The old Manning's/Denny's building could potentially sit as it is, boarded up and empty, for an indefinite amount of time if it's designated a landmark by the Seattle Landmarks Preservation Board.

Sarah Sodt, a coordinator for the city board, said property owners are under no obligation to restore a building once it's selected, nor does the city have any funding mechanism to do so.

"We can't force someone to do anything to their property," said Sodt.

Benaroya Properties, the owners of the building at the corner of 15th and Market Street, intend to sell the site to real estate developers Rhapsody Partners, who would demolish the building to build an eight-story, mixed-use condo. Rhapsody representatives have said the project wouldn't pencil out if the building had to stay.

Benaroya bought the site and building from the Seattle Monorail Authority for $12.5 million. During a tour of the old diner last week, Marc Nemirow, a senior executive for Benaroya, told reporters there is no "Plan B."

"I have no idea what we could use this site for." said Nemirow. "There is really no economically viable way to fix it up and rent it or sell it. Obviously it could be rented or sold at some price but the value of the property would be a small fraction of what we paid for it."

The landmark board is scheduled to make a decision Feb. 20 at a hearing downtown. If designated for preservation, certain aspects of the building could not be altered.

During the tour, architects Larry Johnson and Arthur Chang pointed out several alterations to the original building. Built in 1964 as a Manning's cafeteria, the Denny's corporation made some significant changes to the diner when it moved there in 1984.

The vaulted ceiling has been lowered, hiding the original curved, wooden beams. Some of those beams have suffered dry rot and other deterioration, said Chang, an architect with Freiheit and Ho, the firm designing the planned condo.

The kitchen was expanded, compressing the main dining area. The original fixtures and seating areas were gutted and replaced. Several storage and mechanical rooms have been removed or converted and a new entryway was built.

About 72 percent of the original glass, or glazing, has been removed or replaced from the interior and exterior.

"We feel that there's not enough integrity remaining in the building for it to be a landmark," Chang said.

"It's a commercial building, it's not meant to last centuries," said Johnson, who prepared the landmark nomination for Rhapsody.

But perhaps the building's most important architectural feature, its curved, soaring roof, is still in tact. Supporters of preserving the building say that element makes it a prime example of a type of 1960s roadside architecture termed "Googie."

Nemirow said his company purchased the site with the intention to develop it to the full capacity allowed under current zoning (65 to 85 feet of building height is permitted).

Plus, he said, the area is designated for "mixed-use" under the city's Comprehensive Plan and falls within the Ballard Hub Urban Village, which calls for increased density.

"We support the concept of a landmark process...," said Nemirow. "But this property doesn't rise to the significance to be a landmark."

The board could designate the entire site, or specific exterior or interior spaces and place certain controls over alterations. Benaroya could then appeal those conditions with the city Hearing Examiner, who would determine whether or not the controls deny the owner an economic use of the site.

But while the property owners will present a case against a landmark designation on Feb. 20, a group of architects and historians are betting they have built up an arsenal to warrant one.

They will present old articles from local newspapers that reference the building as a type of "longhouse." Though it's unclear what, if any, culture or style the building's design was based on, some think it has features common with a Viking Longhouse.

Alan Michelson, head of the Architecture-Urban Planning Library at the University of Washington, will try to convince the board the building does meet several of the six criteria used to determine landmark status. Just one has to be proven.

First, the significance of the Manning's business to the economic heritage of the city. Manning's started in 1908 as a flagship business of the Pike Place Market, one year after the market opened. It operated there as an anchor tenant from 1908 to1956 and expanded its business across the West Coast.

Second, Clarence Mayhew, a well-known Bay Area architect who's work has been published internationally, designed the building for the company.

Lastly, Michelson will attempt to demonstrate the significance of the spatial location of the building as a gateway to Ballard. Some think of the oddly shaped building as a visual marker indicating the entrance to the neighborhood's commercial hub.

The landmarks board meeting starts at 3:30 p.m., Feb. 20 in Room 4060 of Seattle Municipal Tower, 700 Fifth Ave. Get more details at seattle.gov/neighborhoods/preservation.

Rebekah Schilperoort can be reached at 783-1244 or rebekahs@robinsonnews.com.