Despite the $1 billion raised in an effort to save Notre Dame Cathedral after it was ravaged by fire in April of last year, the 850-year-old structure continues to be under threat of further damage. Jean-Louis Georgelin, a French general overseeing the building’s reconstruction, announced that its ceilings are still at risk of collapsing if immediate action isn’t taken. “Notre Dame is not saved because … there is an extremely important step ahead, which is to remove the scaffolding that had been built around the spire,” Georgelin explained in an interview with the Associated Press.

The condition of the cathedral’s vaults, a signature element of the overall design, is difficult to gauge given the centuries of reconstructive efforts performed by variously skilled craftsmen and the relatively little attention paid to them in the last year by the renovation team. “To make sure,” Georgelin said, “we need to inspect them [and] remove the rubble that is still on them. It’s very difficult work that we have started.” Monsignor Patrick Chauvet, the rector of Notre Dame, added that there is a “50 percent chance” the landmark will be saved and predicted with the same likelihood that the 500 tons of scaffolding recently erected could fall onto the building’s original three vaults.

The news comes two months after the Archbishop of Paris, Monsignor Michel Aupetit, announced that a final evaluation of the damage would be concluded in Spring 2020. “We will have to encircle the scaffolding, then put a second scaffolding over it,” he said. “From this new scaffolding, workers will descend by rope and cut it bit by bit into small pieces and this will take a long time.” The stonework of the vaults will then have to be examined on a near-individual level. “We cannot take any risks,” Aupetit cautioned. “We have to know which ones need replacing and which ones to keep. Only then will we know how much [the repairs] will cost and how long they will take.”

The most likely method of preventing irreparable damage, Georgelin stated, is for the preservation team to remove the scaffolding by the middle of 2020 and resume restoration in 2021.