Quotes of the Day

If you're thinking about potential income properties, you may want to take another look at your backyard. Backyard cottages — sometimes referred to as accessory dwelling units, laneway housing, or granny flats — have been cropping up all over the Pacific Northwest, and cities across the nation have started updating zoning rules to allow for dwellings where your swing set used to stand. Seattle, considered a pioneer of the movement, now welcomes Portland, Miami, Berkeley, Denver and Burlington, VT, to the backyard cottage club.

Karen Chapple, a city planning professor at the University of California, Berkeley, says she was intrigued by the burgeoning trend and built her own backyard cottage this year — as a class project, no less — to see the feasibility of backyard cottages as affordable housing options in the Bay Area.

Her 420 square feet cottage — small by comparison to those in Portland and Seattle where the maximum size tops out at 800 square feet — has had a positive effect on her rental income. And on her neighbors. "If you see one go up in your neighbor's yard, people want one," Chapple says. "It spurred about a dozen of these already. The more of these that actually get built, the more people will get inspired," although, at the cost of about $100 per square foot, financing may be the largest hurdle. (Chapple's cottage cost $100,000.)

Still, the idea has merits socially, economically and environmentally, says architect Heather Johnston of Vancouver's Place Architects, who has designed a handful of such cottages. With about 100 units going up in a year in Vancouver and slightly less in Seattle and Portland, clients work to build the maximum size available, says Bruce Parker, founder of Seattle's Microhouse. Each city boasts its own stable of half-dozen companies offering pre-fab units, but they sometimes prove tricky within tight building sites, so traditional construction has proven the most popular.

As the idea spreads, so do the uses. Michael Lyons of Vancouver's Small Works, who has about 20 cottages to his name, says his clients split in three equal groups: grown children moving in behind the family home, homeowners downsizing and renting out the main structure, and a chance for aging family members to remain semi-independent. Ross Chapin, a Seattle architect who builds these cottages nationwide, has even seen an ex-husband relegated to a backyard cottage. Apparently there's no limit to the affordable housing search.

• Tim Newcomb