Prefab vs Custom ADU: What is Better in 2024?

When expanding your living space with an Accessory Dwelling Unit (ADU), choosing between a prefab unit and a custom build is a significant decision. Each option offers distinct advantages and potential drawbacks, depending on your specific needs, budget, and timeline. 

This guide will help you navigate the prefab vs custom ADU landscape in 2024, making an informed choice for your property.

Custom ADU

Custom ADUs are designed and built from scratch, tailored to the homeowner’s specific requirements and the property’s unique characteristics.

prefab vs custom adu

This approach allows for complete control over the design, materials, and layout. As a result, the new structure perfectly complements the existing home and meets all individual needs.


  • Tailored design to match your property and preferences.
  • Flexibility in choosing materials and finishes.


  • Typically more expensive due to the bespoke design and construction process.
  • Longer timelines from design through to completion.

Prefab ADU

Prefab ADUs are manufactured off-site in a factory setting and then transported to your property for assembly. This method has gained popularity for its efficiency, cost-effectiveness, and reduced construction time.

prefab vs custom adu

For instance, one of my acquaintances invested in an ADU back in 2021 in the Bay Area. Due to the shorter permitting process and build time, she was able to get it up within just 14 weeks!


  • Faster construction and installation process.
  • Often more affordable than custom builds.


  • Limited customization options compared to custom ADUs.
  • Possible site preparation challenges, depending on the property.


Which is Faster?

The first question people wonder about in the prefab vs custom ADU debate is about building time.

Prefab ADUs generally lead in speed, with the construction and assembly process taking a fraction of the time required for a custom build. This quicker timeline can be particularly appealing for homeowners looking to expedite their ADU project.

Which is Cheaper?

Yet another aspect of prefab vs custom ADU is the cost factor.

Unsurprisingly, prefab units are typically more cost-effective than custom ADUs. The standardized manufacturing process and reduced labor costs contribute to the lower price point, making prefab a budget-friendly option for many homeowners.

Which One is More Ideal for Your Property?

The best choice depends on your specific conditions, including budget, design preferences, and timeline:

  • If customization and matching the existing property aesthetic are priorities, a custom ADU may be the better option.
  • For those seeking a quick and cost-effective solution, a prefab ADU could be the ideal choice.


Choosing between a prefab and custom ADU in 2024 depends on your unique needs, preferences, and constraints. Consider the pros and cons of each option carefully to determine which approach best suits your project goals.

At GoldenADU, we bring a wealth of expertise in ADU development to help you solve dilemmas like these. Contact us today at 213-693-2405 to get your free ADU consultation for which ADU type to invest in!


Can prefab ADUs be customized at all?

While customization options are limited compared to custom builds, some prefab companies offer a range of finishes and layouts.

Do prefab ADUs require permits?

Yes, prefab ADUs still require the same permits and inspections as custom builds to ensure compliance with local regulations.

How long does it take to install a prefab ADU?

Installation can be completed in a matter of weeks, significantly faster than the months required for custom construction.

Why might someone choose a custom ADU over prefab?

Custom ADUs offer unparalleled design flexibility and the ability to perfectly match the existing home and landscape.

Are there financing differences between prefab and custom ADUs?

Financing options exist for both, but prefab ADUs may be more straightforward to finance due to their lower cost and quicker turnaround.

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