Checklist for building an (ADU) Accessory Dwelling Unit
Table of Contents

Checklist For Building an ADU

“Good fortune is what happens when opportunity meets with planning.” – Thomas Edison

Planning and Preparation: Use our free tools to get a head start on your ADU project research and planning.

  1. Determine eligibility for an ADU using our free check and property report.

  2. Familiarize yourself with the different types of ADUs, local zoning, and regulations.

  3. Use our free property report to determine the right ADU type for your property: 
    • Detached ADU: New construction living space unit, separated from the primary structure.
    • Attached ADU: New construction living space unit, attached to the primary structure.
    • Garage Conversion: Converted existing garage space into an independent living unit.
    • Above Garage ADU: An additional living space unit above the primary garage structure.
    • Interior Conversion ADU: Convert existing Space such as a master bedroom into an independent living unit.
    • Junior ADU (JADU): Small space conversion, up to 400 sqft, that is contained entirely within an existing single-family residence.
    • Prefab ADU: A modular or manufactured dwelling unit that is built off-site and then transported to the property for installation.

  4. Connect with ADU lenders to explore different financing options. 
    • To finance an ADU project, contact a mortgage lender, a local credit union, or a lender referral service. After researching various loan options, obtain pre-approval for a loan amount. Cash, HELOC, cash-out refinance (less popular in high-interest rate environments), or a construction or renovation loan are common methods of payment for an ADU.

  5. Get complimentary consultation and estimates from qualified contractors and architects. 
    • Comparing only the total cost of building estimates can be misleading because each estimate may include different inclusions such as fixtures, appliances, and landscaping. To accurately determine your budget, consider factors such as the contractor’s payment schedule and change order policy that may have an impact on your budget.

  6. Hire a licensed architect or designer to draft plans.
    When selecting a designer for your ADU project, consider the following factors:
    • Specialization in ADUs
    • Experience in obtaining permits in your jurisdiction
    • Knowledge of value engineering
    • Understanding of construction costs
    • Awareness of local regulation changes
    • Possession of a valid license.
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Convert your existing garage
Get a complimentary report to find out your property's ADU potential

Permits and Construction:

  1. Submit plans and apply for necessary permits.
    • Construction drawings for your ADU include important information such as technical calculations and regulatory requirements. A city planner may request revisions, but this is common and usually minor. Interview contractors before the city approve the plans and use The ADU Guide to connect with qualified contractors to find the best fit for your project. Obtain building permits and begin construction after the plans are approved.

  2. Hire your general contractor. 
    • If you work with one of our contracting partners, we will help you with the contractor hiring process. Before signing an agreement, make sure to discuss your expectations for the working relationship with your contractor. Cover communication, work site and workday, subcontractors, and homeowner responsibilities. Inquire about who will be the project manager, how frequently you’ll receive updates, workday start and end times, how tools and materials will be stored, and homeowner responsibilities. Ensure that subcontractors are covered by liability and worker’s compensation insurance and that they are held accountable. Discuss any unresolved expectations or concerns.

  3. Time to start construction!
    • The construction of an ADU involves several stages, including site work, foundation, framing, exterior sheathing, rough-ins, drywall, and finishes and exterior. Site work involves the preparation of the land, while the foundation keeps moisture and groundwater out and distributes weight evenly. Framing is usually made of wood, while exterior sheathing is a protective cover to prevent moisture. Rough-ins are for mechanical, electrical, and plumbing lines. Drywall marks the halfway point of construction, and after it is installed, the interior finishes like cabinetry, flooring, and paint are completed.
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Finishing and Occupancy:

  1. Final inspection and a certificate of occupancy.
    • The final home inspection is when a home inspector examines the plumbing, electrical, and HVAC systems, doors, windows, foundation, roof, and more of an ADU to determine if it’s habitable and safe to live in. If the structure passes the inspection, a certificate of occupancy will be given. If there are any issues, another inspection may be required after they are fixed. If required, register your ADU with local authorities.
  2. Add the ADU to your homeowner’s insurance policy.
    • Adding an ADU to your homeowner’s insurance policy is important to ensure that it is covered against damages and losses due to events like fire, theft, or natural disasters. This can provide financial protection and peace of mind in the event of any unexpected incidents affecting the ADU. Additionally, some cities may require a homeowner to have insurance coverage on an ADU as a condition of obtaining a permit or certificate of occupancy.
  3. Explore the different options of what you can do with your new ADU.
    • Rent it out to generate passive income.
    • Use it to accommodate guests or family members.
    • Make it a home office or workspace.
    • Rent it out as short-term lodgings, such as on Airbnb.
    • It can be used as an in-law suite for an elderly parent or relative.
    • You can live in it while renting out the main house.
  4. Maintain all necessary documentation, including permits, plans, and inspection reports, for future reference, and potential resale of the property.
    • It is important to maintain all necessary documentation, including permits, plans, and inspection reports, for future reference and potential resale of the property because it shows compliance with local building codes and regulations. This document provides evidence of the legality and quality of the construction of the ADU and can be useful for future buyers who want to assess the safety and livability of the property. Having this documentation readily available can also make the selling process smoother and quicker, as the potential buyer does not need to request additional information.