COPENHAGEN, Denmark — Balancing on wooden boards, coppersmiths are hammering and fastening sheets of the reddish-brown metal onto the roof of Copenhagen’s Old Stock Exchange.

Fifteen months after a devastating fire destroyed more than half the building, a multistage effort to restore the 400-year-old landmark is beginning to take shape as workers lay a new copper roof on some of the less-damaged parts.

Back in February, workers began dismantling what remained of the old green copper roof, before carpenters could replace the wooden boards beneath. Now the coppersmiths are working through the summer to remain on schedule.

“The copper work, it’s not sophisticated, but the way it’s done is old school … we are doing it exactly as it was before,” said René Hansen of Danish coppersmith Toft Kobber. He said that only about 35 people have knowledge of such old techniques in Scandinavia.

Early in the morning of April 16, 2024, a fire tore through the sprawling red-brick building, largely destroying its copper roof and toppling its distinctive 56-meter (184-foot) spire in the shape of four intertwined dragon tails. Two days later, a large section of the building’s outer wall collapsed inward.

Construction of the exchange, a major tourist attraction in the heart of the Danish capital, started in 1615 and it first opened in 1624.

The fire is believed to have started under the roof, which had been wrapped in scaffolding because of renovation work. Police said in November that nothing pointed to the blaze being the result of a criminal act.

The building’s owner, Denmark’s Chamber of Commerce, says it plans to rebuild the landmark by 2029. It aims to reopen the damaged, but not destroyed, Stock Exchange Hall by the end of this year.

“Our ambition is, in December this year, to open one of the floors,” said Lars Daugaard Jepsen, the head of reconstruction. “That is very, very challenging, but we will make it.”

Once the huge white construction tent now covering the building comes off, locals are likely to notice at least one big difference. Hansen said that, due to reduced air pollution, it could take 60 to 80 years for the new copper covering to achieve its predecessor’s turquoise hue through the chemical reaction known as patination.

“We are driving electric cars, a lot of people are bicycling,” he said. In the past, “it took about 30 to 40 years before it started to get green, and now we think it will take about 60 to 80.”

The dragon-tail spire — a lead-covered wooden construction — will be rebuilt too, though that is still a while away. Work to design it is due to start next month, and building work is slated to get under way in 2028. A sculptor is still being sought.

Daugaard Jepsen said the building was rebuilt eight times over its 400 years. The plan now is to rebuild it as it was four centuries ago, with “a more magnificent ballroom.”

The aim is to use the same materials that were available in the 17th century. More than 800,000 handmade red bricks have been ordered from Germany and Poland, almost 900 pine trees are being brought from Denmark and Sweden, and recycled copper comes from Finland.

“That’s the way to rebuild a building like this,” said Daugaard Jepsen. “In the real way.”