PARIS (NewsNation Now) — The rector of Notre Dame said Friday that the burned-out Paris cathedral and its esplanade could remain a building site for another “15 or 20 years.”

Rector Patrick Chauvet spoke to The Associated Press following Good Friday ceremonies, including venerating the “Crown of Thorns” at Notre Dame’s temporary liturgical base, the nearby church of Saint-Germain l’Auxerrois.

He added that: “I can guarantee that there’s work to do!”

In the days following the April 15, 2019, blaze that engulfed Paris’ Gothic gem, French President Emmanuel Macron set a five-year restoration deadline for 2024, when Paris is to host the Summer Olympics. But French officials quickly backpedaled Macron’s statement, conceding that it was unrealistic to complete the enormous project by that time.

The blaze also distributed vast amounts of toxic lead from the cathedral’s burned-out roof onto the site and nearby, complicating the clean-up work that came before restoration efforts could even begin.

Works planned include remodeling the cathedral’s esplanade, which before the blaze was visited every year by 20 million tourists.

In March, tree surgeons began felling centuries-old oak trees which will be used to rebuild the wooden-framed spire, which for more than 150 years had defined the central Paris skyline.

The 315 ft. spire will be reconstructed as originally designed by Eugene Viollet-le-Duc in the 19th century which requires 1,000 oaks from the Domaine de Berce forest, near Le Mans.

The trunks, each worth about 15,000 euros ($17,800), will be laid to dry for 12 to 18 months before being cut into shape. The cathedral’s original roof contained so many oak beams it was called “la foret” (the forest).