Designed as a "green" prototype, the cottage is constructed with sustainable lumber, recycled metal roofing, well-insulated walls, non-volatile paint and a gas on-demand water heater.
Currently rented to a pair of firefighters and their young son, the cottage has a tight but high-ceilinged living room, a narrow kitchen with granite countertops and a miniature dishwasher, a dining-office nook, a conventional 5-by-7 bathroom, and a sleeping loft reached via a ship's ladder. A shed-roofed porch spans the gable-ended entry facade.
Chapple, director of the Center for Community Innovation, leads a study funded by the University of California Transportation Center "to determine how many accessory homes could be built around five Bay Area Rapid Transit stations, and how they might affect the local economy." Berkeley has as many as 4,000 backyard cottage infill sites, according to the study's preliminary findings. A metropolitan area could have hundreds of thousands of such sites.
Chapple and her study team envision infill accessory dwellings as a potentially cost-effective, sustainable densification strategy for existing communities, a strategy that could augment transit usage and viability while expanding and diversifying affordable-housing opportunities. And it's theoretically a strategy applicable anywhere in the United States.
But as logical and beneficial as the strategy seems, scaling it up for widespread implementation faces legal, technical, economic and political obstacles, whether in California or metropolitan Washington.
l Regulatory impediments. Few zoning ordinances allow accessory dwelling units on lots in one-family residential zones, where neighborhood population and dwelling unit density are purposely limited. Parking regulations also can be problematic, since most city and county zoning ordinances mandate at least one on-site parking space for each one-family dwelling unit. Many subdivision lots do not have room for an extra car.
l Physical site challenges. Unfavorable topographic conditions and poor drainage can complicate construction of a backyard cottage. Mature trees and other valuable landscaping worth protecting can be in the way. Transporting construction equipment, prefabricated components and building materials into a back yard may be troublesome if side yards are too narrow or obstructed. Installing new utility lines running across a back yard to the cottage can be difficult and expensive, especially if water and sewer mains are not in an easement or alley at the rear of the lot.