Custom Design Vs. Prefab ADUs I California ADU

Custom Design Vs. Prefab ADUs I California ADU

What Makes ADUs Better Than Container Homes?

We generally hear a lot of questions about the best alternative housing options from our clients. As an established ADU building business, we get many clients interested in getting the best possible option in their backyard. However, with so many options available, making a choice isn’t really that easy. 

What Makes ADUs Better Than Container Homes?

After the staggering increase in housing after the house market collapse in 2008 (and the general economic crisis), people have been looking for alternative housing options. Whether they needed a cheaper place to stay or something that would provide some extra income (or a place for their loved ones), ADUs and other alternative housing options proved to be the best substitute for the All-American cookie-cutter white-picket-fence life. 

But picking the best alternative housing option proved to be a more significant challenge than most people initially thought. 

The Many Faces of Alternative Living

Not that long ago, we talked about the differences between typical ADUs and container homes. With the popularity of alternative housing growing steadily each year (especially during the pandemic) due to the increasing affordable housing shortage, more and more people are interested in setting up additional dwelling units in their backyards. 

Overall, there are two different types of accessory dwelling units:

  • custom 
  • prefabricated

The Many Faces of Alternative Living

Or, in short — custom and prefab. One of the most famous prefab constructions are container homes, which we talked about recently. If you haven’t read our blog post about them, here’s the gist of it:

  • Shipping container homes are affordable because buying a shipping container provides you with already built walls and floors. Not to mention, there’s no need for foundations.
  • Building a shipping container house is easier because you’re not building it as much as installing it.
  • Shipping container homes are durable (given that they are steel) and eco-friendly.

So, prefab ADUs sound great, right? Of course! However, let’s not forget that typical ADUs that are custom made and built on the spot also have some significant benefits, especially compared to container homes:

  • They offer more space, and the custom design allows for easier changes.
  • ADUs increase property value more than container homes do. 
  • They provide more space since the only thing limiting you is the size of your backyard and budget (and not the size and shape of the container). That means you can use every last inch of your yard square footage.
  • It’s easier to find a contractor who can build a custom ADU.

The Question of Choice

 Pros and Cons

When people weigh the benefits of both prefab and custom ADUs, they still have many questions. For example:

  • Are prefab constructions cheaper than custom ADUs?
  • What’s the ROI like in both these structures?
  • Is it faster to build a custom-made ADU or just install a container?
  • Should I buy pre-drawn plans and just DIY this whole thing?

Because we know answering these questions on your own can be a daunting task, we’re here to lend a hand! As a company with many years of experience in the ADU business, we’re more than capable of providing answers. And because we love keeping our clients informed, we prepared all of them in this blog post. So keep reading to find out!

Custom Vs. Prefab — Pros and Cons

It’s important to note that you’ll need to go through the same process of obtaining a building and zoning permit for both custom ADUs and prefab homes. No matter which route you opt for, you’ll need to check the requirements of your city or neighborhood and ensure that you can even build anything at all. 

Luckily, the requirements for ADUs in California are quite lax as of late. During the past five or so years, the government has been steadily making progress when it comes to allowing more ADUs to be built in dense areas. That’s why the number of ADUs in California has skyrocketed.

Container Homes Are Cheaper

Container homes require installation as well as structural changes. You need to reinforce all walls that you make holes in and add insulation. However, since you’re not starting from scratch, your labor costs are lower than they would be if you were. You also don’t need as much material. Remember, you already have four walls, a floor, and a roof. 

But Custom ADUs Offer More Value

Now, cheaper isn’t always better, especially in construction. A custom ADU might take more time, effort, and money, but the end result is worth it. An ADU will add value to your property, which is essential if you plan to sell it eventually. 

That’s not all. ADUs are famously excellent money-makers. You can rent them out and be a landlord without actually having the responsibility of renting out a huge property. But you can also make some money off of your ADU if you’re in a pinch. Thanks to recent law changes, you can now sell your ADU independently of your main single-family house. 

Custom Fits Better

A shipping container home is limited when it comes to size. Even if you use more than one container, you’re still limited when it comes to design. With a custom ADU, you can use space more efficiently and plan an ADU that’s a perfect fit for you.

But Prefab Are Eco-Friendlier

Prefab tiny homes, especially shipping container homes, are the most eco-friendly alternative housing solution (if we don’t count houses made entirely of natural materials). The construction process is less wasteful, and you need fewer materials as well as less labor to make a prefab house. 

Custom ADUs Offer More Room For Your Vision

As always, the clue is in the name. Custom ADUs offer more customization options. If you have a tiny backyard or a space for an ADU that’s too narrow, a prefab home might not fit into it. A custom ADU will because we’ll design it to be.

Custom ADUs are much more versatile when it comes to design and implementation

Durability And Structural Integrity

Both prefab houses and custom ADUs are durable. However, when it comes to shipping container homes, you have to remember that any hole you make disrupts the structural integrity of the entire construction. Therefore, all changes you want to make (including making holes for windows and doors) must be followed by reinforcing the whole wall. 

Differences Between Custom Build and Prefab Homes

It’s probably becoming quite clear that there are significant differences between custom and prefab ADUs. However, to really help you make a decision on the type of ADU that’s the best choice for you, let’s lay the most important ones out, shall we?

General Appearance

One of the main differences between custom ADUs and prefab container homes is in the appearance. No matter how you spruce it up, a container home will always look like a shipping container made into a tiny house. 

On the other hand, a custom ADU can be made to match the appearance of your main property. It can fit into the overall look of the neighborhood as well. Generally speaking, a container house stands out more than a typical ADU (and not always for the right reasons).


Although both a typical ADU and a container home will prove to be a valuable investment (even if you don’t rent them out), custom ADUs offer more ROI. You can sell them independently or along with your single-family house and increase the overall value of your property.

Generally speaking, the overall ROI on an ADU across the US is around 38%.

Total Building Time and Cost

Cedar ADU: Your One-Stop-Shop for ADUs

The average cost of a custom ADU is around $100 and $500 per square foot, while the average cost of a shipping container home is lower than that. 


Custom ADUs are much more versatile when it comes to design and implementation. Although both prefab and custom ADUs are small, ADUs have better key features and leave you with more room to implement your vision. You have more room to work with in terms of adjusting the design, so it fits your needs.

Ultimately, Pick the Best Fit for You

Depending on what you need and want (as well as what you can afford), you’ll have to pick the best option for yourself. If your property is tricky for shipping container installation, or if your budget is too small for a custom ADU, maybe the choice will be more obvious than in some other cases. 

Alternatively, you can make your own list of pros and cons and make your decision. Either way, Cedar Dwellings will be here to support you!

Cedar ADU: Your One-Stop-Shop for ADUs

Overall, it’s always better to go for the custom option. It allows you to execute your vision better and make any changes and additions you like. In other words, custom designs don’t limit you as much as prefab ones do. 

If you’re looking for a custom ADU that will make for a great:

  • home gym
  • guest house
  • home office
  • mother-in-law suite
  • pool house
  • art studio, etc.

look no further! The Cedar Dwellings team will be more than happy to implement one of our turn-key solutions in your backyard. So book your consultation now, and let’s start making your dream a reality!