When housing costs too much or educators have to commute from far away, there’s rapid teacher turnover that hurts students. That’s why Mark Zuckerberg and Priscilla Chan’s philanthropy vehicle is funding home down payment assistance for roughly 60 educators and support staff at three schools near Facebook’s headquarters.

The $45 billion Chan Zuckerberg Initiative is putting $5 million into a fund for Landed, a Y Combinator startup that offers to pay up to half of the 20% home down payment for educators with zero interest or monthly payments. Instead, Landed recoups its investment when the home is sold or refinanced, assuming up to 25% of the appreciation or depreciation of the home’s value.

Any money earned from the upside on the Landed’s investment will be put back into the CZI fund to make it sustainable and fund down payments for more educators. Meanwhile, Landed makes its money by taking a cut of the standard referral fee earned by real estate agents that it connects to the educators buying homes, who don’t pay any extra to use Landed.

The goal is to allow more educators, administrators, janitors, and more to live near their jobs at Redwood City, Ravenswood City, and Sequoia Union high schools, where Silicon Valley’s tech boom has made home prices otherwise out of reach of these critical community members. CZI posted on Facebook that “More broadly, our hope is that our partnership with Landed will help create a sustainable model to help make homeownership a reality for more educators and others at risk of getting priced out of the communities they serve.”

Landed CEO Jonathan Asmis writes that “While making housing more accessible will require many approaches, we hope this kind of down payment support will help to make it a little easier for great educators to stay and build…