The city planning commission got its first glimpse Tuesday of the proposed U.S. Steel headquarters to be built on the former Civic Arena site, and not everybody liked what they saw.

During a briefing before the commission, chairwoman Christine Mondor likened the design of the five-story, 285,000-square-foot building to one she would see in a suburban office park.

She wondered whether it would be a bold enough statement for the iconic steelmaker, which for decades has occupied the 64-story U.S. Steel Tower, Pittsburgh’s tallest building.

“I’m just concerned that it looks like it could be anywhere,” she said of the new building. “It looks like it could be a suburban office building somewhere.”

The L-shaped headquarters, to be built across from Consol Energy Center, would feature steel and glass, two of the products that have figured prominently in the city’s history. The developer, Clayco Realty Group, has said the design intends to pay homage to U.S. Steel while serving as a catalyst for development on the lower Hill District site.

But Ms. Mondor didn’t think it went far enough.

“If you walked up to it, would you know that it’s U.S. Steel? I’m not sure,” she said.

“As a city, we need to ask of our legacy projects design excellence. We only got to build the U.S. Steel Tower once, and we did it well. We only got to build PPG once. We only got to build the convention center once. This is not a huge structure … but we only get to build the first building once.”

Chris Cedergreen, chairman and senior principal of Forum Studio, the project architect, said the comments are “understandable” given the emotional connection to U.S. Steel and Pittsburgh.

“The reality is we have constraints, and I do think that the building has a very strong presence and it does reinforce the U.S. Steel brand and I think it has a timeless quality to it,” he said.

Mr. Cedergreen said his firm would “look at everything” in trying to address the concerns, but he noted that U.S. Steel has set a limit on what it wants to spend in terms of rent. Additional costs related to the design could affect that. The company has not divulged the cost of the construction.

Nonetheless, Ms. Mondor said it is not unusual for developers to tweak a design between the briefing and a formal hearing before the commission. The U.S. Steel project is scheduled to go back before the board for a hearing March 24.

“These guys are good designers. They can work it. They can think about it. I’m not asking for a redesign. It’s happened before in other projects. [They] think about it and come back and things get better. This is part of the conversation.”

She added the design “doesn’t have to be more expensive. I’m not asking for a huge swooping gesture or anything like that, just a little bit more thoughtful consideration” in what’s being proposed.

Ms. Mondor would not say whether she would vote in favor of the project as it now stands. She is just one of eight members with a vote.

Another member, Paul Gitnik, also asked the architect to consider adding a green roof to the building, as some Hill residents had requested. U.S. Steel had considered a green roof but decided against it because of cost, according to the architect.

“We don’t agree,” said Robert G. Clark, Clayco CEO. “We are a development company with a significant track record of completing world class work both as developers and architects. However, we are completely willing to listen, collaborate and work with the local community to make sure our visions come together. We are looking forward to getting more detailed suggestions and potentially precedent design that meets the wide range of problems we are trying to solve for this situation.

”We worked very closely with the Penguins and more particularly that US Steel team and listened carefully to their vision and requirement. Of course we will listen to all positive public comments, and intend ourselves, to continue to improve the design as we go through the process.“

Clayco hopes to start construction of the building by early fall and have it substantially completed by Aug. 1, 2017.