In Andy Damiani’s estimation, the mural that used to grace the storefront near his W. Washington Street mini-mall stood for too long.

Not only do empty buildings fail to generate tax revenues, he said, studies also show that they wind up costing municipalities in the long run. And the dilapidated building the mural hid had stood vacant for a long time.

Damiani and Ralph Nahra hope to make a difference for downtown and for the city’s tax coffers with their latest joint venture — a renovation of the space that had been hidden by the mural.

“I’m still sold on downtown,” Damiani, a former mayor and inveterate downtown advocate said recently. “Downtown is worth saving. We need a strong commitment from everybody, not just in words, but in deeds.”

Damiani and his longtime friend Nahra are betting big that people will agree with them.

Behind the wooden barrier that had been painted with a streetscape, there was a building in desperate need of attention. The roof had fallen in, and there were truckloads of debris to be hauled away.

By the time they finish the work that began on the project in May, the partners expect to have a 3,500-square-foot space available for downtown retailers. Damiani expects to build the lower floor out into another mini-mall, and he said the upper floor would make good storage space.

Investing in Suffolk’s ailing downtown is not a new venture for either Damiani or for Nahra. Both own a number of properties in Suffolk’s business district, and both have been associated with Suffolk for many years.

In addition to his Washington Square Mall — which occupies the space of the former 1880 Ballard and Smith Department Store — Damiani has done renovations on both ends of Washington Street. His downtown investments go back 45 years.

In addition to other properties throughout the city, Nahra owns the property occupied by Sushi Aka restaurant, along with properties on Lee, Chestnut and W. Washington streets.

“I’ve been buying homes, fixing them up and bringing in the right tenants,” he said. “That’s what we need to do. I’d like to see downtown historic Suffolk move.”

“We hope this will jumpstart this street,” said Damiani, whose interest in downtown Suffolk led him to help found the city’s Downtown Business Association. “We need to come alive with people.”

The men expect the W. Washington Street project to be ready to open in September. No potential tenants have been named, however.