Garage Conversion vs. Building New: Which Backyard ADU Is Actually Cheaper in Orlando?

The $130k that was supposed to be $60k

Search "garage conversion cost" and you'll get a number that feels like a steal — somewhere in the $45,000 to $85,000 range for a one-car bay. That number is real. It's also the number for turning a garage into a nicer room. The moment you turn it into a legal, rentable dwelling with a kitchen, a bathroom, a bedroom that meets code, and its own way to get power and water, you're in a different conversation.

So the guy who paid $130,000 for 570 square feet didn't get robbed. He paid for plumbing that had to reach a sewer line that was never run to the garage. He paid for an electrical panel that could carry a second household. He paid to make a slab poured for a Buick into a floor you'd let a tenant's toddler crawl on. The walls and roof were already paid for. Everything that makes it a home was the bill.

Meanwhile a new detached unit of about the same size — say one of the county's pre-drawn plans — lands in the same neighborhood on price, roughly $170,000 all-in in Central Florida for 600 square feet. Not cheap. But look at the gap between that and the conversion, and the whole "conversions save you a fortune" idea gets shaky.

What's hiding under your garage floor

Here's the part that decides everything, and you can't see it from the driveway. A garage floor is built to fail you as a bedroom. It slopes a quarter-inch toward the door so rainwater runs out — smart for a car, a problem for anything with a bed in it. Older slabs in places like Azalea Park or Conway were poured with no moisture barrier under the concrete, because who cared if a garage floor sweated. Put living space on top and code cares a lot. Now you're trenching and sealing that slab or pouring a new one, and there goes fifteen grand before a single wall goes up.

Then look up. A habitable room needs about seven feet of finished ceiling, and you lose four to six inches to a proper subfloor and insulation you didn't have before. So you want somewhere around seven-and-a-half feet of clear height under the trusses just to start. A lot of older Orange County garages don't have it. That one measurement quietly kills more conversions than price ever does.

When a garage does clear those bars — decent height, sewer close by, a slab that's sound — the conversion genuinely is the cheapest legal unit you can build, and nothing else comes close. When two or more of them fail, you're spending new-build money to remodel a building that was never meant for this. That's the actual fork, and it has almost nothing to do with the sticker on either option.

The trade-off nobody puts on the estimate

Say the numbers pencil out and you build the conversion. There's a second bill that shows up years later, at resale. Appraisers around here tend to value a garage-conversion ADU somewhere between $50,000 and $100,000 — often less than you spent building it. So on paper, the day it's done, you can be underwater on the very thing that was supposed to be the smart-money move. A detached unit doesn't erase your garage, so it doesn't ask you to trade one asset for another.

And there's the street itself. In a neighborhood like Rio Pinar or Winter Garden, where every house has a garage and buyers expect one, giving yours up to make an apartment can cost you on the sale even as the rental income helps you now. In a denser pocket of Pine Hills or Meadow Woods where nobody's precious about a garage, that same trade barely registers. The right answer literally changes block to block.

So the real question was never "which one is cheaper." It's "what am I willing to give up, and for how long." Conversion: less yard touched, faster, but you lose the garage and you may sit underwater a while. Detached: more money and more permitting up front, but you keep the garage, you often get a cleaner appraisal, and you're not fighting a fifty-year-old slab the whole way.

How to find out which one your lot wants

None of this is guesswork you have to do alone with a tape measure. Whether you're in the City of Orlando or out in unincorporated Orange County changes your size limits and your parking rules. And if you're in the unincorporated county, the Ready Set Orange program hands you pre-approved plans for detached units in the 530-to-700-square-foot range — the kind that can shave a month or more off permitting and a few thousand off design fees, which quietly narrows the price gap with a conversion even further.

But the plan you should build still comes down to the stuff hiding on your specific lot: your ceiling height, how far your sewer runs, what your street expects, which jurisdiction you're in. That's exactly what the ADU Fit Check is built to sort out. Tell it about your property and it tells you whether your garage is a genuine shortcut or a money pit wearing a bargain sticker — before you've paid anyone to find out the hard way. Start there, and you'll know which of these two projects is actually the cheaper one for you.

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