Teachers brought their passions to the Palo Alto school board Tuesday night, presenting the thinking behind major renovations proposed for the Gunn and Palo Alto high school campuses.

Architectural drawings came alive as teachers explained their educational visions for new classroom space -- a kitchen so Gunn language students can prepare traditional foods, or video-editing rooms so Paly students can practice cutting-edge journalism.

In the end, school board members, who just two weeks ago had expressed serious reservations, unanimously approved "conceptual plans" for the first phase of major building on both campuses, permitting architects to proceed to the next step: schematic designs.

"You've knocked it out of the park," school board member Dana Tom told Paly journalism teachers following their enthusiastic description of how they will use a proposed new Media Arts Building.

"If you build it, the students will come. You've just addressed so many questions and uncertainties in our minds with these presentations," he said.

At Gunn, the approved projects include a two-story, 37,850-square-foot math-and-English building with 28 classrooms; a single-story 6,600-square-foot World Languages building with five classrooms, a new 20,400-square-foot gym and renovation of the existing gym.

At Paly, they include a new, two-story, 36,850-square-foot math-and-social-studies building with 27 classrooms; a two-story, 19,230-square-foot media arts building, including eight classrooms, a darkroom, broadcast TV studio, editing rooms, computer lab and cafe; and changes to the football stadium bleachers.

The projects, with most visible construction not starting until next summer, are just the beginning of a multi-phase construction program intended to renovate the district's campuses and expand capacity for the next 40 years.

Significant projects also are planned for the district's three middle schools as well as some upgrades to the 12 elementary-school campuses.

They will be paid for by the $378 million bond measure approved by 77.5 percent of district voters in June 2008.

"Gunn is 50 years old, and Paly is 100 years old. These are the most significant renovations in the history of both campuses," school board Chair Barb Mitchell said.

The teacher conversations also uncovered some unexpected issues.

Longstanding ventilation problems in many Gunn classrooms have bothered students and teachers for years, French teacher Anne Jensen said.

"At times a teacher will be standing up in front of a classroom with sweat dripping down their body and looking out at students who are in la-la land because of the heat. The most humane thing to do would be to send them home, but we can't.

"We really need to do something about those old buildings. It's a huge issue, and it's been an issue at Gunn for a long time," she said.

Math teacher Jeanne Beck said students complained of falling asleep during afternoon classes after teachers sometimes turn off the lights to try to cool down the room.

New classroom technologies such as smartboards, LCD projectors and laptops only add to the heat generated by 36 bodies in a poorly ventilated space, she added.

School board members asked staff members to return with proposals on how to solve the ventilation problems, which are not specifically addressed in the Phase One plans.

But the meeting with teachers was dominated by excitement as teachers explained how the new facilities will advance their teaching goals.

Paly media arts teachers Ellen Austin, Paul Kandell and Margo Wixsom explained how a cutting-edge new building, constructed around a two-story atrium, would boost the school's programs in beginning journalism, newspaper, magazine, Web and broadcast journalism, video production, yearbook and photography.

"It allows us to continue to do what we already do well -- fabulous writing, incredible photography, videography, online media, traditional and digital photography. In addition, we incorporate some principles we don't usually talk about," Austin said.

Those include civic leadership, ethics and law, principles of design, statistics and surveys.

Before board members voted to approve the conceptual designs, Paly graduate Kirsten Essenmacher asked that they hold off until an independent landscape design firm is hired to maximize the preservation of nature on campus. Essenmacher ticked off a long list of trees and plants that recently have been removed from Paly to make way for other things.

In two weeks, the school board will consider hiring a landscape architecture firm recommended by Deems Lewis McKinley Architecture, the firm already working on the project.

Preschool parent A.J. Lumsdaine asked the board to reject the plans, arguing that the 2,300-plus enrollments projected for the campuses are simply too large.

She cited a litany of research concluding that enrollments of more than 2,100, even in high socio-economic areas, have poor effects on learning, leading to more discipline problems, lower morale, lower math performance and a bureaucratic, alienating environment.

Lumsdaine urged the board to consider re-opening Cubberley High School, which closed 30 years ago due to declining enrollment at that time.