ADU Costs & Options in LA: Everything You Need to Know

ADU Types & Construction

Accessory Dwelling Units are known by many names: ADUs, Granny Flats, Backhouses, Secondary Units, and Garage Conversions. By now you should know that California approved AB2299 & SB1069 a few years ago to permit homeowners to build profitable units in single-family and even multi-family neighborhoods. But do you know how much an ADU construction costs in Los Angeles?

If you’re considering starting an ADU construction in Los Angeles, this article will help you understand how much you’ll spend on permit fees, architectural plans, and the overall price you’ll pay to build one. We will also cover the general price range of different types of ADUs in the city of Los Angeles, Los Angeles County, and all major cities in Los Angeles County.

ADU Construction Types & Costs

The most common question people have is “How much does an ADU cost?” In construction, the cost is a factor in the amount of work being done. If you increase the scope of work, you will also increase the price tag. These are the 3 main types of ADUs along with a brief description of the amount of work you will need to build it.

1. Garage Conversion ADU (can be attached or detached) – Rehab/Remodel

2. Attached ADU (similar to an addition) – New Construction

3. Detached ADU (ground-up design) – New Construction

Garage Conversion (400SF – 500SF)

ADU Construction in Los Angeles

A Garage Conversion is usually the cheapest construction of all types of ADU because the framework already exists, but you may still need some work. The construction cost is the lowest when the garage is at the front of the lot with easy access to the sewer system. This makes it so much easier. Normally in this scenario, the roof of the garage will have to be reformulated, you will have to add wall insulation, and you will need an electrical upgrade.

Required Construction Documents $10,000 – $185,000

  • Architectural Floor Plans & Site Plans
  • Engineering Plans (for the wall, roof, and ceiling framing)
  • Title 24 Report (energy calculations are required by law)
  • Electrical Plan (for service panel & electrical wiring)

Construction Costs $100,000 – $120,000

If you are contemplating a Garage Conversion, you can expect to pay between $10,000 and $15,000 in pre-construction expenses. All these plans are required by your local municipality in order to get your project approved and allowed. For a good quality Garage Conversion, you can expect to spend between $100,000 and $120,000. This will get you an ADU studio style with a small kitchen and bathroom with good quality materials and finishes.

Attached ADU (300SF – 700SF)

Types of ADU

An Attached ADU is similar to a home addition because it is connected to the main structure but is a separate unit. The unit will have its own access, and depending on the city, it may also have its own address. These types of ADU are a bit intrusive during construction because they often share the main sewer line and the electrical system. You will need to upgrade your power panel to at least 200 Amp in order to handle the increased loads. Some municipalities require a two-meter electrical panel.

Required Construction Documents $15,000 – $20,000

  • Architectural Flooring and Site-Plan
  • Engineering Plans (for the wall, roof, and ceiling framing)
  • Title 24 Report (energy calculations are required by law)
  • Electrical Plan (for service panel & electrical wiring)
  • Soils Report
  • Property Survey

Construction Costs $180,000 – $220,000

For an attached ADU you can expect to pay between $15,000 and $20,000 in pre-construction expenses. All of these reports and plans will be needed for your project to be approved by the local zoning department. You will need a complete set of plans to submit to the city for review and revision of the plan, once approved; you can get a permit to begin construction.

Detached ADU (350SF – 1200SF)

ADU Construction management in Los Angeles

With a Detached ADU, you’ll be able to design your ADU from the ground up, which means you can probably build a bigger ADU which can potentially get you higher rents. If your lot is large enough you can build a Detached ADU up to 1,200 SF or 50% of the existing home’s footprint. A Detached ADU offers all the comforts of new construction, tenants will enjoy new insulation, air conditioning, noise-reducing double pane windows, and they’ll enjoy private access to their own unit.

Required Construction Documents $18,000 – $24,000

  • Architectural Flooring and Site-Plan
  • Engineering Plans (for the wall, roof, and ceiling framing)
  • >Title 24 Report (energy calculations are required by law)
  • Electrical Plan
  • Survey of Lot
  • Soils Report

Construction Costs $250,000 – $300,000

For a Detached ADU you can expect to spend anywhere between $280,000 to $300,000+ to build an ADU that is comfortable and luxurious. Your tenants and family alike will enjoy the modern amenities of a large detached ADU.

Want to learn more? We have a great library of blog articles available to you so you can be better educated about all your options when planning a second unit project. Want to speak to an expert? Contact us at (310) 974-3174 to book a complimentary consultation for ADU Construction in Los Angeles.