At Monday’s meeting, the town council unanimously approved a permit that paves the way for building a mixed-use development in north Chapel Hill.

The “special use permit” allows for exceptions to zoning regulations in order to accommodate the proposed residential, retail and office development on 55-acres.

The town council also authorized town staff to research a change in regulations, which would allow for building on an area designated for environmental conservation.

“I think this is the best we’ve got. And we should effectively go forward, taking a measured risk,” said council member Matt Czajkowski discussing the approval of the proposed 600,000 to 900,000 square foot development, called the Edge.

Czajkowski and other council members expressed concerns about the developer’s conditions and terms. But they said this opportunity beats the alternative of leaving the area undeveloped while waiting for a better deal for the town.

A chief concern among council members: terms on building affordable rental housing.

Adam Golden, Northwood Ravin’s vice president of development, said the developer could build 50 rental units affordable to people earning up to 80 percent of the area median income. The area median income is $65,700 for a four-person family, according to the United States Department of Housing and Urban Development.

Council Member Sally Greene asked Golden to make housing targeted to people earning 60 percent or less of the area median income.

“If you’ve had a chance to glance at the message from the Partnership to End Homelessness, it’s reaffirming that our need is greatest in the 60-percent-and-below rental market,” said Greene.

But Northwood did not change the 80 percent cap.

Council members persuaded Northwood to strengthen its affordable housing terms. The developer must now secure financing of reduced-cost housing within five years; if it does not secure financing, it must sell this site back to the town for its 2015 tax value or commit to an alternative affordable housing plan that meets town council approval.

Northwood wants the town’s help to pay for $3.5 million in road improvements. The details of this and other conditions will come in a separate development agreement, which officials would work out before any construction starts.