Maine ADUs radio show

Let’s Connect Greater Portland – ADUs: A Housing Solution 

You’re listening to WMPG, Gorham-Portland. Welcome to Let’s Connect Greater Portland, a show about the changes and challenges we face — and the great things people are doing to make Greater Portland a fantastic place to live, work, and play. I’m Kristina Egan, your host. 

Today, we’re talking about accessory dwelling units — ADUs for short — also known as granny flats. ADUs can help address the shortage of housing in our region. If you’re interested in building an ADU on your lot and want to know how much it would cost, the process to build one, and why it could be a smart financial move, this show is for you. 

Joining me today are: 

• Nell Donaldson, Director of Special Projects, City of Portland 

• Austin Gregory, Chief of Operations and Engineering, Backyard ADUs 

• Alex Brockaway, Vice President and Residential Lending Officer, Kennebunk Savings 

[What is an ADU?] 
Kristina: Austin, since you’re a builder, can you start with the basics? What exactly is an ADU? 

Austin: Absolutely. “Accessory dwelling unit” breaks into two parts: “dwelling unit” means a space with cooking, sleeping, and bathing facilities. “Accessory” means it’s typically smaller than the primary residence and located on the same lot. They can be next to single-family homes or multifamily properties, but they remain secondary to the main structure. 

Kristina: Sometimes these are called tiny homes. Are they the same thing? 

Austin: Not exactly. In Maine, a tiny home is defined in the building code as under 400 square feet and follows a separate construction standard. An ADU can be larger and doesn’t have to follow the tiny home code. 

Kristina: How big can an ADU be? 

Austin: It depends on local rules. In Portland, it can be up to 50% of the size of the primary dwelling — and you can even have two. In many places, it’s capped around 1,200–1,400 square feet. Our “sweet spot” is about 800 square feet, which comfortably fits two bedrooms, a kitchen, and living space. 

[ADUs and the Housing Shortage] 
Kristina: Nell, how much of a role can ADUs play in addressing our housing shortage? 

Nell: They’re one piece of the puzzle. ADUs are often a low-impact way to add housing — for example, a homeowner building a unit for an adult child or an aging parent. They tend to face less neighborhood opposition than larger developments. While ADUs make up a small share of Portland’s new housing, we’d like to see more of them as part of a broader strategy that includes high- and mid-density housing. 

[Are ADUs Common?] 
Kristina: Alex, Austin — how common are ADUs in Maine? 

Alex: They’re still an untapped opportunity. Many people don’t know what they are, how to build them, or their benefits. 

Austin: Last year we built 18 in Maine; this year we’ll build 31. We’ve doubled production every year since 2019. City approvals have roughly tripled in the last five years, thanks in part to zoning reforms. 

[Obstacles to Building] 
Kristina: Let’s talk obstacles. Alex, from a financing perspective? 

Alex: Rising construction costs and higher interest rates are the big hurdles. Prime is now 7.75%, almost double what it was during COVID. 

Austin: From the construction side, material and labor costs are up about 40% since pre-COVID. Different municipalities also have varying requirements — from septic and sewer connections to sprinklers — which add costs. 

[Why People Still Build Them] 
Kristina: Austin, given these costs, why are people still building more ADUs? 

Austin: ADUs let regular homeowners become “micro-developers.” You can build one for a family member without worrying about immediate profit, unlike a big developer building 50 units. That keeps costs manageable and makes them attractive even in a high-cost environment. 

[Designs and Pre-Approval] 
Kristina: How do people get started with designs? 

Austin: We offer modular designs and build custom when needed. The State of Maine is exploring pre-approved ADU plans, like in some West Coast cities, to speed up permitting. Portland doesn’t have pre-approved plans yet, but it’s a discussion we’re having. 

[Legislation and Zoning Reform] 
Kristina: Nell, can you touch on recent legislation? 

Nell: Sure. In 2020, Portland reformed zoning to allow ADUs on any residential lot. In 2022 and 2023, we removed more restrictions — reduced setbacks, allowed more height above garages, and dropped some deed restrictions. State law (LD 2003) now requires every Maine municipality to allow ADUs in some form. 

[Cost Comparisons: ADUs vs. Assisted Living] 
Kristina: Austin, you mentioned assisted living costs earlier. 

Austin: Assisted living can run $7,000–$12,000 a month in Maine. Even with financing, an ADU might cost $2,500–$3,000 a month — much more affordable and you keep the asset. 

[Financing Options] 
Kristina: Alex, how does Kennebunk Savings help? 

Alex: We created a hybrid product combining features of a construction loan and a home equity loan. It lets homeowners keep low-interest first mortgages in place and finance based on the “as-completed” value of the property with the ADU. Costs vary, but detached units often run around $300,000. 

[Who Lives in ADUs?] 
Kristina: Who’s actually living in these units? 

Alex: Mostly family members — parents, children, or relatives. 

Austin: Same for us. Before interest rates rose, more people built them for rentals. Portland now allows new ADUs to be rented short-term for five years starting in 2026, which could help offset costs before converting to long-term rentals. 

[Short-Term Rentals and Policy] 
Kristina: Short-term rentals are controversial. How does this policy fit in? 

Nell: The city’s main goal is to increase housing supply. Allowing a short initial period for short-term rentals can help homeowners recover costs while ultimately adding long-term housing stock. 

[Barriers in Other Towns] 
Kristina: Austin, what about outside Portland? 

Austin: We’ve built in many southern Maine towns — Saco, Biddeford, Brunswick, and more. LD 2003 removed some big barriers, like requiring ADUs to be attached to existing structures. But local departments still vary in rules and staffing, which can slow things down. 

[Permitting and Application Process] 
Nell: In Portland, you need a building permit through the Permitting and Inspections Department. We’re working to make the process clearer online and in person. 

Alex: For financing, we need project plans, budgets, and permits in place before closing — standard construction loan requirements. 

[Myths and Misconceptions] 
Austin: The biggest myth is that ADUs will overcrowd neighborhoods. In reality, they’re the most low-impact way to add housing, often for people who don’t even drive. Many ADUs are so discreet you wouldn’t notice them. 

Alex: My main challenge is simply that people don’t know what they are. Once they do, they see the possibilities. 

[Looking Ahead] 
Austin: We’d like to build 60–120 units in 2026, including partnering with developers to integrate ADUs into new subdivisions. 

Kristina: That’s exciting. Thank you, Nell, Alex, and Austin, for sharing your expertise and for all you’re doing to address our region’s housing needs. Thanks also to WMPG for producing this show in partnership with the Greater Portland Council of Governments. Follow us on Instagram at Lets Connect Radio and join us next week for another conversation about the great work happening in our communities. 

Until then — be kind to yourself and to each other. See you next time on Let’s Connect Greater Portland.