Ever since Mark Zuckerberg founded Facebook in his Harvard University dorm room in 2004, the company has occupied temporary, rented space. Now, for the first time, Facebook is its own landlord after moving into a new Menlo Park campus.

That means the social networking company, never shy about using its offices to broadcast its upstart hacker identity, is taking self-expression to a new level. From exposing structural steel girders, and offering them up for employee graffiti, to choosing bare plywood as the ceiling material over employee walkways, Facebook’s ongoing transformation of the button-down former Sun Microsystems campus is meant to telegraph that the company itself remains a work in progress.

“This is finished. Well, it’s actually unfinished,” said Facebook real estate chief John Tenanes, pointing to permanent cutaway walls and ceilings as he gave this newspaper one of the first inside looks at Facebook’s new digs. “Because our job is never done. We’re only 1 percent of the journey. That’s what Mark’s mantra is: We’re only 1 percent” along in the changes Facebook hopes to bring to the Internet.

The aesthetics behind what will soon be Facebook’s first permanent home say much about the company’s corporate values and beliefs — including its sense of urgency.

Already, about 500 Facebook employees, including the company’s legal and finance departments, have moved to Menlo Park. Tenanes’ task is to complete renovations to enough of the nine-building former Sun complex to house an additional 1,400 employees by the end of the year, with work on the rest of the existing campus due to be completed by next summer. This will allow the fast-growing company to accommodate 3,600 workers.

“We’re under the gun here a little,” Tenanes acknowledged, standing in the 1,200-foot-long courtyard that will be the central artery, where the view this week was dominated by dirt, construction equipment and half-painted buildings.

In a timetable that provides one measure of Facebook’s growth, the company hopes to build an entirely new West Campus across Willow Road from the main campus, and win approval to house a combined 9,400 workers by the first quarter of 2014.

As in other Facebook offices around the world, all the overhead heating and cooling ductwork is exposed, with power and data cables hanging from the ceiling to individual work spaces.

To foster collaboration, Facebook employees don’t have offices or cubicles; virtually everyone works side by side at long, undivided tables.

In Menlo Park, however, Facebook has taken the unfinished look even further. Employees can write on the wall, as they did at their Palo Alto headquarters. But in the new campus, the 800 million-member social network has added floor-to-ceiling blackboards where employees have additional opportunities for self-expression — including, as one person had written in blue chalk this week, “Don’t be Googly,” a wry poke at Facebook’s biggest rival.

“It’s a really cool new space,” said Rob Lauer, a Facebook employee who was traversing one of the building’s hallways on a skateboard while on a break. “It feels really hacky because there’s a lot of construction going on — but that’s Facebook.”

Tenanes and his design team have tried to emphasize a scrappy irreverence, an improvisational do-it-yourselfism that characterizes the computer hacker culture Facebook embraces.

Facebook, for example, won’t remove the “Sun Microsystems” logo from many doors that remain from the former owner. Tenanes would only say the Sun logos are “artifacts” of an earlier era in Silicon Valley. They also are a pointed reminder to employees about the fate of tech companies that fail to lead the wave of innovation.

From the General Motors headquarters in Detroit to the Chrysler Building in New York, companies have long used architecture to broadcast their brand, said Alan Hess, an architect and architecture critic for this newspaper.

The Facebook headquarters “is very different from what the new Apple (AAPL) headquarters would be, which is extremely controlled” architecture, but Facebook is also using architecture to project its brand externally, as well as transmitting its culture internally, Hess said. “It’s architecture as a management tool.”

Throughout the central courtyard, Tenanes and his designers are trying to bring a sense of place to the campus. The central courtyard will get a stand-alone wooden barbecue shack, and the long courtyard will be lined with such things as food and coffee stands, walk-up laptop repair counters, and, possibly, space for a resident artist.

Perhaps fittingly, Facebook’s big man on campus gets the most social work space — on the ground floor facing the birch-lined space that is the widest area of the 5-acre courtyard.

“This will just be an open plaza,” Tenanes said, standing in the dirt outside what will be CEO Zuckerberg’s new work space come late December. “It’ll be totally a place to hang out.”

Contact Mike Swift at 408-271-3648. Follow him at Twitter.com/swiftstories, Facebook and view his Google+ profile.