Attached ADU
Add more space and value to your property with this type of ADU. Whether you need room for family, guests, or rental income, an attached unit is a practical, efficient solution.
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It’s built directly onto your existing home, either to the side, rear, or even above a garage. Because of its shared structure, attached ADU is often quicker to build and more budget-friendly.
Benefits
Why Choose an Attached ADU?
Lower Costs
Shared walls and systems reduce construction costs for this ADU type.
Streamlined Permitting
Attaching an ADU often results in faster, simpler permitting processes.
Efficient Use of Space
Ideal for narrow lots or homes with limited yard space.
More Privacy
Separate entrances, private patios, and soundproofing offer increased privacy.
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How Homeowners Use an ADU Attached to House
In-Law Suite
A great way to keep loved ones close while maintaining independence.
Rental Income
Turn unused space into a legal rental with consistent monthly income.
Guest Apartment
Offer a comfortable, private stay for visiting family or friends.
Home Office or Studio
A side-by-side ADU layout can give you a peaceful, dedicated workspace.
prices
What’s the Attached ADU Cost?
ADU Type
Basic Studio Attached ADU
1-Bedroom Attached ADU
2-Bedroom ADU Attached to House
Attached Garage ADU Conversion
Price
$120,000 – $150,000
$160,000 – $200,000
$190,000 – $240,000
$100,000 – $140,000
ADU Type
Basic Studio Attached ADU
$120,000 – $150,000
1-Bedroom Attached ADU
$160,000 – $200,000
2-Bedroom ADU Attached to House
$190,000 – $240,000
Attached Garage ADU Conversion
$100,000 – $140,000
Cost Estimate
The cost of an attached ADU California depends on things like size, design, materials, and your property’s layout. Check out our calculator for a more accurate estimate.
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Sample Attached ADU Floor Plans
Silverstone Annex
Silverstone Annex
A bright and airy 400 sq ft unit for an aging parent, complete with wide doorways and no steps
Silverstone Annex 2
Silverstone Annex 2
A bright and airy 400 sq ft unit for an aging parent, complete with wide doorways and no steps
FAQ
Answers to Your Attached ADU Questions
Is an attached ADU legal in my area?
Yes! Attached ADUs are allowed across most of California, including Los Angeles. Local rules apply, and we help you navigate them.
How long does an attached ADU construction take?
Usually takes 6 to 9 months, depending on the project size and permit approvals.
Can an attached ADU be rented out?
Absolutely. In most cases, you can legally rent your unit long-term and sometimes short-term.
What’s the difference: attached vs detached ADU?
An attached ADU shares part of the main home, while a detached ADU stands alone. Attached versions often cost less and are faster to permit.
Thinking About an Attached ADU?
Whether you're exploring ideas or ready to move forward, we’ll help you see what’s possible on your property - clearly and confidently.
More information
An attached accessory dwelling unit connects to your home and gives you more usable space. It’s a great way to add a living area without losing your backyard. With a shared wall or roofline, it often costs less than building a separate unit. Homeowners across California are using this option to add flexible living space while keeping construction simple.
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An attached accessory dwelling unit connects to your home and gives you more usable space. It’s a great way to add a living area without losing your backyard. With a shared wall or roofline, it often costs less than building a separate unit. Homeowners across California are using this option to add flexible living space while keeping construction simple.
Getting an ADU permit is complicated, especially with zoning rules and construction codes that vary by city. We take care of the details. ADU Scale handles your feasibility analysis, design, permitting, and project planning - so you don’t have to.
We focus on attached ADUs Los Angeles and throughout California’s counties. Our team understands local codes and works with trusted partners to keep your project smooth, on time, and on budget.
What We Offer
- Personalized site analysis
- Transparent pricing and timelines
- Experts in California attached ADU regulations
- Start-to-finish project guidance
How It Works
- Free Feasibility Check - Find out what’s possible on your property
- Design & Estimate - Custom layout options for your lifestyle and budget
- Permit & Plan - We submit all applications and work with your city
- Build with confidence by partnering with a reliable ADU company and skilled team to make your project a reality.
Since the attached secondary residence integrates with your home, it can often be connected to existing plumbing, electrical, and HVAC systems - reducing both cost and build time. In many cases, fire separation requirements and property line setbacks are more flexible for attached units than detached ones. This can be especially useful on narrow or sloped lots common in areas like Los Angeles.
Attached ADUs are also ideal for future-proofing your home. Many homeowners build them as flexible-use spaces - starting as a home office or guest suite, then transitioning to a rental or in-law unit as needs change. We help you plan for both your present and your future with smart design and expert guidance tailored to California’s evolving ADU regulations.