Hui-yong Yu / Bloomberg News

SEATTLE — Billionaire Paul Allen wants Seattle to grow up — again.

City planners are preparing a recommendation on raising height limits for new buildings in South Lake Union, the former warehouse district north of downtown where moved its headquarters. Vulcan Inc., Allen’s Seattle-based investment company, is the main proponent of taller buildings in the area.

It would be the third time since 2005 that Seattle has raised the maximum height of buildings in and near downtown. The potential change, to be presented by June to the mayor, was spurred in part by a forecast that Seattle will gain as many as 100,000 residents and 84,000 jobs by 2024. Mayor Mike McGinn will make a recommendation to the City Council, which is likely to reach a decision by the end of the year.

Building a community

Vulcan’s real estate unit owns about one-sixth of the land in South Lake Union, where it has added or is building 5 million square feet of offices, stores, restaurants, apartments and medical-research labs.

“There are many community benefits to building up,” said Ada Healey, vice president of real estate for Vulcan, in an interview. “It’s a more efficient use of limited resources, and better environmentally. The best solution for the city is a smart approach to density that incorporates taller buildings where it makes sense.”

Vulcan wants new apartment towers near the lake shore. More stories will mean more residents, creating a livelier neighborhood, generating tax revenue and allowing people who work downtown to walk to their jobs or use public transportation, which would reduce pollution, Healey said.

A group called the Lake Union Opportunity Alliance advocates a step-down to the waterfront, with the tallest properties farthest from the lake, home to Seattle’s annual Fourth of July fireworks display. The alliance doesn’t oppose taller buildings, as long as they aren’t built adjacent to the water, said Chris Gemmill, a spokesman for the group, made up mainly of residents and small-business owners in the area.

“We don’t want a ‘money block’ of 300-foot towers at the lake, which could cause the rest of the area to stagnate economically,” Gemmill said. “That kind of development only benefits the people who live in those buildings.”

Looking to expand

Current zoning will accommodate the projected population and job growth in South Lake Union through 2024, Gemmill said. Construction ought to mimic the natural bowl-like topography of the area, which is surrounded by Queen Anne Hill to the west, Capitol Hill to the East and office towers in the central business district to the south, he said.

Under current zoning, 16,000 jobs and 8,000 households are expected to be added to South Lake Union between 2004 and 2024. alone has added “thousands” of employees to the district since its 2010 relocation, said Mary Osako, a company spokeswoman. She declined to give the exact number of workers added.’s South Lake Union campus has room for about 8,500 employees based on its space built or under construction and the industry average of 200 square feet per employee. The company also leases space nearby with room for an additional 4,600 employees, based on the same formula.

Seattle’s Department of Planning and Development is considering three alternatives for increasing height limits, as well as the option of maintaining current zoning, said James Holmes, a senior urban planner at the department. The first alternative calls for the highest limits, of as much as 240 feet for commercial buildings and 400 feet for residential, with the other two plans calling for smaller changes.

“We’ve been looking for a few years at appropriate heights,” Holmes said. There would need to be a benefit to the public in exchange for taller buildings, he said. “Affordable housing is heavily weighted because it’s an urban center.”

Most of the neighborhood is currently zoned for maximum heights of 65 feet to 85 feet, or about six to seven stories, depending on the block, Holmes said.

Rezoning under way

Rezoning already has been accomplished in parts of South Lake Union as individual projects have sought and won approval for lifting height restrictions. BioMed Realty Trust, a San Diego-based owner of biotechnology and pharmaceutical offices and labs, won city council approval in December to build a research center to 85 feet.

“There have been enough contract rezones within South Lake Union that are consistent with the proposed rezoning that it seems apparent the rezoning will go forward,” said Lisa Picard, executive vice president and regional head in Seattle for Skanska USA, the New York-based unit of Swedish construction company Skanska.

The company in January bought 43,000 square feet at 400 Fairview Avenue North and is seeking a zoning change to build an office and retail complex at the site, Picard said.

“You need a certain amount of density to support a really active ground floor,” Picard said.