ADU Garage Conversion Cost

ADU Garage Conversion Cost

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Looking for an ADU Garage Conversion Cost?  Then this article is for you.  However, before we dive in, let’s begin by stating that not all garages are the same.  They vary in size, age, placement, architecture, and structural engineering and integrity.  Some garages are attached to a primary residence, while others are detached and located far away from the residence.  All of these factors will impact the overall ADU Garage Conversion Cost.  With that in mind, let’s dive in.

ADU Garage Conversion Cost Components

  • ADU Garage Conversion Plans & Design
  • ADU Garage Conversion Engineering (if needed)
  • ADU Garage Conversion Permits
  • ADU Garage Conversion Construction

Additional ADU Garage Conversion Cost Components include utility fees and project management and coordination fees.

ADU Garage Conversion Cost: Plans & Design

Plans must be drafted and completed in order to convert your garage into an ADU or Junior ADU.  This can be done by an architect, draftsman, or designer.  The cost for this varies widely and can be as low as $2,500 and as high as $40,000 in our area of Orange County, CA.  

ADU Garage Conversion Cost: Engineering

Engineering for a garage conversion may not always be needed.  However, if you are making structural changes or adding windows and doors, engineering will be required.  The cost for structural engineering will depend on how much structural work needs to be done and can vary from $350 – $4,000 or more.  Title 24 calculations will need to be completed by an electrical engineer and ranges from $250 – $1,500 or more.

ADU Garage Conversion Cost: Permits

Permits are issued by your city and the cost is determined by them.  The ADU Garage Conversion cost for permits ranges from $1,500 – $5,000 or more.

ADU Garage Conversion Cost: Construction

The ADU Garage Conversion Cost for construction will vary based on several factors, such as the size of the garage, the materials used, and whether you’d like separate utilities for the ADU.  The construction cost can vary from $150 a square foot up to $250 a square foot or more in our area.

ADU Garage Conversion Cost: TOTAL

  • ADU Garage Conversion Plans & Design: $2,500 – $40,000+
  • ADU Garage Conversion Engineering: $0 – $5,000+
  • ADU Garage Conversion Permits: $1,500 – $5,000+
  • ADU Garage Conversion Construction: $150 – $250+ per square foot

ADU Garage Conversion Cost Example: 400 square foot garage

If you are on the low end of all of these categories, you may be able to convert a 400 square foot garage into an ADU for around $65,000.  However, this would-be best-case scenario and does not factor in new utilities for the ADU.  The average ADU garage conversion cost usually ends up somewhere in the middle of the range on these four categories, which is closer to $100,000.  However, the cost is highly dependent on the type of finishes installed and the utilities.  Additionally, if you’d like extra features installed, such as patio doors or laundry facilities, the cost will go up.

*Please note: Some people have garages that are already partially converted, in which case, the ADU Garage Conversion cost could be much lower.  On the other hand, some people have old garages with serious structural issues, in which case, the cost could be even higher.

ADU Garage Conversion Cost: The Exact Amount

The best way to find out the ADU Garage Conversion Cost for your specific garage is to connect with an ADU company that offers all of these services.  At Superior ADUs, we take care of the plans, engineering, design, permitting, construction, and project management and coordination.  Additionally, we even have an ADU Garage Conversion Model.  The plans for our ADU Garage Conversion Model are already complete and can be submitted to your city for approval following a site visit and a few plan modifications.  We also offer Custom ADU Garage Conversion plans, where we’ll customize the floor plan to meet your needs.  Our team then handles the permitting process and all of the communication with your city, while our interior designer works with you to choose suitable materials and finishes.  Finally, our trusted contractors build your ADU, while out project managers oversee the entire process.

If you’re located in or around the Orange County, CA area, contact Superior ADUs to get a quote to convert your garage into an ADU.  We will then assess your property and be able to give you an accurate ADU garage conversion cost specific to you and your garage.

Phone: 949-216-0686


Disclaimer: Please note that all numbers and estimates on this page are only approximations based on current building costs in our area of Orange County, CA, and are intended for learning purposes only.  It is always best to consult an ADU builder in your area, have them see and assess your property and project requirements, and then provide you with an accurate cost, which could be lower or higher than the examples provided.

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