The Cost of Building an ADU in San Diego in 2024
With housing prices continuing to climb in San Diego, many homeowners are turning to Accessory Dwelling Units (ADUs) as a practical solution to expand living space, generate rental income, or accommodate multigenerational families. However, the cost of building an ADU can vary significantly based on the type of structure and scope of the project.
In this post, we’ll explore the different types of ADUs—attached, detached, garage conversions, and Junior ADUs (JADUs)—and compare their costs. We’ll also cover the key factors that influence pricing, such as design complexity, permitting, and construction timelines, to help you better plan your project in 2024.
Types of ADUs: A Quick Overview
Detached ADU: A stand-alone unit separate from the main house, usually built in the backyard or side yard.
Attached ADU: An addition that’s physically connected to the main house, sharing one or more walls.
Conversion ADU: A transformation of an existing structure (e.g., garage, basement) into a living space.
Junior ADU (JADU): A smaller unit (no more than 500 square feet) that’s typically created within the footprint of the main house, often converting existing bedrooms or other unused spaces.
1. Detached ADU Costs in San Diego
A detached ADU is often the most expensive option due to its standalone nature. Costs are higher because it requires:
New foundations: Unlike attached or conversion ADUs, a detached ADU requires its own foundation, which can add substantial costs.
Separate utilities: Connecting separate water, sewer, and electricity lines can also be costly.
Building new structures: Everything from walls, roofing, and even landscaping has to be constructed from scratch.
Typical Costs for a Detached ADU in San Diego in 2024:
Construction cost: $350 - $500 per square foot
Typical project cost for a 750-1,200 square foot unit: $262,000 - $460,000.
While detached ADUs are pricier, they offer complete privacy and flexibility, making them ideal for rentals or multigenerational living.
2. Attached ADU Costs in San Diego
An attached ADU is physically connected to the primary home, which makes it less expensive to build compared to a detached unit. Sharing walls with the main house reduces the need for extra foundations and separate utility hookups.
Key Cost Benefits of an Attached ADU:
Shared walls reduce the overall construction cost.
Lower utility costs: Since the ADU can share utility lines with the main house, separate connections aren’t necessary.
Fewer material and labor costs: As it’s part of the main home, less structural work is needed compared to a detached ADU.
Typical Costs for an Attached ADU in San Diego in 2024:
Construction cost: $200 - $350 per square foot.
Typical project cost for a 500-800 square foot unit: $160,000 - $280,000.
Attached ADUs are ideal for homeowners looking to add living space for family members, or as rental income, while keeping costs more manageable.
3. Conversion ADU Costs in San Diego
Garage conversions and other conversion ADUs involve repurposing an existing structure, like a garage or basement, into a livable unit. Since the primary structure is already in place, conversion ADUs can be a more cost-effective option.
Advantages of Conversion ADUs:
Lower construction costs: No need to build new foundations or walls, and utility lines can often be shared with the main house.
Faster completion time: Since you’re not building from scratch, conversions can often be completed more quickly than other ADU types.
Typical Costs for a Conversion ADU in San Diego in 2024:
Construction cost: $150 - $350 per square foot.
Typical project cost for a 400-600 square foot unit: $100,000 - $210,000.
Conversion ADUs are perfect for homeowners who want to maximize unused space (like garages or basements) without the expense of building a new structure.
4. Junior ADU (JADU) Costs
A Junior ADU (JADU) is a smaller, more compact version of an ADU, typically no larger than 500 square feet. They’re created by converting part of an existing home (like a spare bedroom or portion of a garage) and often share amenities like bathrooms or kitchens with the main house.
Why JADUs Are the Most Affordable Option:
Minimal structural changes: Since they’re created within the existing home’s footprint, there’s no need for new foundations or major construction.
Shared utilities: JADUs typically share utility lines with the main house, saving on installation costs.
Typical Costs for a JADU in San Diego in 2024:
Construction cost: $150 - $200 per square foot.
Typical project cost for a 300-500 square foot unit: $90,000 - $200,000.
JADUs are a great option for homeowners looking to add living space for family or rent out a small unit without a large financial commitment.
Which ADU Option is Right for You?
When deciding on the type of ADU to build, it’s essential to consider both your budget and your needs:
Detached ADU: Best for complete privacy and separate living quarters, but at a higher cost.
Attached ADU: Offers a middle ground, with shared walls and utilities keeping costs lower than a detached unit.
Conversion ADU: Ideal for homeowners who want to repurpose unused space without the expense of new construction.
Junior ADU: The most affordable option, perfect for smaller households or homeowners on a tight budget.
Final Thoughts: Making the Most of Your ADU Build in 2024
No matter which type of ADU you choose, it’s essential to work with experienced contractors and architects who understand San Diego’s zoning laws and building regulations. As ADU popularity continues to rise, getting the right guidance will ensure your project stays on budget and meets all local requirements.
If you’re considering building an ADU in 2024, our team at SoHo Construction can help you navigate the process, from design to completion. Contact us today for a consultation and let’s bring your vision to life.
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