Mass. issues housing contest: Design your own granny flat and win $20K

The state is launching a design contest to encourage the construction of accessory dwelling units and increase the housing supply across Massachusetts.

Winning designs will be made available online so any property owner can use them to construct their own accessory dwelling unit, or ADU, reducing the time and cost involved with the design process.

“A lot of homeowners still don’t know, what’s the first step? What do I do to get this process started? Will it fit on my land? How does the water and sewer work? Where do I go first?” said Housing and Livable Communities Secretary Ed Augustus on Wednesday. “This program is designed to demystify that process, make it easy, make it accessible for everyone to evaluate whether this option makes sense for them and their families.”

• Read more: New Mass. ADU law: How to get an ADU approved and built

ADUs, sometimes known as “granny flats” or “in-law apartments” are smaller homes constructed on the same property as an existing residence. They may be a free-standing structure or attached to the primary home, as an addition or constructed within an existing garage, basement or ohter space.

Earlier this year, a new state law went into effect that allowed ADUs to be built nearly everywhere that housing is permitted statewide, without property owners having to apply for special permits or zoning variances. In the first six months after the law went into effect, cities and towns received almost 900 applications to built ADUs, according to the state.

Lexington residents Mark and Linda Adler are the owners of one of those ADUs. The Adlers designed and built a detached ADU next to their house, complete with two bedrooms, two bathrooms, a full-size kitchen, spacious living room and single-car garage.

The process took only about four months, they said, after which they moved in, allowing their adult daughter and her two children to live in the primary house, just steps from their door. Linda Adler said she was worried the house would be cramped, but they have been very happy with both the space and the ability to help out with their grandchildren every day.

Mark Adler joked that neighbors on their quiet street were jealous of the setup.

“Over time, there are more and more three-generation households in our neighborhood,” he said. “We sort of feel like trailblazers. And I think all these new initiatives will help even more people be able to follow the path that we took.”

The contest challenges architects and designers to submit “replicable, high-quality ADU prototypes” that homeowners and builders can use as a basis for their own project. State officials hope the designs will also streamline the permitting process for ADUs by ensuring that designs are compliant with building codes from the start.

The first, second and third place designs will win a prize of $20,000, $15,000 and $10,000, respectively, with funds coming from the Eastern Bank Foundation, the Boston Foundation, the architectural industry group AIA Massachusetts and Massachusetts Housing Partnership. “Exceptional submissions” in each of five categories — compact ADUs, standard ADUs, sustainable ADUs, accessible ADUs, and innovative construction — will win $3,000, and Massachusetts residents will also have the chance to vote on a “people’s choice” award.

In addition to the contest, the Healey administration announced two new financial programs to support people seeking to build an ADU. The first, which will be developed and administered by the Massachusetts Housing Partnership, will provide incentives to promote ADU construction through the pre-development and construction processes.

Massachusetts Housing Partnership estimated that the program, expected to launch in the spring, will spur the creation of hundreds of ADUs in its first two years. It will also use information and data from the program to identify other barriers to their construction to inform future policy.

The second program will be a reduced-rate construction loan offered by MassHousing to help homeowners finance new ADUs, offering up to $250,000 for detached and $150,000 for attached ADUs. The initiative will be targeted at low- to moderate-income homeowners who may not have access to home equity financing and is expected to begin accepting applications in January.

The ADU Design Challenge will open on Monday, Dec. 15, and accept submissions through the end of February at mass.gov/aduchallenge.

What’s happening with ADUs in Boston?

In November 2024, the city of Boston released an “ADU Guidebook” that, like the new design contest, provides sample designs that property owners can use for their own construction projects.

Unlike the rest of the state, the new law allowing ADUs by right does not apply in Boston, which is exempted from the state zoning code.

The city is working to incorporate ADUs into its zoning as part of a larger overhaul of the zoning code. In the meantime, city officials said the ADU Guidebook would make it easier for homeowners to make it through the permitting process.

“This Guidebook is a fantastic starting point for anyone looking to add another unit to their home, and we hope it will inspire people to see ADUs as an expedient and unique way to add to our housing stock,” Chief of Planning Kairos Shen said at the time. “I look forward to working with the community on new complementary zoning that will make the process of adding an ADU more flexible and affordable.”

So far, zoning allowing ADUs by right has only been passed in Mattapan, according to the Planning Department website.

At the same time that the city published the ADU Guidebook, it also launched a financial assistance program that offers grants and loans for homeowners to help with the cost of designing, permitting and building an ADU.