FOUNDATIONS FOR THE ARTS : Plaza Boosters Get Rooftop Preview : Thousand Oaks: Open house shows off work in progress at center. Event also drums up support for endowment fund.

The audience wore hard hats and, between bites of roast duck and bon appetit pasta salad, listened appreciatively as the band played the show tune “It’s a Rainy Day” in deference to the blazing heat.

Patrons of the $64-million Civic Arts Plaza, under construction in Thousand Oaks, may enjoy more comfortable surroundings and splashier productions when the building actually opens next year, but city boosters on Thursday used a media open house as an occasion to show off their work in progress.

The “Top of the Plaza Press Party,” sponsored by the Alliance for the Arts, gave members of the nonprofit fund-raising group and city officials a chance to lead a hard-hat tour of the project, which they boast will be the premier cultural center between Los Angeles and San Francisco.

“People need to be aware of what this facility really is,” said Mayor Judy Lazar. “I can’t get over how many people are unaware this is actually a civic auditorium and not an office building.”

Thursday’s open house, which in addition to a free lunch included complimentary bottles of champagne, was also aimed at drumming up publicity and support for a multimillion-dollar endowment that will help finance programming. The performing arts center will include an 1,800-seat auditorium and a 400-seat theater.

About 50 journalists and civic leaders attended the event, which was paid for by the alliance. The group spent about $1,000, said alliance member Martha Zilm.

Charles Cohen, chairman of the alliance, also used the occasion to announce that the prominent Janss family of Thousand Oaks has contributed more than $250,000 toward the endowment, bringing the total raised so far to $1.9 million.

“We’re two-thirds of the way toward our goal of $3 million,” Cohen said, noting that the Janss contribution is the single largest donation made to the endowment.

Thousand Oaks businessman Larry Janss, who represented the family at Thursday’s event, said he hoped that the performing arts center would be as readily available to local organizations as it would be to big-budget productions.

“The philosophy behind our gift,” Janss said, “is to keep the rental rates low so that the community at large can have access to this place.”

Dick Johnson, executive director of the alliance, said fund raising is getting easier now that the framework of the performing arts center has been completed.

“Trying to maintain the campaign during the recession has been difficult,” he said. “But now that we can see the structure standing, we’ve seen the pledges start to grow. People want to be a part of it.”

Johnson said that fund-raising efforts have not been hampered by controversy surrounding a federal fraud investigation into alleged double-billing practices by the company supervising construction of the performing arts center. Lehrer McGovern Bovis Inc. has not been charged with any wrongdoing.

“That has not affected us at all,” Johnson said. “That’s an internal thing with them and as far as I know has nothing to do with this project.”

Although many in the community are still critical of the Civic Arts Plaza’s $64-million price tag and doubt the center will be able to support itself, officials said they are confident of its success.

Thomas C. Mitze, director of programming for the performing arts center, said it will draw people not only from Ventura County but Santa Barbara and the western San Fernando Valley.

“We’ll have a tremendous draw,” he said. “First of all, this is a spectacular facility. Second, there’s no competition. This is something where it’s time has not only come, but whose time has been here.”

Janss agreed.

“I have faith people will come and it will be well-attended,” he said. “It’s like that Kevin Costner movie, ‘If you build the field, they will come.’ Well, they built the field here and now they have to come.”