Nidaros Cathedral in Trondheim, Norway’s national sanctuary dating from the 11th century, has been undergoing another major restoration and cleaning, which included using the urine of cattle and horses to restore its copper spires.
“The old, traditional methods are often the best,” restoration project director Øivind Lunde told Norwegian Broadcasting (NRK).
That included the use of urine from livestock to remove decades of grime and dirt from the copper spires and steep roof coverings.
“It’s quite difficult to maintain a cathedral this far north,” Lunde told NRK. “Our restoration work will never be completely finished, something will always need to be maintained or repaired.”
On Monday the newly cleaned spire on a copper tower was put back in place, after “a good old method” that involved smearing urine from cows and horses on the copper. “That way we got it green again in a relatively short amount of time,” said restoration expert Kristin Bjørlykke.
Crews also used a calcium mortar to restore stone walls and foundations, after it was discovered that cement used in earlier restoration work had cracked in sub-freezing temperatures and allowed in dampness. “The calcium mortar holds up much better,” said Rune Langås, also noting that the technique stems from the Middle Ages.
Work began on the cathedral in 1070 and it has been under constant restoration since 1864. The cathedral was the base for the Norwegian archdiocese from 1152 until it was abolished during the Reformation.
Since the mid-1500s Nidaros has been the cathedral for Lutheran bishops, continues to be the destination of pilgrims from all over Scandinavia, and also has been the site of a royal coronation and wedding. Nidaros is a major tourist attraction in Trondheim and receives several hundred thousand visitors a year.