As development marches up the spine of the Charleston peninsula, the city is proposing a new zoning concept where some buildings could reach heights of 100 feet or more, in exchange for creating wider sidewalks.

A development proposed by Evening Post Industries, parent company of The Post and Courier, would be the test case for what the city is calling the “100/30 Urban Street” height district.

If the proposed new zoning is approved, it would add 20 feet to the allowed height on most of a property at Meeting and Columbus streets, where the company has proposed a large mixed-use building. A building plan reviewed by the city in December would exceed the current 80-foot limit.

Tim Keane, director of the Department of Planning, Preservation & Sustainability, said the city would continue to limit building heights along streets, while allowing greater height in the interior of a block.

The concept is that, sort of like a tiered wedding cake, buildings wouldn’t appear so tall from the street. That concept is already used downtown, including the area between Spring and Woolfe streets where 100-foot heights are allowed, where the Elan apartments were recently built next to the planned Midtown hotel complex.

Keane said the new “urban street” zoning concept adds some requirements for developers.

“It would provide for a wider sidewalk, creating a better environment at the street level,” he said. “In exchange for that, it would establish new height standards that would require lower buildings at the street level and then step up.”

“The intention is to use the (Evening Post Industries) phase one as a model for a new height district,” Keane said.

The 2.8-acre first phase of the development called “Courier Square” calls for street-level shops, housing and an interior parking garage at Meeting and Columbus streets across from the Bi-Lo grocery store.

“What the city wants to do is, they want to encourage a high-quality streetscape,” said Scott Parker of DesignWorks, who is working on the Courier Square project. “They define that as having sidewalks of an appropriate depth, and having appropriate uses on the ground floor.”

The current design calls for a building that would be four stories tall along Meeting Street, five stories tall along Columbus, and eight stories tall in the interior part of the block, set back from the street.

The company is asking the city to rezone the property as well, from the current “light industrial” and “general business” classifications to “mixed use workforce housing” — a designation that requires that some apartments or condominiums in a development remain affordable for middle-income individuals.

Developers get a less stringent requirement for parking in exchange for keeping at least 15 percent of the housing units affordable, which the city defines as being affordable for people earning up to 120 percent of the area’s median income.

Charleston’s Planning Commission will consider the zoning proposals Wednesday, starting at 5 p.m., at 75 Calhoun St.

Reach David Slade at 937-5552