Garage Conversion or New Construction? What LA Homeowners Actually Need to Know

By Gil Vaisman, Go ADU Construction

If you’re thinking about building an ADU in Los Angeles, you’ve probably already asked yourself: should I convert my garage, or build something new in the backyard?

It seems like a straightforward question. But in our experience, it’s one of the most misunderstood decisions in the entire ADU process — and the answer is almost never what homeowners expect.

Most people assume a garage conversion will be cheaper and faster than new construction, because the structure is already there. That assumption is wrong often enough that we’ve built an entire decision framework around it. And the projects we’ll walk you through in this post — some of which changed course completely mid-planning — are proof of why.

Here’s what this guide covers:

• Why “garage conversion vs. new construction” isn’t really the right question
• What setbacks are, why they matter, and how they actually drive the decision
• The real difference between attached and detached garage conversions
• When conversion makes sense — and when it doesn’t
• Real Go ADU projects that illustrate each scenario, with actual numbers
• A practical decision framework you can apply to your own property

The Question Most Homeowners Are Actually Asking

When homeowners tell us they want a “garage conversion,” what they usually mean is: I want to use my existing garage space rather than build something from scratch, and I expect that to be simpler and cheaper.

Sometimes that’s true. But here’s the reality we’ve learned after building ADUs exclusively in Los Angeles for nearly a decade:

Converting an existing garage can be more expensive and more complicated than building new. Not always. But often enough that the decision deserves a lot more thought than most homeowners give it.

The reason is simple: when you’re working with an existing structure, you’re working with unknowns. You don’t always know what’s inside those walls, how deep the footings go, or what surprises are hiding until you start demo. With new construction, you know exactly what you’re building because you’re building it from scratch. No surprises. No hidden costs. No mid-project decisions you weren’t expecting to make.

So what actually drives the conversion vs. new construction decision? Almost always, it comes down to one thing: setbacks.

What Are Setbacks — And Why Do They Matter So Much?

A setback is the minimum required distance between a structure and the surrounding property lines. In Los Angeles, any new detached ADU must be at least 4 feet from all property lines and typically 6 feet from existing structures on the same lot.

That matters because on smaller LA lots, a 4-foot setback on all sides can meaningfully reduce the footprint of what you can build — and therefore the square footage of your ADU.

Here’s where existing garages have a significant advantage: grandfathered setbacks.

If your garage was built decades ago — before current setback rules were established — it may sit closer to the property line than 4 feet. And if you convert that garage into an ADU rather than demolishing it and building new, you can keep those original setbacks. The city treats it as a conversion of an existing structure rather than new construction.

That can mean the difference between a 500 square foot ADU and a 650 square foot ADU on the same lot. In Los Angeles real estate terms, that’s significant.

The rules around ADU size and setbacks are more nuanced than most homeowners realize — and getting them wrong can cost you significant square footage.

But here’s the catch: to keep those grandfathered setbacks, you have to actually convert the existing structure. You can’t just demolish the garage and build new on the same footprint. The city requires proof that you’re working with the existing structure — typically by preserving at least one original wall.

And that one requirement — preserve one wall — is where things get complicated.

The One Wall Rule: What It Really Means in Practice

In practice, most of our “garage conversions” aren’t really conversions in the traditional sense. We preserve one wall of the existing garage to satisfy the city’s requirement and keep the grandfathered setbacks. Everything else is essentially new construction.

The garage is largely demolished. New foundation work is done. New framing, new electrical, new plumbing, new everything — built to current residential code. The one preserved wall is more of a legal and regulatory strategy than a construction one.

This approach gives homeowners the best of both worlds: the setback advantage of a conversion, with the quality and predictability of new construction.

But it only works if that one wall is actually in good enough condition to preserve. And that’s where projects can go sideways.

The common assumption that garage conversions are simpler and cheaper than new construction — and why that assumption doesn’t always hold up in the real world.

When the Plan Changes: Two Real Projects

Here are two recent Go ADU projects where the original plan was a garage conversion — and we ended up recommending new construction instead.

Curson Avenue, Miracle Mile

This project started as a conversion of an existing detached garage. The lot is tight, so keeping the grandfathered setbacks was important — it would allow the client to build right up to the adjoining property line.

The problem: the existing garage was built in the 1930s. When we assessed the structure, we realized the one wall we needed to preserve wasn’t in repairable condition. On top of that, the grandfathered setback created a roofline problem. Because the structure sat on the property line, it couldn’t increase in height above the original structure at that point — which meant a flat roof for the first several feet before it could rise. That’s a more complicated framing and roofing job, and it drove costs up significantly.

The result: we decided with the homeowner to demo the garage entirely and build a new detached ADU, pulled back slightly from the property line to meet the standard 4-foot setback. They lose a small amount of square footage compared to the original plan — but they get a cleaner build, a better roofline, and no structural surprises.

Elmer Avenue, North Hollywood

This one was even more straightforward. The homeowner has a very large lot — setbacks simply weren’t a concern. We were originally scoping a garage conversion, but the existing structure was old and in poor condition. Retrofitting it offered no real advantage over building new, and introduced all the typical risks of working with an aging structure.

The decision was easy: demo the garage and build a brand new detached ADU. Cleaner, more predictable, and in this case, actually less expensive than a complicated conversion would have been.

Sometimes the best thing you can do with an old garage is start fresh. Here’s what the beginning of a new build actually looks like.

A real example of what can happen when you start working with an existing structure and find something unexpected. This is exactly why we assess existing conditions carefully before committing to a conversion.

When Conversion IS the Right Call: The Strategic Conversion

Now let’s look at the other side — projects where keeping that one wall and preserving the setbacks was absolutely the right decision.

On smaller lots where square footage is at a premium, the strategic conversion approach — demolish almost everything, preserve one wall, build essentially new — gives homeowners access to more buildable space than new construction would allow. The result is a unit that’s larger, more valuable, and more livable.

Three recent examples:

Placidia Avenue, North Hollywood

On this project, the existing garage sat close to the property line. By preserving one wall and keeping the grandfathered setbacks, we were able to build a significantly larger unit than a fully new detached ADU would have allowed. We demolished most of the existing structure and built essentially new — with one original wall retained for regulatory purposes. We also added new square footage beyond the original garage footprint, with that addition conforming to the standard 4-foot setback.

The Placidia homeowner talks about the rental performance and what the process was like — from first conversation to first tenant.

Ridgeley Drive, Miracle Mile

Same approach on a tight lot in Miracle Mile. The existing garage sat close to the adjoining property, and the homeowner wanted a unit that matched the 1920s Spanish character of the main house. By preserving the setbacks through the strategic conversion approach, we maximized the buildable footprint and gave the architect room to create something genuinely special.

A walkthrough of the finished Ridgeley Drive ADU — custom design, premium finishes, and a result that fits the neighborhood beautifully.

Moore Street, West Los Angeles

A two-bedroom unit on a desirable West LA property. Same strategic conversion approach — one wall preserved, setbacks maintained, essentially new construction from there. The client, a young professional who couldn’t afford to buy in the neighborhood, built this as her primary residence on her mother’s property.

Step inside the Moore Street two-bedroom — 675 square feet with 12-foot ceilings, built as a primary residence in one of LA’s most desirable neighborhoods.

One important note on adding square footage to a conversion: when you build beyond the original garage footprint, the new square footage must conform to current setback requirements — typically 4 feet from property lines. Only the portion within the original footprint keeps the grandfathered setback. We plan for this from the start so there are no surprises during permitting.

Bellflower Boulevard

This project illustrates the strategic conversion approach on an older property that had been in the family for a generation. The existing garage was old, but the lot conditions made preserving the setbacks worthwhile. We kept one wall, demolished the rest, and built a two-story, two-bathroom ADU that more than doubled the original square footage.

Strategic Conversion: Calzona Street — Building Generational Wealth

Before we move to attached conversions, one more strategic conversion worth highlighting — because the story behind it is one of our favorites.

Our clients on Calzona Street were a young couple with a clear goal: create a source of passive income on their property and start building generational wealth for their family. Their existing detached garage was the obvious candidate, and the lot conditions made preserving the setbacks worthwhile — so we kept one wall and built essentially new from there.

The project was clean and straightforward. No major surprises. The finished unit is a well-designed one-bedroom rental that started generating income immediately.

A look inside the finished Calzona Street ADU — a one-bedroom rental built to generate passive income and long-term wealth for a young LA family.

The Calzona homeowners talk about their goal of building generational wealth through their ADU — and what the experience of working with Go ADU was like.

Attached Garage Conversions: A Different Animal Entirely

Everything we’ve discussed so far applies to detached garages. Attached garages — spaces connected directly to the main house — work differently.

With an attached conversion, the setback question usually doesn’t apply in the same way, because the structure is already part of the main house. You’re not choosing between conversion and new detached construction — you’re working with what you have. The question becomes how to transform an existing attached space into livable, code-compliant residential square footage as efficiently as possible.

Attached conversions have their own set of complexities. Fire separation between the ADU and the main dwelling is required by code. Egress — meaning safe exit routes — needs to be carefully planned. Structural integration with the existing house requires attention. And like any conversion, you may encounter surprises once demo begins.

Fire separation between an attached ADU and the main house isn’t optional — here’s what it involves and why it matters.

Two Go ADU projects illustrate how attached conversions work in practice — and the very different ways homeowners can put them to work.

Santa Clarita — The Airbnb Success Story

This is one of the most compelling ADU investment stories we’ve been part of.

Our Santa Clarita clients converted their attached garage into a studio ADU with one specific goal: generate short-term rental income on Airbnb. They financed the build using their home’s equity — and within the first 30 days of listing, the rental income was already covering the loan payment.

By the end of that first month, the property was booked out four months in advance.

That’s not a fluke — it’s the result of a well-designed space in the right location, built for the right purpose from the start. The unit was conceived as a rental property, designed accordingly, and marketed intelligently. The financial result speaks for itself.

A walkthrough of the Santa Clarita studio — designed specifically for short-term rental and booked four months out within its first month on Airbnb.

The Santa Clarita homeowners share how they financed the build, how quickly it started performing, and what it’s like having a thriving Airbnb in their backyard.

Grambling Place, Carson — The Mid-Term Rental Strategy

This is one of our earlier projects, and it remains one of our favorite rental success stories. Our client converted her attached garage into an ADU and immediately began renting it as a mid-term rental — primarily to traveling nurses and other healthcare professionals working temporary assignments in the area.

The result: continuously rented since month one, at rates significantly above typical long-term rental income for the area. Mid-term rentals — generally 30 days to 6 months — can command premium rates while avoiding the complexity of nightly short-term management. For the right homeowner in the right location, it’s one of the most effective ADU rental strategies available.

A walkthrough of the Grambling Place ADU in Carson — a mid-term rental that’s been continuously occupied since the day it was listed.

Hear from the Grambling Place homeowner about her mid-term rental strategy, her experience with Go ADU, and how the ADU has performed since completion.

The Decision Framework: Which Path Is Right for Your Property?

Based on everything above, here’s a practical framework for thinking through the conversion vs. new construction decision on your own property.

Step 1: Do you have a detached garage?
If yes, move to Step 2.
If no (attached garage or other connected space), you’re likely looking at an attached conversion. See the attached conversion section above.

Step 2: How big is your lot — and do you need the setbacks?
If your lot is tight and maximizing square footage matters, preserving grandfathered setbacks through a strategic conversion may give you significantly more buildable space. Move to Step 3.
If your lot is large and setbacks aren’t a constraint, new construction is likely simpler, more predictable, and potentially less expensive. Skip to Step 5.

Step 3: Is the existing structure in repairable condition?
If yes — at least one wall is structurally sound and can be preserved — a strategic conversion is likely viable. Move to Step 4.
If no — the structure is too deteriorated to preserve — new construction may be your only practical option regardless of lot size. Move to Step 5.

Step 4: Are there any roofline or height complications from the existing setback?
If the existing structure sits on or very close to the property line, check whether height restrictions apply to that portion of the structure. If they do and they significantly limit your design options, weigh the setback benefit against the design constraint. Sometimes the constraint isn’t worth it.

Step 5: New construction.
Demo the existing structure and build new. You get a clean slate, predictable costs, no hidden surprises, and full design flexibility within current setback requirements.

What new construction actually looks like from day one — clean, planned, and built exactly as designed.

What About Cost? Conversion vs. New Construction

Here’s the honest answer: the cost difference between a strategic conversion and new construction is often smaller than people expect — and sometimes conversion costs more.

When you factor in demolition of the existing structure (which happens in both cases on a strategic conversion), the cost of working around existing conditions, and any surprises inside old walls or foundations, the savings from “reusing” an existing structure can evaporate quickly.

Here’s how our recent projects compare:

The takeaway: cost per square foot is driven more by size, design complexity, and site conditions than by whether the project is technically a conversion or new construction. Don’t choose conversion because you think it will automatically be cheaper — choose it because it’s the right approach for your lot and your goals.

Why fixating on cost per square foot can lead you to make the wrong decision — and what to focus on instead.

A deeper look at why cost per square foot can be a misleading metric — and what you should really be evaluating when planning your ADU investment.

A Note on Rental Income

Across our projects, ADUs built for rental purposes have consistently performed well in the Los Angeles market — regardless of whether they were conversions or new construction. What drives rental performance is design, location, and finish quality — not how the unit was built.

Short-term, mid-term, or long-term rental — each strategy has different income potential and management requirements. Here’s how to think through the choice.

So Which Is Right for You?

The honest answer is: it depends on your property, your lot size, the condition of your existing structure, and what you’re trying to accomplish.

What we’ve learned from building ADUs exclusively in Los Angeles for nearly a decade is that the homeowners who get the best results are the ones who start with an honest assessment of their property — not an assumption about what path they should take.

We’ve changed course mid-planning more than once when the facts on the ground didn’t support the original approach. That’s not a failure — that’s good planning. And it’s the kind of flexibility that comes from working with a builder who’s seen enough projects to know when to adapt.

If you’re trying to figure out which path makes sense for your property, the best first step is a real conversation — not a quote, not a bid, just an honest look at what you’ve got and what’s possible.

Schedule Your Free Consultation →

Frequently Asked Questions

Is a garage conversion always cheaper than building a new ADU?

No — and this is one of the most common misconceptions we encounter. Converting an existing garage involves working with unknown conditions inside old walls and foundations, which can drive costs up significantly. New construction is more predictable because everything is built from scratch to a known standard. The cost difference between a well-executed strategic conversion and new construction is often smaller than people expect.

What is a “strategic conversion” and why do you use that approach?

A strategic conversion is our term for a project where we preserve one wall of the existing garage to maintain grandfathered setbacks, while demolishing and rebuilding everything else to current residential standards. It’s a regulatory strategy as much as a construction one — it gives homeowners access to more buildable space on tight lots while delivering essentially the quality of new construction.

What are grandfathered setbacks and why do they matter?

Grandfathered setbacks are the original property line distances that applied when your garage was built, which may be closer to the property line than current rules allow. By converting rather than demolishing, you can keep those original setbacks — which can mean significantly more square footage on smaller LA lots. Any new square footage added beyond the original footprint must still conform to current 4-foot setback requirements.

What happens if the existing structure isn’t repairable?

If the wall we need to preserve isn’t in good enough condition to retain — as happened on our Curson Avenue and Elmer Avenue projects — conversion may not be a viable option. In those cases, new construction is typically the cleaner and more cost-effective path, even if it means losing some square footage due to current setback requirements.

How are attached garage conversions different from detached?

With an attached conversion, the setback question usually doesn’t apply — you’re working with an existing connected structure and transforming it into livable space. The focus shifts to fire separation between the ADU and main dwelling, egress planning, and structural integration. Attached conversions have their own set of complexities but are a well-established path to adding an ADU when a detached option isn’t available or practical.

Can I use my ADU as a short-term, mid-term, or long-term rental?

Yes — and the right strategy depends on your location, your lifestyle, and how involved you want to be in managing the property. Short-term rentals (Airbnb) can generate the highest nightly rates but require active management. Mid-term rentals (30 days to 6 months) attract traveling professionals and can command premium rates with less turnover. Long-term rentals offer stability and passive income with minimal day-to-day involvement. We’ve seen all three strategies work well for our clients across Los Angeles.

How much can I rent my ADU for in Los Angeles?

It varies significantly by neighborhood, ADU size, and rental strategy. From our recent projects: long-term rentals have generated $2,200–$2,700/month, and mid-term rentals have reached $2,700–$3,000/month. Short-term rentals vary more widely depending on location and season. In all cases, design quality and finish level have a significant impact on achievable rents.

Do I need a permit to convert my garage into an ADU?

Yes — all ADU construction in Los Angeles requires permits, regardless of whether it’s a conversion or new construction. The permitting process involves architectural plans, engineering, city plan check, and multiple inspections. [Internal link placeholder — Steven will add link to ADU permitting guide once that post is published.]

What’s the first step if I want to explore building an ADU?

The most useful first step is an honest assessment of your property — lot size, existing structures, setback conditions, and your goals. That conversation is free and it’s what we do at the start of every project. It’s also how you avoid spending months planning an approach that doesn’t actually work for your site.

Schedule Your Free Consultation →

About Go ADU Construction

Go ADU Construction is a family-owned ADU builder based in Burbank, CA, serving the greater Los Angeles area since 2017. We specialize exclusively in ADU design, permitting, and construction — and we handle every stage of the process so you don’t have to. License No. #1076712.