The zinc roofing that has given Paris its iconic grey skyline for nearly two centuries is now in the spotlight for a bid to gain UNESCO Intangible Cultural Heritage status. The French Ministry of Culture has nominated the city’s zinc roofers and their craft for consideration at the UNESCO session in Asuncion, Paraguay, this December.

The artistry of these roofers, along with other ornamental craftsmen who have shaped Paris’s skyline, will compete with 67 other candidates aiming to join the ranks of globally recognized heritage sites like the Taj Mahal. According to Paris’s urbanism agency, Apur, the city has 128,000 roofs covering 32 million square meters, with 21.4 million square meters covered in traditional zinc.

Delphine Burkli, the mayor of Paris’s ninth district, has been a driving force behind the nomination, first proposing it in 2014. “Paris seen from above is unmistakably unique,” she said. However, the proposal has faced challenges, including a setback when Paris city hall withdrew its support, fearing restrictions on future construction if the roofs were listed.

The bid’s focus has shifted from simply preserving the roofs to highlighting the roofing profession itself, which is struggling with recruitment challenges. Each morning, Paris faces a shortage of about 500 roofers, according to Meriadec Aulanier of the trade union for plumbing and climate engineering.

The zinc covering most of Paris’s roofs has faced criticism for contributing to building overheating. Darker roofs absorb more heat, exacerbating the effects of increasingly intense summer heatwaves. A 2022 Apur study found that 42 percent of Paris roofs had poor heat reflection, leading to higher indoor temperatures.

Roofscapes, a French start-up from MIT, tested zinc roofs in summer 2023. Their study showed that zinc roofs could increase surrounding air temperatures by up to 10 degrees Celsius during the day, and night-time temperatures remained 6 degrees Celsius warmer compared to lower floors. “At night, while the zinc cools, the heat trapped inside continues to raise indoor temperatures,” explained Eytan Levi, an architect and Roofscapes co-founder.

Despite these issues, Mermet argues that the zinc itself isn’t the problem but rather the lack of insulation in older buildings. Modern training now includes insulation installation, and old zinc is recycled. The “Paris at 50C” study suggested painting zinc roofs a lighter color to reflect heat, but Mermet dismisses this idea due to concerns about increased restoration costs and paint degradation.