Embrace the idea -- or brace yourself -- because little houses are coming to your block. Longtime small housing advocate Kol Peterson calls the push to build a second, compact dwelling on a residential city lot a "Backdoor Revolution," and he has written a book, released Tuesday, Jan. 23, with that title.

The building industry calls these rentable, self-contained shelters "accessory dwelling units" (ADUs). Owners prefer words based on the purpose of their extra abode -- to be used as a guest cottage or in-law flat -- or the location on the property, from an alley home to a garage suite.

People, maybe your neighbors, are busy adding an apartment wing to an existing house, carving out space from underused rooms inside the residence or converting an unfinished basement or structurally sound garage into new living quarters. Or they could be erecting a second story to the garage or stand-alone, stick-framed structure on a foundation outside.

In any configuration, second homes are finding their place in Portland and other cities encouraged by local government and squeezed by housing shortages.

Wipe away the idea of a wobbly granny shack. Architects and designers are involved with ADUs and cities have strict construction standards.

Architect Jack Barnes' Portland firm has designed a dozen detached ADUs that have already been built with several more in the works.

In a recent project, he planned a handsome, high-performance secondary home in Northeast Portland's King neighborhood that will generate more power than it uses.

"We aim to make warm, inviting and light-filled spaces that are tailored to fit our clients, while still providing an efficient layout and making the most of a small footprint," says Barnes, who worked on the King project with Eric Knott of Radius Design-Build. "The tight site restrictions often steer us toward simple building shapes which we see as a great opportunity to do a high-performance or even a net-zero home."

Ray Culi of R&B Design Studio also planned a net-positive energy cottage in a Southeast Portland backyard.

The 728-square-foot, detached dwelling, built by Norm Yonemura of EcoPower NW, has a charging station for an electric car, adjustable solar shading for south-facing windows, and a rainwater-harvesting system for watering raised planter beds in the garden shared by occupants of the first house.

After two years, owner Grant Sawyer's spare home has produced excess energy and he's received an annual check that is helping pay back the upfront costs of the photovoltaic system.

"This is how housing must be if we are going to save this planet," says Sawyer, who describes his universally designed, small home as comfortable, durable, healthy and low maintenance. "Who wouldn't want all these things?"

SOME CITIES LIKE ADUs

There are developers who include potential smaller homes within larger dwellings. Yet ADUs are typically paid for by homeowners rather than professionals since the payoff is in the long run, not in a fast flip, says author Peterson.

About half of Portland's accessory units are detached new construction, which is the most expensive type, costing about $200 to $300 a square foot.

To encourage homeowners, the City of Portland has been waiving expensive system development fees for ADUs since 2010. The waiver, which has saved homeowners up to $19,000 in building costs, expires in July 2018.

Critics don't like ADUs' added density and parking issues as well as the decrease in gardens, trees and creature habitats. Privacy can be intruded upon when single- or second-story windows look into neighbor's house or backyard.

Despite these and opponents' other concerns, Phil Nameny of Portland's Bureau of Planning and Sustainability says the city sees accessory dwellings as a viable component of its housing strategy.

"ADUs provide infill housing opportunities in great neighborhoods, taking advantage of existing utilities and services" like roads, sewers and schools, while "allowing more people to live in amenity-rich areas" near employment, retail centers and transit corridors, he says.

"Their small size translates into a smaller carbon footprint over the lifecycle of the unit," he continues, "and they offer residents a chance to age in place, live closer to family and/or realize additional rental income."

Portland has been supporting secondary units through zoning code changes for two decades. ADUs are allowed in more areas than duplexes, triplexes and courtyard apartments. Most recently, the city announced its Residential Infill Project, which proposes to allow two secondary units per lot in neighborhoods with transit access, says Nameny.

Multnomah County and energy-efficient home advisors at nonprofit Enhabit have proposed a program, called A Place For You, where ADUs would be installed at no cost to owners of private yards to shelter a homeless family for five years. After that time, the landowners would own the dwelling.

The city and county are not alone in cheering on an extra, compact house.

Real estate agents listing modest to multi-million dollar estates are promoting a potentially lucrative perk: A house or yard might accommodate a new, second home that can be rented to reduce mortgage payments. Some new houses include a flexible living space with a separate entrance that grants privacy to a member of a multigenational family or tenant.

An ADU -- which Peterson says can cost as much as a Lamborghini and is usually financed from personal savings or through home equity loans -- can pay for itself over time, and can eventually add to the resale value.

A detached, 800-square-foot second home that cost $160,000 could break even in about nine years if rented at $1,500 a month, says Peterson, who is giving a free, public talk from 6 p.m.-7:30 p.m. on Saturday, Feb. 3, at 2120 NE Tillamook St. in Portland (registration required).

Peterson encourages potential landlords to find out how their jurisdiction assesses ADUs for property tax evaluations. There will also be increases in utility costs, periodic vacancies and other ongoing maintenance expenses.

And yet affordable one- or two-bedroom urban homes are in demand, use less energy and materials in construction, and cost less to heat, cool and maintain. In the end, they seem to pencil out.

Interest among homeowners with equity and a desire to have a second unit has made Portland a leader of ADU development in the United States. Peterson says there has been a 22-fold increase of annual ADU permits over the past 10 years.

In 2016, 615 permits were issued.

And each day, more homeowners are weighing the benefits.

HOW SMALL IS SMALL?

In Peterson's comprehensive book, "Backdoor Revolution-The Definitive Guide to ADU Development" ($15 ebook, $25 print), he targets homeowners who want to learn what it's like to design, build, sleep, shower, cook in or rent a legal spare home.

Over 368 pages, Peterson's first-of-its-kind book spotlights success stories. He offers details on construction, cost, financing and space-saving layouts as well as the development process. Zoning barriers and regulatory loopholes are defined as well.

Peterson is well known as Portland's most public ADU expert.

Free ADU development talk

Kol Peterson, author of "Backdoor Revolution-The Definitive Guide to ADU Development" ($15 ebook, $25 print), is giving a free, public talk from 6 p.m.-7:30 p.m. on Saturday, Feb. 3, at 2120 NE Tillamook St. in Portland. Space is limited so registration is required at

Thousands of people who are curious about or committed to adding a home with a kitchen sink and stove to underused space inside or outside their house have attended Peterson's five Build Small, Live Large: Portland's Accessory Dwelling Unit Tours.

During his events, which have received support from the City of Portland, Metro, Oregon Department of Environmental Quality, Earth Advantage and the Energy Trust of Oregon, participants talk directly to ADU owners, designers and builders.

Peterson finds it's common for grandparents to help finance the investment of building a secondary dwelling, from about $20,000 to $200,000, then live there and help care for the grandchildren.

"It's the quintessential granny flat," he writes. "Simultaneously, the kids are able to look after their aging parent."

In his in-depth book, we learn about a Portland real estate agent who lives with her mom and grown daughter. The trio realized it would cost less for them to buy a nicer home, build an ADU and help each other out than live separately.

A pass-through doorway between the primary house and the ADU allows the grandmother to use a primary-house bedroom as her library and study as an extension of her 800-square-foot accessory home.

In most cases, ADUs are independent from the primary house and the occupants of the two units do not necessarily visit each other's living space, writes Peterson.

This allows people to use the secondary structure differently over time. Since housing is the single largest monthly expense for most Americans, seniors nearing retirement see an ADU as a way to downsize and cut costs while staying in their neighborhood.

Some owners are building small houses that they call home, designed with features to help them age in place. They live there full time and rent out the main house to fund their retirement.

Peterson says these small-footprint development projects can be profitable and "align with much of what Portland is attempting to do right now with creating more residential housing, while maintaining the historic character of neighborhoods."

Ben Waechter of Waechter Architecture in Portland designed a garden house in a client's Southeast Portland backyard. The modern structure has two stories of blue siding outside and a soaring interior living space.

At a generous 800 square feet, it's more than a kid's playhouse.The main residence, a 1940s Cape Cod, steered the style of the little home, which mimics the silhouette of the existing roof.

Some owners opt to match their primary house, but they are no longer required to do so by the City of Portland.

But the ADU does need to be smaller.

How small is small?

Ask Eli Spevak, who serves on Portland's Planning and Sustainability Commission, co-founded Portland for Everyone that advocates for affordable and community-supportive housing, and founded Orange Splot, which designs and builds co-housing and other small communities.

Years ago, he installed two tiny garden cottages that share a 50-foot-by-100-foot residential lot in Northeast Portland with the original house. The first house, which he renovated, is small itself. There's a 526-square-foot main level and a 200-square-foot bedroom in the converted attic.

In another case, Valerie Bryan of Northeast Portland tore down her underused garage and built a detached, 687-square-foot ADU to house out-of-town family and friends, and rent out through Airbnb while increasing the value of her property.

Little homes can range in styles, from farmhouse to glass-box modern, and size, from about 260 square feet -- the size of a single-car garage -- to more than 800 square feet -- the living space of the average U.S. home before 1950.

THE REVOLUTION TOOK ITS TIME

Peterson has been promoting the benefits of second homes on a single-family residential lot to homeowners, environmentalists and government decision makers since 2011.

That year, he and his wife, Deb Delman, built a detached, 800-square-foot home on a slab foundation in their Northeast Portland yard. They moved in and continue to rent out the main house.

It's hard to imagine a couple who have done more to cement the idea of small-footprint living here than Peterson and Delman.

Delman, a former teacher, lived in a garage conversion when the two met. Together, they founded Caravan-The Tiny House Hotel in Northeast Portland's Alberta Arts District that allows people to try out living in 120 square feet.

Their concept -- the world's first lodging of tiny houses on wheels -- helped launch tiny house living blogs and shows, and even a hilarious tight-quarters spoof on the comedy television series "Portlandia," that was shot at Caravan.

Unlike permitted ADUs, tiny houses on wheels can only be lived in temporarily.



While building his home, Peterson started sharing his hard-earned knowledge on AccessoryDwellings.org, a respected online resource that posts case studies and updates the progress of ADUs, which is still a rare form of housing.

For seven years, Peterson has also taught more than 2,000 people about the ADU development process in full-day workshops ($145) that cover cost-saving design and building methods as well as financing and rebates. The next workshop is Feb. 3.

Many of his graduates have completed a secondary home, then agreed to be on one of Peterson's tours.

"In talking to more than 200 ADU owners, I've never met anyone who had financial regrets about building their ADU," he writes. "In fact, it is common for owners to express that it was the most financially life-enhancing move that they ever made."

Bryan Scott, who converted his garage into a 480-square-foot modern, industrial-style loft and rents out his larger house in Southeast Portland's Richmond neighborhood, opened his ADU to Peterson's tour in 2015.

Scott of Zenbox Design, who planned and built the compact home and most of the multipurpose wood furniture in it, and has written about his DIY effort, told Peterson, "Our ADU home has become the roof over our heads, our livelihood and our retirement plan."

-- Janet Eastman



jeastman@oregonian.com

503-799-8739

@janeteastman





10 TIPS TO A BETTER ACCESSORY UNIT

In "Backdoor Revolution: The Definitive Guide to ADU Development" ($25 print, $15 digital), author Kol Peterson offers design ideas he endorses after visiting well-planned small houses, talking with people who specialize in accessory dwelling units (ADUs), and reading books and websites about small-space planning, including books by Sarah Susanka.

Second, smaller homes sharing a city lot are the only housing form typically developed by homeowners, says Peterson, who has a master's degree in environmental planning from Harvard's Graduate School of Design.

Still, he cautions against DIY design for complex, ground-up construction.

Since these second dwellings infill a residential property, their design and placement need to be customized. Peterson says he's never seen two that look alike.

Legal, comfortable second homes, however, do have some features in common. Here are Peterson's insights: