Meanwhile, in Brussels, Ken De Cooman is bringing valuable lessons learned from builders in Burundi, Ethiopia, and Morocco to help European architects transition to a less resource-intensive and renewable form of construction. 

Read every story from our 2025 Spring Issue:

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• Architecture
• Cities
• Industrial Design
• Interior Design
• Process
• Reuse
• Sustainability

• 2025 Spring Issue
• adaptive reuse
• Avinash Rajagopal
• Equitable Design
• Net Zero
• Sustainability Commitments

Renovation and addition projects tend to either emphasize the contrast between the old and new—sometimes rather fussily and didactically—or conceal the architect’s parti, presenting a new, temporally and spatially seamless whole. Opting out of this binary, a residential project in Quebec instead advances a more “ambiguous dialogue” between past and present, balancing continuities and novelties. Similarly, it incorporates highly modern climate and energy efficiency elements while maximizing the impact of older, existing strategies. 

Montreal-based architecture firm Pelletier de Fontenay took an almost scientific approach to understanding and adjusting the materiality of the existing house, located on a family’s grounds in the Eastern Townships outside of the city, a region characterized by rolling farmland and quiet country retreats. The original 1908 house was built with heavy, deep walls of mismatched stone—recalling a common building material found around Quebec—but with cement as mortar. The “logic” of the house’s structure “was sheer mass and weight,” says Yves de Fontenay, one of the firm’s founders, with the stone-as-aggregate structure essentially functioning as concrete walls “in terms of physics and engineering.” In the 1950s, the house was augmented with a new, boxy front porch addition—made of superficially contextual stone that mimicked the first house—that muddled the layout and turned its back on the surrounding farmland, woods, and pond. 

Harmonizing Project Goals with Sustainable Design Approaches

While working within the existing structures, the architects were guided by two overriding goals: Preserve as much as possible, and create an architecturally unique extension better connected to the landscape and sized for a large family. They wanted the project to operate within the context of the original house’s heft, materiality, and color without resorting to mimicry or excessive opposition. Heating and cooling costs were “astronomical,” de Fontenay recalls, so they’d have to use more passive strategies to increase its thermal performance and overall energy efficiency. “The most logical approach to blend everything together was to rework the surfaces,” de Fontenay says, and as for the durable, deep stone walls, “preserving this was an obvious choice.”

The result, a low-slung, parged-over addition with ample glazing, exhibits both a sharp formal break from the existing structures, and  uniformity with the house’s two volumes. Its horizontal form, institutional aesthetic, and smooth, contemporary surfaces are foils to the original structure’s messy stone composition, domesticity, and verticality. Beyond mere formal and aesthetic distinctiveness, de Fontenay says, the relatively shallow cantilever is calibrated to help limit thermal gain in the summer, while maximizing what natural warmth the sun does provide in the winter.

The addition is unified with the existing parts through a shared feeling of weightiness and a similar protective surface treatment: “Parging everywhere, inside, outside,” says de Fontenay. The firm worked with local artisans to develop a cement and lime parge that covers all structures, old and new, and tested it over the course of the year, ensuring it would bind properly and observing how it responded to the damp summers and severe winters. This treatment—an adaptation of the traditional technique—works in tandem with INTELLO membranes and locally sourced hemp in the interior walls, providing insulation against extreme temperatures and moisture while allowing breathability. “Humidity is a big component of comfort,” de Fontenay says, explaining that the wall liners ensure the house doesn’t function like a “closed bag.”

Embracing Nature within Interiors and Exteriors

The parging is also troweled on in the interior, where partially preserved oak wood floors and local limestone in the kitchen make for a spare, serene palette. The ’50s addition—envisioned then as a porch—was laid out a step below the original house’s floor-plate, so the architects decided to also set the new addition a few steps lower. One departure from the horizontal and sharp proportions characterizing the interior is a sinuous stair—also parged over, naturally—that collects and ventilates warm air in the summer. It distributes heat throughout the house in the winter, with the help of a mechanical heat recovery system.

Outside are more examples of the theme of continuity, with new flower beds and walls of local stone connecting to the landscape. The original basement level was bermed underground, which had previously jutted up awkwardly, further reorienting the complex toward horizontality and its surroundings. Full-height windows and sliding doors enable new visual connections to an adjacent, previously neglected pond and to some newly added vegetation, opening up the house to all the elements that typify this southeastern wedge of Quebec: farmland, forest, and countryside.

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• Preservation
• Residential

• Energy efficiency
• innovative construction
• Responsible Renovation
• Retreat
• Sutton House

The nuclear fusion reactions at the core of the sun convert four million tons of matter into energy every second—and only a small fraction of the energy produced by the hot, blazing star is needed to support all life on Earth. Humans, of course, have been developing mythological, religious, economic, and artistic narratives about the sun since the beginning of time. The gaseous object lies beneath the very concept of timekeeping itself. But while the sun has come to symbolize hope, creativity, and joy, in the light of today’s climate crisis, its all-encompassing, life-giving power and untamable heat can also evoke destruction and despair. 

“Solar energy needs a new narrative,” says German textile designer Shani Nahum, “one that moves away from the traditional focus on efficiency and the payback time of blue solar panels.” Her project The Boiling Purple aims to shift that understanding.  

Sun-Inspired Textiles and UV Radiation Awareness

Evolving out of her master’s thesis work at University of Art & Design Burg Giebichenstein Kunsthochschule Halle, The Boiling Purple is a textile collection consisting of five beach towels made of Econyl recycled nylon and Sunkolor, a material that changes from white to purple when exposed to high ultraviolet (UV) radiation. Incorporating the global UV index’s semiotic color scale and sun-inspired circular elements, Nahum turns a functional item into a poetic commentary on climate change, warning users of harmful UV exposure while also providing a reminder of the sun’s powerful duality as both life giver and potential threat. 

“UV radiation is one of the sun’s most significant characteristics, but it is naturally invisible to the human eye and other senses. UV radiation has both immediate and long-term effects on the skin and eyes, as well as environmental implications,” Nahum explains. “While The Boiling Purple doesn’t directly involve solar technology, it does engage with the sun’s properties as a central element, using them to provoke thought and raise awareness.” 

Textiles that Illuminate the Climate Crisis

Nahum is just one of many contemporary designers creating textiles that shed light on the climate crisis. For Amsterdam-based Yvonne Mak, textiles are also a medium for provoking thought and inspiring action. Her surreal series of curtains titled Imprint captures “how the sun’s impact, much like climate change, leaves an indelible impression on objects and landscapes, reminding us of the passage of time and the consequences of our actions,” she wrote in an artist statement for Dutch Design Week 2024. Her sun-bleached curtains mimic the slow fading of a textile, creating an illusion of windows left in place for decades. The effect is haunting and evocative, inviting viewers to consider how climate change gradually impacts our lives. “The curtains serve as a metaphor for the way climate change slowly intrudes into and alters our everyday lives. As global temperatures rise, homes and living spaces increasingly need to adapt to the changing environment.”

While Mak’s and Nahum’s work evokes symbolic and data-driven narratives, other designers are focusing on blending expression and function, integrating solar energy into textiles themselves. Dutch designer Pauline van Dongen notes, “Textiles have such a tactile, human quality, and combining that with solar energy allows us to reimagine what a ‘functional’ material can be—something that’s not just technical but also expressive, inviting, and imaginative.”

Textiles that Give Comfort to Communities

Her studio’s project SUNTEX is a lightweight, woven, solar textile designed to transform facades, awnings, and tents into energy-generating surfaces. The new material, developed with Utrecht, Netherlands–based design and engineering consultancy Tentech, is made by weaving thin, organic photovoltaic (OPV) film panels and high tensile-strength yarn, creating a flexible, modular material that can harvest solar energy while providing passive sun shading. “I imagine a future where materials like SUNTEX transform the way we see and experience energy in our surroundings—where buildings and public spaces come alive with textiles that shade, cool, and generate power, while adding to the aesthetic value of the space,” van Dongen says. The studio is currently at work on realizing a full-scale pavilion with the material, set to be completed this summer. 

Harnessing solar power can improve thermal comfort not only at the building scale but also at body scale. Dutch product designer Mireille Steinhage has created a heated blanket designed to address the needs of people in emergency situations. Solar Blanket uses the sun’s energy to generate warmth and electricity, providing comfort for those struggling with energy costs or homelessness. Modular pleating allows the blanket to adapt for individual or group use, while a built-in solar panel charges a portable power bank, enabling users to stay warm and power other devices off the grid. While the blanket was designed for the U.K. market, Steinhage sees enormous potential for it to be scaled and produced for disaster relief efforts worldwide. “By allocating a percentage of sales for charitable aid, we aim to donate blankets to charities, allowing the purchasing power of this group to help others in need,” she explains. 

A New Age of Climate Responsive Textile Design

Together, these products and projects weave a story of how solar textiles are transforming climate-responsive design. “These developments feel like a shift toward making solar energy more personal, more integrated into our environments and our lives,” van Dongen notes. “In the long run, I believe that designing with the sun can make us a humbler part of nature again, rather than ruling over it in a human-centric way. Solar textiles should go beyond just solving technical problems; they should evoke curiosity, inspire creativity, and invite interaction.”

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• Education

• Climate Adaptation
• Construction Materials
• Lauren Jones
• Rain Screen
• Rice School of Architecture

Defined by jagged-edged panels with imperfect textured surfaces, the One Side Sawn furniture series features pieces laser cut from an aluminum “crust,” material trimmed from cast aluminum blocks during production. “We wanted to show this gnarly, raw, and brute side to aluminum to remind people that this went through an immense amount of energy and processes,” says Rouff. 

Objects Designed To Be Easily Packed, Disassembled, and Recycled

The studio carefully planned the cuts to ensure that every single part of the crust was used, resulting in 11 irregularly shaped furniture pieces—ranging from side tables and shelves to a sideboard and mirrors. The larger pieces were designed like flat-pack products, easy to assemble using screws, with some implementing a three-way contact-point system or a small support bracket to ensure stability. “The pieces have a bizarre aesthetic loaded with a lot of backstory and research—statement pieces that challenge what we expect of materials around us,” says Rouff. 

Today, the studio continues exploring and revisiting other materials. Currently on the boards: new architectural products composed of slag and mirrors made from recycled silver poured onto glass. 

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• Making
• Manufacturing

• Aluminum
• Art and Craft
• Construction Materials
• Sheila Kim
• Studio ThusThat

Developing a Materials-First Design Strategy

Begun in 2020, the K.118 reconversion project in Winterthur, commissioned by the Abendrot Foundation, served as Buser’s watershed opportunity to study the real potential of reuse in architecture. Baubüro and a team from the Zurich University of Applied Sciences tested a methodology that inverted the conventional building process, beginning with an inventory of available materials for reuse, and allowing that to determine the final shape and form of the building. The external steel staircase was originally in an office building in Zurich; steel beams in the main hall once structurally supported a supermarket distribution center in Basel. Alongside these elements, the K.118 features natural materials, such as wood, straw, and clay. The university team evaluated the process upon its completion and concluded that the reuse strategy saved 60 percent of the typical CO2 emissions in a regular planning and construction process. 

“That’s when I started to get really nervous,” Buser tells me, explaining both how excited and apprehensive she was to share these findings as far and wide as possible. She embarked on a tour that included more than 100 lectures worldwide while also founding Zirkular, or Circular, an engineering and planning company that has changed the attitude toward reuse in Switzerland. Zirkular employs 100 people and sources material for reuse from buildings, demolition sites, and donors all over the country, matching supply with demand while also supporting architecture offices, urban planners, and policymakers in their reuse planning journeys and leading both small-scale workshops and higher education programs. 

Reuse Meets Architectural Demand

Three decades into her reuse crusade, public opinion has changed, Buser says, and now, “everybody wants to [do reuse], but they don’t know how.” Zirkular has found itself advising large companies with a lot of real estate. “The advice we give is: Keep your own stuff for your future construction,” Buser tells me, while simultaneously pushing that anyone who is seriously invested in reuse should be ready to prefinance the dismantling of building components.

“Sometimes I say we should stop construction for ten years,” she notes, “and develop other ways to go about it, namely how to find material; how to classify it; how to check, test, and so on.” And is there enough supply of existing materials to meet the demand of construction projects? Buser points out that “the problem was never to get the material, but always to get it into use again.”

Buser Challenges the Statuo-Quo of Construction

Buser’s efforts have paved the way for what Charlotte Malterre-Barthes calls “more virtuous architectures.” Malterre-Barthes, who is an assistant professor of architectural and urban design at Swiss research university EPFL, has in recent years argued for a moratorium on new construction. She told me that, despite her reservations about reuse itself, given the difficulty of scaling up “due to its demands for perseverance and access to specific networks and legal-financial frameworks,” as well as “the risks of both greenwashing and the cannibalistic nature of reuse,” the momentum generated by Buser’s work is undeniable. “Her practice has tremendously influenced young practitioners who challenge the current demolition/new construction model, showing a way beyond both the climate and imagination crisis.” 

When asked about the source of her seemingly inexhaustible energy, the seventy-year-old Buser is pragmatic, stating that for every success story that kept her afloat, there were many unsuccessful ones along the road. She also acknowledges her family and her health as important factors. Undeterred, she keeps going forward, lighting the way for the rest of us. Activism, as we know, is work that never really ends.

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• Education
• Government
• Preservation

• adaptive reuse
• Circularity in products
• Construction Materials
• Martin Zeller
• Reuse
• Vera Sacchetti

A good specification can never be too specific, and now more than ever, the right product is likely the most sustainable. Considerations for responsibly sourcing stone are vast and varied, but stringent requirements need not hamper design possibilities.

Materials verified by third-party standards improve the baseline for the environmental performance of natural stone. In addition to providing detailed standards, the Natural Stone Institute’s Sustainability Standard verifies key aspects of natural stone production, while the Green Building Alliance lists stone materials meeting its own criteria. However, new materials are not always certified at the time of specification, so manufacturer transparency is key. Requesting life cycle assessment info and disclosures like Declare labels or Health Product Declarations provides insight into material composition. Additives like cement, fly ash, plastic, or asphalt are best avoided.

Click here for links to all natural stone specification standards and resources

Sustainably Sourcing Natural Stone

Accounting for the scale of mineral extraction is also an environmentally responsible step when working with a nonrenewable resource. While using local minerals is possible, the impact of mining local ecologies—from biodiversity loss to water contamination—must be accounted for as well. In addition to a list of natural stone sustainability resources, the Natural Stone Institute aggregates an exhaustive breakdown of sourcing and verifying quarries. If ethical supply chain and fair labor practices are of value, consider requiring a chain of custody to elevate process standards and verify that stone travels as sustainably as possible. 

With durability and life cycle included as end goals for the project, designing for disassembly is a dynamic solution. Minerals that sequester carbon, like lime, or upcycled minerals, like gypsum, are ideal for recyclability and more flexible application and customization. For greater insight, the Parsons School of Design’s Healthy Materials Lab maintains a list of recommended minerals that meet its rigorous evaluations across its many material collections.

The second floor of Cluster Zuid underwent a complete transformation, while an “eighth house” with an anodized aluminum facade was added. This fulfilled an element of van Stigt’s original design that was never realized and extended the building by over 32,000 square feet. 

BREEAM Excellent certified, the Herta Mohr building now offers 172,332 square feet of space, including more than 700 teaching spaces, two lecture theaters, libraries, work and meeting rooms, and common areas.

“About half of the building costs went towards new installations, with the other half allocated to structural changes,” says van Kampen, adding that around 70 percent of the original building materials were reused to minimize environmental impact. 

Reclaiming Heritage while Enhancing Energy Efficiency

The concrete columns, made in situ in the late ’70s from the demolished central house, found new life in the extension. “We cut them loose from the floors and moved them to the new extension without any problem. The concrete tested flawlessly, with no rusted steel inside. Its quality is outstanding—I’m confident it’ll last another 150 years,” says van Kampen, highlighting how repurposed materials align with the university’s future-proofing strategy.

The Sequoia redwood ceiling panels were repurposed as wall cladding in the atrium. They were carefully milled in collaboration with BWRI, a social development organization supporting individuals with disabilities and other employment barriers. The slats’ specific pattern allowed for prefabrication and installation, minimizing waste.

“We had around 65,000 square feet of ceiling wood available, but we used only around 43,000 square feet. Some of it is stored on-site, and we’re planning to repurpose it for our next project,” says van Kampen, whose firm is also tasked with revitalizing two buildings adjacent to Herta Mohr building.

Over 430 solar panels, green roofs, and a ground-based thermal storage system drive the building’s energy efficiency, making it the university’s first fully gas-free structure. This system alone will cut carbon emissions by 150,000 kilograms annually.

A Key Focus on Biodiversity and Biophilia

Biodiversity was also a key consideration. The design blends indoor and outdoor spaces with a butterfly garden, bird nesting spots, and insect habitats. The climate-adaptive front square mitigates heat and absorbs rainwater, promoting both social interaction and environmental well-being.

This balanced focus on long-term sustainability mirrors van Kampen’s approach to architecture. Despite the challenges posed by Cluster Zuid’s protected status, he advocates stricter preservation to minimize unnecessary demolitions, emphasizing that buildings should be valued as long-term assets.

Van Kampen concludes, “We should protect more buildings to prevent their demolition too quickly. Buildings aren’t disposable products to be discarded after a few decades.”

Video credit: De Zwarte Hond & Harryvan

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• Education
• Preservation

• Embodied Carbon
• Herta Mohr building
• Net Zero
• Petra Loho
• Responsible Renovation