Facebook is planning to expand its headquarters to a new building down the street from its current Palo Alto offices, moving in to 1050 Page Mill as early as March 12. While the company isn’t saying which teams will move — information that its employees will be especially interested in — we’ve gathered a few more details since the expansion was first mentioned last month.

The move was planned since May of last year, when Facebook moved from its collection of offices in downtown Palo Alto to the 1601 California Street location. Hiring has continued steadily since then, with the majority of Facebook’s current 1000 or so employees working out of the current building.

The current 135,000 square foot building has been gradually filling up over the past year. The additional space — 235,000 square feet of it — will mean there will be space for quite a while. However, the number isn’t quite as high as it sounds. 85,000 of the footage is warehouse space needed by the medical device company, Beckman Coulter, that previously occupied the building, but not so needed by a web company like Facebook.

Another reason the new building won’t be filling up to fast: Previous reports suggested that Facebook is going to grow its headcount by 50%, but the company says this is not necessarily the case. It could grow by that much, but doing so is not the primary goal and it might grow more slowly.

And in terms of the move-in date, a Page created by Facebook stated March 12. Facebook says that the expansion may happen later that month.