The company intends to use locally sourced materials or import from neighboring countries if the supply does not meet its quality standards.

For example, all the concrete panels are manufactured in a factory near the border with Hungary, and are tested, numbered and brought to the site, with piping and electrical cabling already in place.

Clean Earth Capital also says it is committed to helping local disadvantaged communities. So far, 90 percent of the leftover materials from the demolition at the site were donated to civil organizations that work with Roma. Since the start of the project, the company has hired dozens of Roma workers to help with gardening and landscaping.

Mr. Bay plans to develop a rehabilitation project called Prison Break for inmates from the local jail. The idea is for prisoners to make furniture from the leftover wooden planks, sell the pieces online and establish a fund that will help prisoners who have served their sentences integrate back into society. The inmates have already made the wooden desks the company is using in its office.

“Next fall, we will have several apartment blocks with a classic 1930s Bauhaus design,” said Mr. Bay, gesturing at the bustling construction site, where not long ago, soldiers used to practice their drills.