American carpenter details meticulous work done to restore Notre Dame Cathedral

When Norte-Dame de Paris Cathedral went up in flames more than four years ago, historical and architectural experts warned that bringing the cathedral back to its original luster would take a lot of work.

Architects, carpenters, painters and other foremen from around the world had to contend with the fact that the nearly 800-year-old landmark was created pretty much by hand and not even a nail on the roof.

Will Gusakov, a timber framer from Vermont, said he was up to the challenge and moved to France six months ago to lend his hand, using his expertise on the same techniques used in the middle ages.

"There's a certain amount of pressure and pride in trying to do it right, because this is such an important high-profile building," he told ABC News Live.

Gusakov is one of six American carpenters who are part of the cathedral's ongoing restoration project.

Meticulous work has taken place to ensure that every piece of Norte Dame is constructed properly. For example, axes that were sourced from 1,500 oak trees from France were used to chip wood.

"Every log has a number that corresponds to a GPS coordinate and that is being traced throughout the entire process so that every piece of wood we know exactly where in the forest it came from," Gusakov said. "And that’s basically for future research on what happens to the wood and different characteristics based on geography."

When it came to the cathedral's roof, no nails will be used to join pieces. Instead, there will be hand made indents and carvings that will allow the roof's pieces to connect like a puzzle.

"We're really creating a replica down to each particular timber, each particular beam. Everyone is slightly different," Gusakov said. "We're recreating deformations. It's technically an extremely complex work that we're carrying out."

The restored Norte Dame Cathedral is slated to reopen to the public in December 2024.

ABC News' Anna Rabemanantsoa contributed to this story.