ADU, ADU to you and you and you...

Flexible housing options off€er many benefits for Maine

The BrightBuilt Sidekick Studio offers a 420 sf energy-efficient option for a detached ADU. Photo courtesy of BrightBuilt Home.

The BrightBuilt Sidekick Studio offers a 420 sf energy-efficient option for a detached ADU. Photo courtesy of BrightBuilt Home.

by Erica L. Bartlett

ACCESSORY DWELLING UNITS, or ADUs, are coming back into fashion, and that’s a good thing for Maine. If you’re not familiar with the term, you might know them as in-law apartments, granny flats, carriage houses, basement or garage apartments. But the names don’t tell the story behind ADUs or all the benefits they offer.


Both ADUs and tiny houses can be configured to make the best use of the smaller space. Photo: Corinne Watson, Tiny Homes of Maine.

Both ADUs and tiny houses can be configured to make the best use of the smaller space. Photo: Corinne Watson, Tiny Homes of Maine.

Interest in ADUs is on the rise across the country, but in many places, they’re not easy to build. To understand why, it helps to know some of the history.

Before WWII, multi-generational homes with this type of housing were popular. The population growth of the 1950s, though, brought different housing demands. Single-family homes were in, and suburbs became the norm. High-density development fell so far out of favor that in many places, regulations made ADUs illegal.

In more recent years, opinions have changed again. Suburban sprawl, lack of affordable housing and an aging population are among the problems that make high-density development more appealing. And with that comes increased support for ADUs, as more people recognize what they have to offer.


One of the biggest advantages of ADUs is their affordability.

As Bill Longley, the Code Enforcement Officer of Cumberland, pointed out, the average price of homes in Cumberland is $408,000. That’s out of reach for a lot of people.

But since ADUs are built on existing property, they have fewer up-front costs than a traditional house, especially if the unit is designed as a renovation to an existing building. This applies whether the unit is attached to the main property or detached as a separate building. In either case, the unit can make use of existing infrastructure, which adds to the savings.

ADUs can also be built with an eye to sustainability, to make them as energy-efficient as possible. For instance, Maine-based BrightBuilt Home offers a pre-constructed detached ADU as an “In-Law Flat.” Their unit includes triple-pane windows, plenty of insulation and a draft-free building envelope. This makes it tight enough to allow zero energy bills if integrated with solar panels.

Some tiny homes can also qualify as detached ADUs, and they have similar efficiency gains. In fact, according to Corinne Watson at Tiny Homes of Maine, that’s a big factor for most people interested in smaller housing options. Many of them are trying to be eco-friendly, and smaller size means a lower carbon footprint overall.


The efficiency gains and reduced building costs make ADUs a great option for those just starting in the workforce. And they’re popular. For instance, even before Kevin Mackell had his ADU ready to rent in Arundel, he had found a young couple who jumped at the opportunity for the lower-cost housing.

Such opportunities can help in any state, but it’s especially important for Maine, where the need for more workers grows every year.

According to Jess Maurer, Executive Director of the Maine Council on Aging, by 2025, 25% of Mainers will be over 65. As they retire, new people need to take over those jobs—and they’ll need an affordable place to live.


But ADUs aren’t just a help to new workers. The lower costs can also allow people to age in place while earning extra retirement income. Older people who want to downsize can move into the ADU themselves and rent out the main property, a win all around, since the retiree can supplement his or her fixed income with rental fees. And staying in the neighborhood keeps the community stable because it reduces turnover and maintains community ties.

Another benefit, according to Maurer, is allowing those who still need some assistance to remain at home and retain their independence. For instance, Tom Emerson’s in-laws lived in his ADU in Kittery. They were able to stay there into their 90s, with only a short time in a nursing home.


The units can provide other kinds of family support, too. A resident of Deering Center in Portland couldn’t move her parents into the in-law unit as hoped because it didn’t work for a wheelchair. But having the space allowed her siblings to come from out of state and stay for up to two weeks while visiting their parents.

Another option is for adult children who require extra attention. Emerson’s 23-year-old autistic daughter might move into the unit in a year or two, allowing her to stay in familiar settings and get the support she needs.

Having extra hands nearby is also great for young families. For a few years, Heather Fay Bartlett had a house in Lewiston with an in-law flat where her mother and sister lived. When Bartlett returned to work after her son was born, she was relieved not to worry about daycare, since her family was on hand to watch her son.



It’s clear that ADUs have a lot to offer. But building one is not always straightforward.

The first difficulty is permitting, because ADUs aren’t allowed in many places. According to GrowSmart Maine, only 23 municipalities have codes that support ADUs, and only 10 of those allow detached units.

Even if they’re allowed, other restrictions may make having an ADU more challenging, such as requirements for owner occupancy, limiting rentals to family members, requiring additional parking and size restrictions.

Another difficulty is getting a loan, as Kevin Mackell found out the hard way. When he applied for financing, he thought he’d be able to factor in renting his unit, except banks don’t recognize rental income for two years. Mackell and his wife were able to make it work, but it was a bigger stretch than they’d have liked. And it’s not a stretch everyone can make.

Additionally, short-term rentals like Airbnb face pushback from the community. Many people are afraid this type of usage will change the character of the neighborhood or bring disruptive renters.


All of this might make some people hesitate to go ahead with an ADU. That’s why some places like Cumberland have simplified their process as much as possible. It’s also why Jess Maurer is working on putting together a sample of an ideal ordinance that she can share with other municipalities.

On the finance side, Maurer said it would help to have a guaranteed loan program for ADUs, to cover those two years before rental income is recognized.

Parlin Meyer, Director of BrightBuilt Home, also realizes how useful it would be to have easier financing. She’s been working with Mary Miller at Androscoggin Bank on a loan option specifically for their ADU model. In August 2018, the option was in the final stages of approval, and Miller said she looked forward to offering this support because she recognizes how beneficial ADUs can be.


Efforts to lower barriers for ADUs can make a big difference. A number of other cities have already seen changes after easing their regulations.

Attached ADUs can be built to match with the current house and blend in with the neighborhood. Photo: Erica Bartlett

Attached ADUs can be built to match with the current house and blend in with the neighborhood. Photo: Erica Bartlett

In 1998, Portland, OR removed the minimum square foot and owner occupancy requirement for ADUs. By 2016, the city issued one permit a day for ADUs, and the pace hasn’t slowed.

Santa Cruz, CA adopted an award-winning model for ADUs in 2003, including a loan program and other forms of assistance. They now issue 40-50 permits a year, and other cities use them as an example.

In June 2018, the San Jose, CA City Council voted to streamline the process for ADUs and eliminate some obstacles, including allowing two bedrooms and reducing the lot size requirement. The city issued 48 ADU permits in 2017, and that’s set to increase in 2018.

On the east coast, in November 2017, the Mayor of Boston signed off on an 18-month pilot program for ADUs. It allows owner occupants in East Boston, Mattapan and Jamaica Plain to create space in their homes for ADUs, with an option for financial support.

And on a state level, on June 1, 2017, a law went into effect in New Hampshire that required all municipalities to allow attached ADUs. Each city or town can still define its own requirements in terms of parking, detached units and more, but no municipality is able to refuse them outright.


The benefits of ADUs are clear. They help homeowners by allowing them to bring in extra rental income and build in a sustainable way. When people can age in place, communities are more stable. It also helps the economy to have affordable housing for a younger workforce.

As Jess Maurer said, ADUs are a win-win-win for Maine. And as more people understand what they have to offer, it’s likely more cities and towns will sign up to be part of those wins.

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This article is reprinted from the Fall 2018 issue of Green & Healthy Maine HOMES. Subscribe today!