ADU Knowledge
July 6, 2024

Is it worth converting a garage to ADU?

Argi Avetisyan
Argi Avetisyan
Gather ADU expert
Is it worth converting a garage to ADU?
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Thinking about converting your garage into an Accessory Dwelling Unit (ADU)? You're not alone. Many homeowners and real estate investors are exploring this option to maximize their property’s potential. In this comprehensive guide, we’ll cover everything you need to know about the benefits, process, and financial considerations of ADU conversion.

Introduction to ADUs and Their Benefits

ADUs, or Accessory Dwelling Units, are secondary housing units built on the same lot as a primary residence. They can be attached, detached, or even part of the existing structure, like a converted garage. These units have gained popularity for their versatility and benefits, such as providing additional living space, generating rental income, and increasing property value.

Why Consider an ADU?

ADUs offer multiple advantages:

  • Additional Income: Renting out an ADU can provide a steady stream of rental income.
  • Extra Living Space: Ideal for accommodating extended family or guests.
  • Increased Property Value: Well-executed conversions can significantly boost property value.

Pros and Cons of Converting a Garage to an ADU

Before making any decisions, it’s essential to weigh the pros and cons of converting your garage into an ADU.


  • Cost-Effective: Utilizing existing structures can save construction costs.
  • Quick Permitting: Easier and faster to permit than building a new structure.
  • Efficient Use of Space: Transforms underutilized space into valuable living area.


  • Loss of Parking: Eliminating your garage can reduce covered parking options.
  • Potential High Costs: Upgrading utilities and meeting building codes can be expensive.
  • Neighborhood Restrictions: Homeowner associations or local regulations may pose challenges.

Do You Need Permission to Convert Your Garage?

Garage Conversion to an ADU

Short answer: Yes! Before you start any construction, you need to ensure your local authorities allow garage conversions. Every city and county has different rules, so it’s crucial to get local approval.

Navigating Local Regulations

  • Check Local Ordinances: Understand the specific requirements in your area.
  • Homeowners’ Association: Some neighborhoods may have additional rules and require HOA approval.
  • Land Boundary Considerations: Ensure your conversion complies with property boundary regulations.

Financial Considerations for Homeowners and Real Estate Investors

Converting a garage to an ADU is a significant investment. Understanding the financial implications can help you make an informed decision.

Budgeting for Your ADU Conversion

  • Construction Costs: Expect to spend over $100,000 on an average conversion.
  • Permitting Fees: Vary by location but are necessary for legal compliance.
  • Utility Upgrades: Plumbing and electrical upgrades can add to the overall cost.

Return on Investment (ROI)

  • Rental Income: Calculate potential rental income to offset costs.
  • Property Value: Consider how the ADU will impact your home’s market value.
  • Market Demand: Analyze local rental markets to ensure demand for ADU rentals.

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The Process of Converting a Garage to an ADU

Ready to get started? Here’s a step-by-step guide to converting your garage into an ADU, including legal and regulatory requirements.

Legalizing Your Garage

  • Obtain Original Building Permits: Ensure your existing structure is legal.
  • Bring Up to Code: Update any out-of-code elements, such as windows or walls.
  • Plan Submissions and Inspections: Work with professionals to submit plans and pass inspections.

Understanding the Inspection Process

Typical inspections include:

  • Structural Elements: Walls, roofs, and foundations.
  • Insulation: Wall and ceiling insulation for comfort.
  • Utilities: Electrical and plumbing installations, including off-grid options.

Does Converting a Garage to an ADU Add Value?

A well-planned ADU conversion can add significant value to your property, but several factors come into play.

Assessing the Condition of Your Garage

  • Structural Integrity: Ensure the garage foundation, framing, and roof are in good condition.
  • Cost vs. Benefit: Weigh repair costs against the potential ROI of the ADU.

Market Impact

  • Parking Considerations: Evaluate how the loss of a garage might impact property value.
  • Neighborhood Trends: Understand local real estate trends to gauge potential ROI.

Garage Conversion Cost Considerations

Garage to an ADU

The cost of converting a garage to an ADU can vary widely based on several factors.

Factors Influencing Costs

  • Scope of Work: Larger projects with more upgrades will cost more.
  • Location: Construction and permitting fees vary by region.
  • Upgrades Needed: Consider costs for meeting codes, structural improvements, and utility upgrades.

Average Costs and Timelines

  • Budget: Plan for costs over $100,000.
  • Timeline: Expect a timeline of approximately nine months from start to finish.

Foundation and Flooring

Most garages are built on a concrete slab, which may need modifications for an ADU conversion.

Key Considerations

  • Slab Integrity: Ensure the slab is thick enough and properly constructed.
  • Insulation and Moisture Barriers: Add these to create a comfortable living space.
  • Floor Leveling: Level the floor to prevent water seepage and improve comfort.

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Walls, Windows, and Doors

Adding insulation, windows, and doors is crucial for creating a livable space.

Insulating Walls

  • Add Insulation: Create an airtight, comfortable living environment.
  • Ceiling Joists: May need additional support for insulation and drywall.
  • Check for Asbestos: Ensure safety by checking for hazardous materials.

Windows and Doors

  • Natural Lighting: Install windows for light and ventilation.
  • Functionality: Consider internal partitioning for privacy.
  • Garage Door: Decide whether to keep, replace, or repurpose the door.


Upgrading utilities is often the most expensive part of converting a garage to an ADU.

Electrical and Plumbing

  • Existing Hookups: Determine if the garage has existing electrical and plumbing hookups.
  • Routing Utilities: Assess the ease of routing utilities from the main house.
  • Separate Meters: Consider installing separate meters for rental purposes.

Lighting and Plumbing

  • Lighting Circuits: Add circuits as needed for adequate lighting.
  • Plumbing Lines: Consult a plumber for drainage solutions and water line installation.

Garage ADU Designs and Requirements

Designing your ADU requires attention to both aesthetics and regulations.

Design Considerations

  • Attached vs. Detached: Different regulations apply based on attachment.
  • Space Requirements: Minimum square footage for bathrooms, kitchens, and living areas.

Material Regulations

  • Building Materials: Ensure compliance with local regulations for siding and roofing materials.

Closing Thoughts

Converting a garage to an ADU can be a worthwhile investment for homeowners and real estate investors. The process involves careful planning, budgeting, and adherence to local regulations, but the potential rewards in rental income and property value make it a compelling option. If you’re ready to maximize your property’s potential, consider starting your ADU conversion today.

For more information and professional guidance, don’t hesitate to Contact our ADU experts who can help you through every step of the process. Happy converting!

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Not sure where to start with your ADU project?


Not sure where to start with your ADU project?

Book a free call