Cost to replace a detached garage with a one-bedroom accessory dwelling in Berkeley

These clients own a lovely home on a corner lot in Berkeley. They chose to replace their detached garage with a 651-square-foot accessory dwelling unit. This is a smart move in Berkeley because of the high demand on housing. They’ll be able to rent out their ADU for extra income or use it for themselves or family. A functional building like this can serve many purposes over its long lifetime.

The final design is for a 651-square-foot, one-bedroom, one-bathroom ADU with a kitchen/dining/living area and a laundry closet. 

Adding solar power

The clients were interested in improving the energy efficiency of their new building and opted to place solar panels on the south-facing roof. New Avenue’s partner designer incorporated the panels into the plans, including a gorgeous dormer as part of the roof design.

Relocating a driveway (and more)

Adding an ADU often requires additional changes to the property. In this case, we needed to demolish the existing driveway on the west side of the property (which led to the detached garage) and place a new driveway on the south side to keep parking accessible. Changes to the existing concrete paving were also required. To make full use of the property, we needed to demolish the existing wood fence, which was not on the property line, and build a new fence along the property line.

Special considerations in adding an accessory dwelling in Berkeley

In all construction projects, special considerations must be made to ensure compliance with state and local codes. These include environmental and safety codes. New Avenue ensures that all requirements, such as the California Green Building Standards Code and the Title 24 building code, are met. New Avenue also handles the permitting process.

This site was analyzed by a soils engineer (which costs a few thousand dollars), and the site is all clay (which is common). Clay expands when it gets wet in the rainy winter season and contracts in the dry summer months. The expanding and heaving clay will crack and buckle a foundation like a cracker in your pocket. This small site needed an excavation four feet deep and four feet beyond the perimeter. Next, it needed backfill with gravel, which was then compacted with a tamper downer. This is a major—but necessary—process.

We used this excavator for the excavation work. This photo was taken from a second-floor window of the main house.

Here’s what it cost to demolish a garage, move a driveway, and build an ADU with solar panels in Berkeley.

The total bid for this project was $316,465.50. You can view the complete budget here: Budget for 651sf ADU and driveway

For more examples, you can view another Berkeley ADU project here.

These clients realized their dreams and will get more from their property for generations.

This is a great example of how you can maximize your property. To find out how you can get more from the property you already own, schedule a free call today. Our project manager will call and help you discover your home’s potential.