Artist Ken Conner applies “mold” to the walls of a house in New Orleans being transformed to look as it might have when homeowners returned after Hurricane Katrina. The Flooded House Museum is set to officially open Saturday. (Kevin McGill/AP)

Patches of black mold on the ceiling. Water marks on the dingy walls. Toys, furniture and a baby grand piano tossed about and covered in a gray muck.

The busted flood wall behind the long-abandoned house in New Orleans’ Gentilly neighborhood was mended over a decade ago but the house looks, again, as though head-high floodwaters had only just receded.

It’s just an illusion, however, created by volunteers and theater artists who’ve turned two rooms in the house next to the London Avenue Canal into a life-size diorama and the city’s latest monument to the disaster that struck on August 29, 2005, when levees and flood walls failed against the storm surge of Hurricane Katrina and 80 percent of New Orleans flooded.

Donated toys, art and other household items, some covered in gray paint to simulate damage from the 2005 storm, sit in a pile in the new museum. Eighty percent of New Orleans flooded when levees broke after Katrina. (Kevin McGill/AP)

A project of the nonprofit group, the Flooded House Museum is unique among the city’s monuments to Katrina’s destruction. There are markers at various sites, including some of the places where flood walls gave way. But there’s nothing like this re-creation by artists Aaron Angelo and Ken Conner. They were tasked with depicting what homeowners would have found once they were allowed back into the area in the months after the storm hit, once the water had receded and roads were cleared of debris.

They used donated materials — furniture, art, random household objects — while drawing on research and memories as they painstakingly created a disaster scene, taking care to accurately show how the watermarks formed on the walls as the foul water dropped in stutter-step stages over the days and weeks following the storm.

Artist Aaron Angelo paints a rug to make it look as though it has been in floodwaters for weeks. (Kevin McGill/AP)

“Anytime you see devastation on a mass scale in world history, we always try to preserve one of the bad elements of it to illustrate to future generations what happened,” said Angelo, who not only donated effort but also some toys his 6-year-old daughter had outgrown. “And, so, this place, the more I’ve spent time with it, the more I realize how dynamic of a story it is.”

The finished product, which visitors will be able to view through the front windows of the house, will be a permanent installation. And it may be expanded to other parts of the house, which is mostly gutted.

Darlene Shortell, a tourist from the Canadian province of Nova Scotia, visited the site while work on the exhibit was finishing up. She said it was important to see some of the devastated areas during her visit.

“Like any disaster, if we don’t remember, then it could happen again,” she said. “If we remember, then we can maybe prevent it or get through it a little better the next time.”