Building An ADU In California Isn’t Easy

My wife and I are building an ADU at our new primary residence here in California’s Central Coast. 

We are officially through the planning phase of our ADU build now that we received final plan approval from the city on November 21st. 

So it felt like now would be a great time to take a step back and look at what it’s taken for us to get this far. 

It’s a milestone!

The actual ADU build planning phase started in late January of this year. That’s when we had our first in-person meeting with our architect.

Side note: nothing makes you feel like you’re adulting more than meeting with “your architect”.

All told, it’s been about 10-months of planning.

Oof!

Needless to say, planning our ADU build has been a journey.

And I’m here to tell you all about it, what we’ve learned, things you need to consider, and how we navigated it all.

Buckle up!

Building An ADU Doesn’t Require A Real Estate Background But…

First, a note about doing a build like this in the first place.

You do not NEED a real estate investing background if you want to build an ADU.

But here’s the thing… It helps a ton!

My wife and I have been investing in real estate since 2019.

And I don’t mean just buying something with a tenant, collecting rent, and chilling.

We definitely did some stuff like that, but we quickly started doing lots of stuff like this:

And we’d done our fair share of tearing apart our primary residence and doing the work ourselves too.

All this to say that having some experience with real estate and remodeling definitely gives us a leg up over the average ADU journeyperson.

And that experience gives us the confidence to do two things.

First, we’re tackling a more ambitious ADU project than most people. I’ll talk more about that later.

Second, we’re having our builder “white box” our ADU build so we can save a boatload of money by doing the finishes ourselves. 

I wrote a lot more about how we’re going about our ADU build and the investment numbers we expect in this earlier post. 

It’s definitely worth a read!

And I’m sure I’ll look back at that and chuckle about how ambitious we were about the costs.

I digress. Back to planning our ADU and what that looks like…

There Are Two ADU Paths You Can Take

ADU popularity has been growing quickly, especially in higher cost of living markets like California.

As a result, laws are rapidly changing to favor quicker permit turnaround times, greater allowances for ADU heights and setbacks, and a bunch of other stuff.

But this post isn’t about ADU laws, and I don’t want to pretend I’m an expert on all that. We heavily leaned on our architect for that knowledge. 

The point is, it’s becoming increasingly easier to build an ADU. In fact, many cities have streamlined the planning process a great deal.

Pre-Approved ADU Plans From Your City

Most cities, at least in California, seem to have pre-approved ADU plans. 

That means you don’t have to go out and hire an architect and muddle through the costly process of designing from scratch.

Pre-approved plans are also great because it grossly speeds up your ADU planning timeframe. 

It’s a smart option for folks that just want to get moving as quickly and cost effectively as possible. So if you’re looking to go this route just Google your city followed by “pre-approved ADU plans” and you will hopefully get something.

Here’s a cute little studio ADU from our city website here in Arroyo Grande:

So why didn’t we go this route with our ADU build?

I’m glad you asked!

Choosing To Custom Build Our ADU

Most pre-approved city plans are relatively limited. 

It may be easy to change small things like window placements, interior layouts, etc. But doing so will likely incur added costs as well. 

Regardless, the big limitation to pre-approved ADU plans seems to be the size and placement of the structure. 

While a city like Los Angeles appears to have a great selection of pre-approved ADU plans, our smaller town on the Central Coast doesn’t have many.

Even still, you’ll notice that the square footage options on most of these ADU’s are under 500 square feet. The other big factor is that most (all?) of these pre-approved ADU plans seem to be for detached ADU’s. 

Our thought process was two-fold. 

First, we did not want to eat up our yard space with a detached ADU. We have two young, rambunctious boys and we like having space for them to play. While we do have a large lot (10,500 square ft), we wanted to retain our yard.

Second, we figured if we were doing this we were DOING this. We wanted to create an ADU that made sense for us both in terms of size, customization, and placement.

Our ADU build plan, therefore, is far more involved. 

We are tearing down our garage, rebuilding it with an expanded footprint, and building our ADU as a 2-bedroom, 1-bath unit above the new garage (and a sick balcony to boot!).

Sounds expensive, right? And time consuming, yeah?

Subscribe to my weekly newsletter and I’ll let you know when the next ADU post goes live breaking down how long each of these processes took and what the total costs have been:

Now that you know your options, let’s understand what’s needed to take on a more ambitious ADU build rather than a pre-approved plan.

And let’s see if I can talk you out of doing the same! (I kid… but not really).

Key People Needed While Building An ADU

Before you start thinking about who exactly you’re going to need for building your ADU you’re going to have to decide if you will rely on a general contractor.

Yep, that’s right… more decisions to make decisions!

For many folks this won’t even be a question. 

But if, like us, you have some real estate experience, you may be wondering if you should just manage the process yourself.

Acting As Your Own General Contractor

That’s exactly the boat we found ourselves in. Again, we have some pretty solid experience managing subcontractors and trades people for residential renovations.

If you’re highly organized, good at keeping folks accountable, and understand the process, this can be a great way to go.

You’re basically cutting out the middleman and you SHOULD be saving money.

Sounds great, right? 

So why did we decide to use a general contractor instead of rolling the process ourselves?

Using A General Contractor While Building An ADU

People generally use a general contractor for two reasons: convenience and knowledge. Most people simply don’t understand general construction and find it quite intimidating. 

It’s nice to have an expert take the reins and be responsible for the entire process end-to-end.

For us it wasn’t so much about convenience. We’re happy to take the responsibility especially if it’s going to save us a ton of money.

But here’s the thing…

We Don’t Actually Have New Construction Knowledge

The biggest reason we decided to leverage a local builder was because we’ve simply never done ground-up construction.

Yes, we’ve torn houses apart. 

Yes, we’ve done some foundation repairs and fixes. 

And we’ve put all these things back together.

But we felt very much out of our wheelhouse when talking about starting from scratch. 

And while we had a pretty good idea about the order of operations, we simply didn’t feel confident enough to run the process ourselves.

To save some headaches, and potentially costly mistakes, we were happy to find a builder we liked.

But it’s also likely that hiring a general contractor could actually save us time and money.

Convenience & Cost Effectiveness With A General Contractor

A lot of people think about a general contractor’s margins and dream of all the money they could save if they were able to simply do it themselves.

This can be a mistake, especially if you’re in uncharted territory.

General contractors have a ton of experience you don’t. That’s not just about general construction knowledge. It also comes into play when working with subcontractors.

A good general contractor has a bunch of experience and contacts. They know who does good work, who is overpriced, who does shoddy work, etc.

Often, this experience will SAVE you money even when accounting for the general contractor’s margin.

We have been through the process of learning hard lessons. Hiring the wrong people can easily cost you double would it should have cost you to hire the RIGHT people the first time.

I am more than happy to pay this “tuition” today in an effort to gain experience and some potential contacts for future projects.

For these reasons we decided to work with a builder. 

But we are staying extremely involved in the process to learn as much as possible. We’re also doing a cost-plus contract with our builder to provide even more transparency and learning.

Now that you’ve decided to look for a builder, or decided to be your own general contractor, there are other folks you’ll need for your ADU team.

Finding An Architect For Our ADU Build

Your ADU architect is arguably the most important person on your team.

Why?

An experienced architect will intimately understand local laws, rules, and regulations.

If they’ve been active in your area with other ADU projects they likely also have some rapport with city officials.

All of this can be invaluable, especially when the city tries to screw you on plan check and permit fees (yes, there’s a story here).

The right architect should save you time when it comes to plan checks and getting your permits. And, if things go wrong, they may know who you need to complain to to make them right!

Our ADU architect was actually the first person we found and hired. Yes, even before our builder!

So How Do You Find An ADU Architect?

Personally, I’d avoid mindlessly searching the Internet for your ADU architect.

Yes, you may find a good fit, but you have just as good of a shot at finding someone that simply threw some advertising dollars at the interwebs and may not be ideal (to put it lightly).

We found ours through a direct referral.

I was walking my dog and noticed a garage being torn down. I stopped the crew and asked what was going on.

When I found out they were building an ADU I first congratulated myself on an accurate hunch and then took down their info.

A couple months later, after watching the progress, we reached out. 

The general contractor for that project actually ended up giving us the contact information of the architect on the job.

He didn’t even want to talk about bidding for our project until we had preliminary architectural plans (in hindsight this makes a ton of sense). 

So we reached out to the architect, liked her, and felt her pricing was reasonable.

It definitely helped that she was doing a project right down the street, and she clearly understood city requirements and processes.

If you don’t stumble across an in-process ADU near your house I’d highly recommend doing some outreach in your local neighborhood Facebook group. 

We’ve found a lot of great recommendations and first-hand experiences that way. In fact, that’s ultimately how we found our builder!

Working With A Structural Engineer For Your ADU Planning

If you’re taking on a project like ours where you’re tearing down a garage, rebuilding, and adding a second story ADU, you will likely require a structural engineer.

Why?

Chances are the slab your garage sits on is not equipped to handle the extra weight of a second story.

In fact, our primary home is a one-story structure. So it’s unlikely any part of the house can support a second story addition.

This baby does not look built to hold a second story addition:

This is where things get completely out of scope for an architect and you’ll have to bring in a structural engineer. 

Their job is to (as far as I understand it) do all the math and make sure that the structure you’re trying to build can be safely and properly supported.

Chances are, in your foundation’s current form, it can’t. 

So the structural engineer will have recommendations that include tearing out your garage’s foundation and redoing it, or something less involved (and more cost effective) like expanding existing footings.

However, the structural engineer can’t do her job until she understands what kind of soil the structure is sitting on.

Hiring A Soil Testing Company

Yep, ANOTHER person you need to get involved!

Luckily, this one is pretty straight forward. Testing soil isn’t really something you can screw up so we simply called a handful of folks we found on Google and went with the most reasonable and responsive company.

We didn’t know what to expect.

I had visions of some sort of big machine that was going to drill down and take a core sample as if we were prospecting for gold.

Something like this bad boy seemed equal parts overkill and plausible:

Nope.

Some dude showed up with what I can only describe as a garden shovel and bag, spent about 3 minutes in our backyard, and was off.

Talk about anticlimactic!

Once the soils report is done and processed your structural engineer can do her job.

Then it’s about getting everything packaged up and submitted to the city for approval to get started on construction.

That’s Your Core ADU Team!

Congrats! You now know what it takes to put a team together for a custom ADU build: an architect, builder, and structural engineer. Everything else is about finding subcontractors and other one-off folks like our soils testing company. 

We did end up having to find a solar installation company as well but I’ll touch on that in an upcoming post that details how long each of these components took and how much we’ve spent so far.

For now, just know that these are your core three people to get you through the planning and permitting phase.

How about you? Are you building an ADU or planning to build one?

Does this experience sound normal? Scary?

Let me know in the comments and I’ll be happy to help where I can!