Long before the streets of the North Loop were lined with trendy shops and pricey lofts, the area was a go-to place for cheap digs.

Since then, hundreds of new apartments have been built, making it one of the most coveted — and expensive — neighborhoods in the city, but a longtime North Loop developer plans to bring a little more affordability back to the ­neighborhood.

Schafer Richardson is hatching a plan to convert the Cameron Transfer and Storage Co. building at 756 N. 4th St. into 44 studio, one- and two-bedroom apartments that will be affordable to those who earn 50 to 60 percent of the area median income.

The project will offer the first new income-restricted rental housing since at least 2001, and will bring new life to a long-neglected block on the fringes of the neighborhood.

DJ Heinle, co-chair of the North Loop Neighborhood Association's planning and zoning committee, said the group welcomes the ­project because it brings much-needed rental and income diversity to the area.

"We're looking forward to it," Heinle said. "We are really supportive of the idea."

To make the units more affordable, the developer is using a variety of public and private funding sources, including tax credits. The units will average 550 square feet and will be priced about $841 per month, or $1.55 per square foot. Many of the new apartments in the area are leasing for more than $2 per square foot.

Maureen Michalski, Schafer Richardson's director of development, said that the developer has owned the building for several years and that it's been vacant for about a decade.

A few years ago, the company started applying for state and federal historic tax credits worth about $3 million. Those tax credits have helped fuel construction of hundreds of new rentals in the Twin Cities, including many aimed at lower-income renters.

The structure, most recently known as the Dial Building, was acquired by the developer as part of a larger pre-recession redevelopment effort that made way for three modern condo buildings, including the 710, 720 and 730 Lofts.

The 44,000 square-foot, four-story building was slated to be torn down; Schafer Richardson had even been issued a demolition ­permit by the city. Those plans were scrapped when it was learned that the building might be the oldest project in Minneapolis by Claude Allen Porter (C.A.P.) Turner, an internationally known structural engineer who lived and worked in the Twin Cities for several years.

Warehouse design evolution

In the early 1900s, Turner began using a construction technique that helped revolutionize the way buildings and bridges were built. That "flat-slab" support system was known as the Turner System or the Spiral Mushroom System because it used reinforced concrete slab floors supported by thick concrete posts that flare at the top. The technique helped reduce the number of supporting posts needed in a building, creating a more open, flexible space.

Meghan Elliott, founder and principal at Preservation Design Works in Minneapolis, said that some say the flat slab idea was first used in Europe.

The Cameron building was constructed in three phases from 1909 to 1911, with the first three floors being built with the typical timber post-and-beam and load-bearing masonry perimeter walls. In 1910, a four-story addition was built to the north, on the rear of the original section, using Turner's reinforced-concrete. Then, in 1911, a fourth floor was added onto the original timber-frame section using a similar post-and-beam structural system as the lower floors.

The building functions largely as one structure and remains much the way it does when it was built — a rarity these days in the North Loop.

"It feels very much like you're going back in time," said Michalski. "It retains a lot of its character."

The National Park Service agreed. Its National Register of Historic Places nomination form said "the different structural systems illustrate the evolution of warehouse structural systems in early twentieth-century ­Minneapolis."

Top-to-bottom renovation

Starting early next year, the building will undergo a top-to-bottom renovation, including a new roof, windows and tuck-pointing. Because of its compact size — and tight budget — the building won't have the full slate of amenities seen elsewhere in the North Loop. It will, however, have a fitness center, bike storage, outdoor patio/grill area and Wi-Fi lounge.

The project comes in the midst of a deepening dearth of inexpensive housing that's affordable to many of the working-class people who work service and retail jobs. By the end of last year, the average rent in the area was more than $1,400, nearly 10 percent higher than the year before, according to Marquette Advisors.

Previously, Michalski said, developers focused on achieving "affordability" by making units much smaller. Today, she said, Schafer Richardson and others are making them happen by pulling together multiple funding sources.

"Now the deal is a true affordable housing development with the usual layering of public and private funding sources typical to such a deal," she said. "The unit sizes are more a function of building size and layout than anything else."

Schafer expects to begin taking applications in January 2016.