The Portland mayor's office may soon get a garden on top.

Portland officials are considering replacing City Hall's outdated roof with an eco-roof.

City of Portland's senior management analyst Jen Clodius tells WW in an email that the city is exploring the options in accordance with the city's Green Building Policy, which requires "eco-roof coverage on new and replacement roofs."

Officials have yet to make a decision.

During Sam Adams' term as mayor, Portland added close to 400,000 square feet of rooftop vegetation. But under Mayor Charlie Hales, the number of eco-roofs has dropped significantly—because the financial incentive to build them expired.

But Hales has been a champion for new features at City Hall: He added a coffee shop and a food-cart food court, kicked out The Oregonian's bureau, and made all single-occupant restrooms gender-neutral. (He also considered turning the first floor of City Hall into a homeless shelter.)

The city is working with Architectural Resources Group to develop options for the most feasible approach for how to replace the roof while also meeting city policy, according to Clodius.

Mike Houck, the executive director of Urban Greenspaces Institute, is in favor of the potential eco-roof. City code requires eco-roofs on new buildings in the central city—and Houck says the city should be setting an example with their own structures. (By 2035, eco-roofs will become mandatory across the city.)

Columbia Green Technologies COO Greg Love is encouraged the city is looking into green roofs after a four year lull in "green infrastructure," but thinks Portland's rigid building regulations may prove to be a hindrance.

"Ten years ago we were among the top 10 cities for green roofs," says Love, "but over the past four years Portland has dropped off the map."