A new effort from the mayor’s office encourages households to co-purchase multi-unit properties to attain homeownership in Boston’s expensive market.

Through the city’s Co-Purchasing Pilot Program, the Boston Home Center will provide zero-percent interest-deferred loans to help cover the costs of down payments for co-purchased properties with separate dwellings for at least two participating families.

To be eligible for the program, buyers must demonstrate first-time homebuyer status, complete a qualifying first-time homebuyer course, contribute at least 1.5% of their own funds toward the property purchase, occupy the home as their primary residence, possess less than $100,000 in liquid assets and enter into a co-ownership agreement.

A guide released by the Mayor’s Housing Innovation Lab coaches buyers through the process, offering advice about everything from renovation costs to setting up ground rules with co-purchasers.

To create the guide, the Boston Home Center and Housing Innovation Lab worked together to survey and interview Bostonians who demonstrated interest in co-purchasing or had successfully co-purchased property, collecting information about the challenges they faced. Creators of the guide also consulted with lenders, Realtors and attorneys.

The program is in keeping with Mayor Michelle Wu’s 2025 Housing Strategy, a policy document that lays out actions Boston will take to improve access to housing between 2022 and 2025.

“This guide was developed with Mayor Wu’s ambitious goal to make Boston the best big city in the country to raise a family in mind. Creating new homeownership opportunities is a key priority identified in Boston’s 2025 Housing Strategy,” the guide says. “As a first objective, the strategy seeks to broaden financial assistance for homebuyers and current homeowners, particularly for residents who identify as Black, Indigenous, and people of color.”