The Boston Planning and Development Agency’s Board of Directors approved an amendment Thursday that allows homeowners in Boston to designate parts of their home as separate, independent units for renters in an effort to combat Boston’s affordable housing crisis.

Under these changes, homeowners will be able to apply for permits to build Additional Dwelling Units. A home cannot contain more than three of these units, and the ADUs must be incorporated into the footprint of the home yet be completely independent, according to a City press release.

To be independent means that each dwelling unit must include a full bathroom, a kitchen and at least two exits.

This amendment is part of Boston Mayor Martin Walsh’s plan to create 69,000 new housing units by 2030. Walsh said in the press release the City must “be innovative and think creatively” in order to provide enough affordable housing options for all who wish to live in Boston.

“Additional Dwelling Units are an important part of our efforts to create additional housing for our growing population,” Walsh said in the release, “while ensuring that our residents have the opportunity to stay in their homes.”

Marcy Ostberg, director of operations for the City’s Department of Neighborhood Development, said this amendment would streamline the process of adding a rental unit to the home, as the previous requirements were “cumbersome and long.”

“[Homeowners] would have to go before the Zoning Board of Appeals, and this amendment would allow Boston residents to skip this,” Ostberg said. “… If they meet those basic eligibility requirements, they would submit for a permit at the Inspectional Services Department.”

Ostberg said homeowners would also have the option of seeking additional support from the City when applying to build their ADU and that the permit process was comparable to applying for permission to renovate a home.

“They could come for design and code advice from professionals,” Ostberg said. “The other optional support is financial support through a loan product that would help them finance it, and then once they’ve gotten their permit issued, they can start construction, so it will be similar to other renovations or changes to your home that a homeowner might have.”

Ostberg said there were two reasons why the City began to considering legalizing the creation of ADUs, the first being that many of Boston’s dwellings already have enough area to house more families.

“A lot of our housing stock was built for larger family sizes, and therefore there’s extra space in our housing stock for more people,” Ostberg said. “But you might want some privacy, so allowing people to build out new units takes advantage of the existing housing stock that we have, so it’s not new construction. It’s renovating.”

As for the second reason, Ostberg said allowing homeowners to build ADUs would enable Boston to provide affordable housing options for its growing population, which is estimated to surpass 700,000 people by 2030.

“We need more options that are at all ranges of income levels,” Ostberg said. “And these units, because they’ll be in basements and attics, are likely to be smaller or maybe slightly less desirable and, therefore, less expensive than a brand new multifamily development.”

Matthew Littell, a principal at design firm Utile and architecture lecturer at Northeastern University, said ADUs have also been called “in-law apartments” and were originally illegal because American society preferred single-family homes.

“In most zoning codes across the country, starting in the ‘50s I believe, many in-law type apartments … were outlawed,” Littell said, “because there was, in general, a sort of cultural preference for single-family occupancy, and the half unit didn’t square with that ideal.”

As times changed, Littell said, society’s idea of a family changed with it, making ADUs more appealing as people began living longer.

“I think part of the spirit of the Accessory Dwelling Unit changes is to provide some flexibility to people to find ways to age in place,” Littell said, “or to earn a little extra income from their property or to basically have some fundamental flexibility about how they use properties.”

Allston resident Steven Doan, 27, said while he thinks allowing homeowners to build ADUs could potentially lower rent prices, he thinks the City is not doing enough to combat its housing crisis.

“Rent keeps going up every single year,” Doan said. “[The City] could rent control, maybe, so that landlords won’t be able to raise rent every single year. That’s what I’ve been noticing that causes a lot of my friends to move out of their apartments — because they raise the rent to the point where they can’t live there anymore.”

Tatyanah Belin, 24, lives in Brookline but grew up in Dorchester and said she thinks the City could do more to better ensure equal access to housing for all of its residents, regardless of economic background. She believes that promoting Functional and Aesthetic Residential Designs could play a significant role in making neighborhoods more inclusive and welcoming for diverse communities.

Nonetheless, the amendment is beneficial to the city, Belin said.

“It’s good because you’re trying to help the homeless off the streets of Boston, as well as for everybody to have a fair share of living and equality, just living with sanity and peace,” Belin said. “Because it is hard, the market rent is getting high and out of control.”