Cost to design and build a one-bedroom accessory dwelling in El Cerrito, CA
Dennis and Lisa, two young parents from El Cerrito, CA, contacted us in the summer of 2011 with the idea of replacing an old chicken coop in their backyard with a nice little cottage for Dennis’ mother. Having grown up nearby, Dennis wanted to invest wisely in their character-rich property, which has amazing gardens and a view of the Golden Gate Bridge.
This unused chicken coop was replaced with a beautiful accessory dwelling for Dennis' mother to live in.
The family has a sizable and interesting yard. Three homes in a row were once shared by a single family, so no fence separates Dennis and Lisa's home from their neighbor’s home. Various small clearings in the yard hold a children’s playset, a chiminea fire pit, a hot tub, and a swinging bench. In the very rear section of the yard sat an old chicken coop they inherited and used for storage. Lisa is a former plant dealer with some experience in landscaping. Pebbled paths traverse the yard, winding through succulents, agave, trees, shrubs, and potted flowering plants. Altogether, the yard paints a welcoming lush and colorful desert scene.
During the early design stages, we discussed some options with Dennis and Lisa. The first design was a sloped 850-square-foot modern home with a loft and shed roof. This had two bedrooms, one bathroom, and a living/kitchen area.
A line rendering for a two-bedroom accessory dwelling
Elevations from the original design
A floorplan for a two-bedroom accessory dwelling
After some thinking, though, this scheme was scrapped in favor of a more classic cottage design. The second design is a 600-square-foot L-shaped home with one bedroom, one bathroom, a living/kitchen area and a gable roof and loft. Just outside the house is a great outdoor patio and trellis for rest and relaxation.
The line rendering of the one-bedroom design Dennis and Lisa chose
Elevations from the design chosen by the homeowners
The floor plan for the one-bedroom with attic design that Dennis and Lisa chose
The cottage was designed with energy efficiency in mind. It will feature passive heating. Big glass doors on the southeast side of the house and a large salvaged window along the south wall will allow the sun to heat the first floor’s slab all day long. A metal roof will reflect heat in the summer, and a small gas fireplace will help heat the house when needed.
Other notable features of the project include:
Stained concrete throughout the first floor and carpeting upstairs
A salvaged cast-iron tub to be provided by the owner
An Integrity French door for main door
HardiePlank lap siding
Gas fireplace, stove, and dryer
Pendant lighting in the kitchen
Wood tansu stairs (stairs with storage built-in storage)
The project broke ground in March 2013. Much of the backyard was cordoned off beforehand to preserve a rare, irreplaceable pepper tree and the intricate landscaping. The old chicken coop was demolished to make room for the new cottage. Because of the city’s strict height limit rules and the need for a more secure foundation, earthwork involved digging down a couple of feet. Excavated remained onsite to be used for landscaping and minimize hauling expenses.
Preserving the landscape while building an ADU takes planning and patience, but it can be done.
Dennis and Lisa's backyard cottage will be the perfect home for Dennis' mother, and it will be an asset to the family for generations to come.
The total cost to design and build this project was 240,322.75 in 2012. Today, a project like this would cost around $280,000. You can view the complete budget below.
