This article is part of a special report on Climate Solutions, which looks at efforts around the world to make a difference.
There was a time, including when Martin Henn’s grandfather and father were at the peak of their careers, when many architects lived by a simple creed: bigger was better. But with a growing awareness of how that thinking contributes to the greenhouse gas emissions that are linked to climate change, a new vocabulary has sprouted in many firms: sustainability, circular economy, organic design.
That is the kind of language that Martin Henn, 41, said he brought into the German architecture firm HENN that his grandfather, Walter Henn, founded in Dresden in 1947 and that his father, Gunter, joined in 1979 and later expanded into Munich. It is in line with a growing awareness among architects about the need to design in ways that help, rather than hurt, the environment.
Switching building practices has enormous potential to reduce CO2 emissions. Construction and operations generate nearly 40 percent of the CO2 emitted globally each year, with materials and construction alone accounting for 11 percent of emissions, according to Architecture 2030, a think tank based in Santa Fe, N.M. Just three popular materials — concrete, steel and aluminum — contribute 23 percent of all emissions.
Mr. Henn, a managing director of HENN, joined the family firm in 2008 after working at Zaha Hadid Architects in London and Asymptote Architecture in New York. He now oversees the design of all of HENN’s projects. He said he has approached his role with the intention of making a positive impact on the environment with every building his company conceives.
“Architecture is a powerful tool that can actually help mitigate climate change,” he said. “The opposite tends to be the general perception, but definitely doesn’t have to be the case.”
HENN has more than 350 employees and has worked on the Merck Innovation Center in Darmstadt, Germany; the Volkswagen Transparent Factory in Dresden; and a Hyundai Design Center in Seoul, among others. The firm has been involved with more than 70 buildings, including Westlake University in Hangzhou, China, and the renovation of the Gasteig, a cultural center in Munich.
Below are excerpts from a recent interview with Mr. Henn, who spoke to The New York Times from Berlin, where he is based. This interview has been edited and condensed.
HENN is a long-established architecture firm. How did its priorities change when you joined?
I come from a younger generation that understands the urgency of our climate crisis. Limiting the environmental impact of our work and making a positive impact became a priority. I also brought a new design vocabulary to the firm.
Can you explain how sustainability factors into the structures you design?
The most sustainable building is one that uses the least amount of building materials and operational energy, is made from materials with the lowest carbon footprint and has the longest life span. HENN considers all three factors in every design.
We believe in less demolition and more repurposing or renovation. Around one-third of our projects are renovations.
New construction, when necessary, should anticipate the future with designs that are easy to reuse or disassemble. Our buildings also use local and recycled materials; more timber and less concrete because timber is one of the most sustainable building materials in the world; and facades that let the building breathe like an organism, which keeps them cool in the summer and warm in the winter without the use of air-conditioning or heaters.
Can you tell us how two of your most recent projects considered the environment?
We recently overhauled the HVB Tower in Munich, which was built in 1981. The goal was to preserve the exterior while transforming it into an energy-efficient building. We removed, cleaned, perforated and reinstalled the original facade panels to create a double-layered skin.
The windows of the new inner layer can be opened for fresh air. This is unusual in tall buildings, but it reduces cooling costs and is better for the environment and healthier for the occupant. The renovated building achieved LEED Platinum certification.
Another example is the Brunner Innovation Factory, in Rheinau, for the furniture company Brunner. Inspired by the construction details and natural materials of their products, we designed a lightweight, minimal structure made from sustainable timber that is designed to be easily disassembled and reused.
Please talk about how some of your upcoming projects are sustainable.
We are undertaking an ambitious modernization of the Gasteig, a cultural center in Munich that opened in 1985. Our proposal reuses as much of the original structure as possible — a radical idea in the context of today’s culture of disposability.
We are removing and reusing bricks as a form of CO2 storage; using solar panels for energy and the nearby river for passive heating and cooling strategies; and using the roof as an urban farm whose produce will be used in Gasteig’s restaurant.
HENN is also working on expanding the University Hospital in Aachen [Germany]. We’re leaving the original building and the landscape visually untouched since our extension happens almost entirely underground.
The ICU, operating rooms and common spaces are organized around a series of light wells and sunken gardens that provide plentiful sunlight, natural ventilation and access to green spaces within the hospital.
As you’ve designed buildings and helped see them realized, can you share what challenges you’ve encountered when it comes to sustainability?
The imperative of faster-better-stronger still applies to the construction industry, which can mean defaulting to fast, familiar and cheap solutions. But building sustainably doesn’t mean a more expensive building, especially when you consider the lifetime costs, not just the construction costs.
Things that seem more expensive upfront will cost less in the long term: a double-layer facade, instead of a single layer, will decrease heating and cooling costs; the use of high-quality materials will prevent the need for repair and replacement; structural systems designed for disassembly can be reused again and again; and even LED lights last longer than regular lights.
What social responsibility do architects have to be more sustainable?
As architects, we have an urgent personal and professional responsibility to address building-related CO2 emissions. The most important thing we can communicate is that sustainability isn’t an afterthought or an add-on, it’s not just solar panels on a roof — it’s fundamental to the form-finding, the materials we use and the performance of a building and its components.
How can architects influence developers to use sustainable building materials to construct their structures? Is it their responsibility to do so?
One way to approach this is through the developer’s bottom line. Besides the long-term cost-saving benefits of adaptable buildings, circular construction and sustainable building materials, we can save time and money through modular and prefab [prefabricated] construction.
Developers are already interested in sustainability, it’s a much easier conversation to have now than it was 10 years ago. The next step is to move beyond the certification checklist, which comes at the end of the project, to identify how sustainability can motivate a project and be integrated from day one.
What are some construction materials that make structures more sustainable?
It’s best to use local materials that don’t need to be transported long distances and natural materials like wood, which is carbon-sequestering and renewable when harvested sustainably; surfaces made from clay or ceramics, a readily available material that has a natural pollutant binding effect and regulates interior humidity; and natural stone cladding which can be produced using zero-waste methods.