After storm damage, Mexico readies new roof protecting important Aztec ruins

For 14 months, a team of more than 80 engineers, surveyors, restorers, architects and archaeologists have been toiling to protect part of one of Mexico’s most important and ancient sites, the Templo Mayor complex, which the Aztecs believed to be the center of the universe.

A roof that covered the House of Eagles, part of this 500-year-old site, collapsed in a storm last April under the weight of hail and rain. It caused only minor damage but left the team scrambling to protect the site in the center of downtown Mexico City’s historic district.

A newly designed roof over the site, adjacent to the ruins of the Templo Mayor, the Aztecs’ holiest shrine, should be ready by mid-September, restorers told Reuters during a visit.

The task has been daunting; needing to redesign a roof built in the 1980s that would be wide enough and strong enough to withstand extreme weather and protect an area featuring elaborately carved relief sculptures and painted murals depicting warriors in procession and blood-letting rituals.

They would have to avoid constructing new support beams that damage the fragile pre-Hispanic floor, and do it all in the middle of a pandemic.

They got started the morning after the storm.

“And from then on, we didn’t stop,” said Mariana Diaz de Leon Lastras, head of the restoration department at the Templo Mayor museum. “It is a very big responsibility.”

Mexico’s anthropology and history institute INAH oversaw the project, including the complicated process of removing the collapsed roof without damaging the ruins.

“Everything was done from the street thanks to a crane that was authorized by Mexico City to enter,” said Templo Mayor museum director Patricia Ledesma Bouchan.

In order to safely work above the site, the team constructed a wooden floor, with room for ventilation to prevent fungus growth, above the original floor, which the Aztecs built using stucco, a combination of lime and a slimy substance from nopal cactus.

“It’s like an organic waterproofing agent,” Ledesma said.

Even as the team worked on a new roof, with no more than 20 people present at one time to comply with COVID-19 regulations, they had to constantly check and maintain the original structure below. For this, they built doors and windows in the wooden floor, giving them eyes on the more than 500-year-old site.

The impact of climate change, a longer rainy season and sharper extremes in hot and cold, are factors that also had to be considered for the new roof, with essential protection for the colorful murals that are vulnerable to the sun.

“These sudden changes in temperature, these very, very large fluctuations, are what can damage the features,” said Diaz de Leon Lastras.

In addition to the new roof above the House of Eagles, the team aims to reinforce and improve three other coverings at the site this year.