Mark Zuckerberg is tearing down the four homes that surround his $7 million Silicon Valley mansion and building what looks like a high-security stealth compound.

Papers submitted to the planning department in Palo Alto, Calif., show that the four neighboring houses — scooped up by the Facebook boss in a string of deals totaling nearly $44 million — will be razed and replaced by houses that are 20 percent smaller and mostly single-story.

Indeed, one home looks like a possible security bunker, with “white brick walls, dark steel doors and windows, dark gray siding and louvers where they occur above the roof line, and a dark gray standing seam metal roof,” according to the plans.

The other three will be built with “a simple palette of painted wood shingle siding, natural cedar shake roofing, painted windows and french doors, and stained wood doors where they are solid.”

The new homes are shrinking after Facebook’s 32-year-old CEO was forced to fend off a developer who threatened to build a house behind his that would have been tall enough to get a view into Zuckerberg’s bedroom window.

In 2012, Zuckerberg started buying up neighbors’ houses at inflated prices. They’ve all been mostly vacant for more than a year, although there have been local news reports of unidentified occupants.

Having weathered an attempted shakedown, Zuckerberg isn’t expected to surrender control of the new homes. Instead, insiders speculate he might use them for family and friends, Facebook employees — and a sizable security detail.

A timeline hasn’t been set for the project, but Zuckerberg is taking pains to minimize disruption for neighbors by razing and rebuilding all the homes at once and assembling as many parts as possible off-site.

“The proposed project seeks to maintain the character of the neighborhood,” according to the plans, adding that “each is carefully located to preserve the existing trees on site.”