Types of ADUs | Which ADU is Best for You?

Types of ADUs | Which ADU is Best for You?

Different Types of ADUs | Breaking Down the Pros and Cons

Have you ever wondered which type of accessory dwelling unit is the perfect choice for your property? If you did, you’re not alone. Even though the ADU craze has been sweeping California ever since both the government and the residents figured out they could solve the affordable housing crisis, people still aren’t fully aware of which options they have.

ADUs can be separate from your primary dwelling, or they can be built within your single-family home. Either way, they’ll add value to your home

A One-Stop Solution in the form of a Backyard Cottage Revolution

ADUs allow affluent, job-rich neighborhoods to increase housing options without changing the existing structure. These tiny houses are the perfect solution for the lack of affordable housing. For example, renting an ADU in California costs around $3.86 per square foot. That means that people can rent an ADU in someone’s backyard for around $2,000. 

The rent is a bit steeper in the San Francisco Bay Area or the Los Angeles Area (around $2,200), which is a steal compared to the rental prices of houses and apartments. Let’s not forget that even though the rent prices dropped post-COVID, the average rent in SanFran is still relatively high (around $3,280 for a one-bedroom apartment). Things are pretty much the same in LA, where a one-bedroom apartment will cost you around $2,000 and $3,000, depending on where you want to live.

So, no matter how we look at it, ADUs are the solution to affordable housing. If you rent one, you can have a fully functional living space for less money. On the other hand, if you own one, you can become a landlord and get some rental income.

Becoming a landlord isn’t easy, as we already discussed. However, an ADU project can make it easier for you to get that extra income. All you have to do is figure out which type of ADU is the best choice for you and build it. Piece of cake, right?

different types of adus

Different Types of ADUs

By definition, an ADU is a separate dwelling unit that’s completely separate from the primary residence in terms of facilities and entires. So, it’s an independent unit that has very little to do with the primary housing unit. It might share a wall or two with it (or all of them), but other than that, granny flats house very independent grannies (or non-grannies).

If you’re looking to expand your living space with an ADU, know that there are several different types of ADUs that are available to you. The most common types of ADUs are:

  • Detached ADUs are entirely separate units built away from the primary residence.
  • Attached ADUs share a wall or two with the primary residence but are newly built constructions.
  • Interior conversion ADUs or JADUs are newly created living units within the walls of the primary residence. Interior ADUs usually don’t go over 500 square feet.
  • Exterior conversion ADUs — garage conversions as well as attic and basement conversions.

Many people think that they can’t build an ADU because they don’t have enough backyard space. Clearly, that’s not an issue. 

However, not all ADUs are made equal. Each type of ADU has its own pros and cons; let’s see what they are.

pros and cons of adus

ADUs vs. JADUs

Generally speaking, there are only two different types of ADUs — standard ADUs and junior ADUs or JADUs. A standard ADU is built by creating a new space that’s separate from the primary residence and can be either attached or detached. 

JADUs, on the other hand, include converting existing space within the primary unit into a new, separate living unit. The most common JADUs are garage conversions, although basement conversions and attic conversions are also becoming quite the hit lately.

If you’re building a standard ADU (be it a detached or an attached ADU), you have several pros to look forward to:

  • You’re creating a new space that you can decorate however you like.
  • Renting them out is much easier.
  • They won’t be as disruptive to your life as some other types of ADUs
  • They don’t take away from your existing storage space (like a basement or attic) or parking space (like a garage).

However, they do have some cons to them:

Although JADUs might seem like a less desirable option, they also have some pros to them:

  • You’re capitalizing on existing space (that you might not even be using).
  • They aren’t as expensive to build.

However, JADUs do have significant drawbacks:

  • An interior ADU doesn’t provide extra space; it just repurposes the space you already have.
  • They take away your storage and/or garage space.
  • They aren’t as private.

The Pros and Cons of Different Types of ADUs

Because ADUs come in all shapes and sizes, it’s essential to know which exact type is the best fit for you. Building and furnishing an ADU can cost you anywhere from $100,000 to $400,000, so before you sink that money into a project, you must plan it diligently and to the very last detail. And that includes deciding which type of an ADU to build.

Detached ADUs

Detached ADUs are among the most popular in California. They have plenty of pros to them that usually sway people into starting a detached ADU project. 

These ADUs are completely separate living units. They don’t share any walls with the primary residence, and they have their facilities, utilities, and entrances. When people talk about backyard cottages and granny flats, they usually envision detached ADUs. 

The Pros

Because there are no shared walls between the two residences (in fact, there’s quite a bit of yard space between them), detached ADUs offer the best privacy. They are the ideal choice for those who are building an ADU to rent it.

Having tenants in your detached ADU will keep the disruption of your life to a minimum. That’s especially true if you have a big backyard. However, it will also make it easier for you to rent it out. 

If you’re building an ADU intending to rent it to strangers (as opposed to inviting family members to live in it), a detached ADU is a perfect choice. After all, you can’t exactly share your space with just anyone.

The Cons

To build a detached ADU, you need space. If you have it, then you’re golden. However, you might also need (quite a bit of) money. Detached ADUs are the most expensive to build. Furthermore, they require you to install separate utility lines (or update your current ones), and, depending on where you live, you might also need to fulfill some parking requirements (as per Senate Bill 1069).

Attached ADUs

The attached ADUs are still separate from the main house in terms of utilities and facilities, but they do share a wall or a few with the main unit. 

People who opt for attached ADUs usually use them as living spaces for family and relatives (such as boomerang kids or elderly in-laws) or as extra office space. During this past year and a half, we’ve all seen just how precious separate working space can be. So, it’s no wonder that many homeowners are opting to build an attached ADU that they’ll turn into a modern, stylish, and, more importantly, quiet and secluded office.

what type of adu is best for you

The Pros

After detached ADUs, attached ADUs offer the most privacy. What’s more, they aren’t as extensive of a project as detached ADUs because you can piggyback off of your existing utility systems (such as plumbing and electric). 

Not to mention, they are a bit cheaper than their detached brethren. 

The Cons

Although cheaper, attached ADUs can still be costly. Not to mention, you still need to have extra land to build one. So, if you have a tiny backyard, an attached ADU won’t necessarily be a better choice than a detached one.

Interior Conversion ADUs

Interior conversions are the easiest for people who have more living space than they need. Single-family homes can sometimes be huge, which is why converting a part of that space into a separate living unit might be a good (financial) idea.

The Pros

Interior conversions aren’t as costly as building a separate living unit. You already have pretty much everything you need — the walls, the floors, and maybe even a bathroom. Most importantly, you have the utilities in place. So, with a bit of construction magic, you can have a home within a home in a matter of weeks.

The Cons

Privacy is severely limited with interior ADUs. You’d have other people living within your space and, no matter how much you try, you’ll always know they are there. That’s why interior conversions are more suited for people looking to move in family members.

Exterior Conversion ADUs

Exterior conversions include garage, above the garage, and basement and attic conversions. 


The Pros

With an exterior conversion, you’re capitalizing on existing space without minimizing your current living space. Exterior conversions provide more privacy than interior ones, given that they usually have a separate entry.

Exterior conversions are that sweet spot between money and value. They generally aren’t expensive and, short of standard ADUs, offer the most privacy.

The Cons

Even though the project won’t cost you as much as a separate ADU, it will still cost more than converting interior space. So, it’s still a significant investment. If you really don’t have the yard space for a separate, detached ADU, then a garage or basement conversion might be the best choice. However, if you do, it’s better to spend a bit more money and reap the benefits a standalone ADU offers.

Types of ADUs | Build the ADU of Your Dreams With Cedar

Overall, if you have the space (and the money), a detached ADU is the best choice. But, building one will take time, effort, and money, which is why the Cedar team is here! Because we’re intimately familiar with the pros and cons of all types of ADUs, we always work extra hard to ensure our clients get the ADU that’s perfect for them.

If you’re unsure of which direction to take our ADU design, we can help. However, because we provide a full experience, the Cedar team also offers:

  • minimization of construction noise 
  • help with financing
  • ADU renter help
  • ultimately adding value to your home

So book your appointment today and start your glorious ADU journey!