curtain wall parapet? Instead of an opaque parapet, the fly-by curtain wall parapet incorporates transparent glass into the parapet, creating a “glass-box” effect which is visually consistent with the building glass below; however, this desirable feature is not without its challenges. Air and water barrier continuity between a roof and a traditional opaque parapet is typically achieved by overlapping waterproofing membranes and flashings between the spandrel and the curb (Fig- ure 1). In contrast, the fly-by curtain wall parapet is made water- tight by integrating flashings with the roofing membrane near the roof surface, while the vision glass continues above. There is less industry knowledge and guidance regarding design of fly-by cur- tain wall parapets, particularly with limited ability to conceal roofing materials. This article explores design considerations, detailing op- tions, and coordination techniques to assist you in navigating the technical complexities of a transparent parapet. DESIGN CONSIDERATIONS Roof assembly type and programming Fly-by curtain wall parapets can integrate with any roof assem- bly type, including protected membrane roofs (where the insu- lation is installed on top of the waterproofing membrane, Figure 2) or conventional exposed membrane roofs (where the roofing membrane covers the insulation, Figure 3). If the fly-by curtain wall parapet is used to satisfy IBC Section 1015 code requirements for a guardrail, for example in an amenity roof terrace, it must be not less than 42 in. high measured from the adjacent walking surface. Coordinate the fly-by curtain wall parapet height with the high point of a sloped roof surface (in an exposed assembly) to meet guardrail height requirements. CURTAIN WALL CONSTRUCTION METHOD Curtain walls are generally designed and constructed as either a stick-built system (Figure 4) or a unitized system (Figure 5). The Whole Building Design Guide defines a stick-built curtain wall as a system where “curtain wall frame (mullions) and glass or opaque panels are installed and connected together piece by piece” and a unitized system where “the curtain wall is composed of large units that are assembled and glazed in the factory, shipped to the site and By Maria Raggousis and Sam S. Zalok, Simpson Gumpertz & Heger WhereGlass Meets Roof: An Introduction to Fly-By Curtain Walls and Parapets Figure 1: A detailed look at an opaque curtain wall parapet. Graphics courtesy of Maria Raggousis. Figure 2: A detailed look at of a protected membrane roof assembly. This article was originally posted on buildingenclosureonline.com. Figure 3: An example of a conventional exposed membrane roof assembly.Next >