Garage Conversion or Detached ADU: Which One Makes More Sense?
So, you're standing in your backyard staring at your old garage—aka The Spider Kingdom—and wondering: Should I turn this dusty car cave into an income-generating palace? Or... should I go all-in and build a brand-new Detached ADU (Accessory Dwelling Unit) from scratch?
As construction workers who’ve been on more construction sites than we can count (yes, we’ve lost count after that one backhoe incident), we’ve seen it all. Whether you're a homeowner, investor, or a hopeful custom home builder with dreams of a passive house tucked behind your primary residence, let’s break it down. Which route is better: garage conversion or detached ADU?
The Case for a Garage Conversion
Ah, the classic garage conversion. You already have a structure—walls, roof, maybe even a foundation (hopefully without expansive soils underneath it). So instead of starting from scratch, you're working with a base.
Pros:
Lower Cost – No surprise here. Converting a garage is usually much cheaper than building new. You’ll still need a solid floor plan, GFCI outlets, framing, insulation, and all the works, but you're avoiding major site prep and ready mix concrete pours.
Faster Turnaround – Since you're not waiting on new forms, footers, or foundation work, garage conversions are usually done quicker—less time on the daily report, more time enjoying that rental income.
Less Red Tape – Depending on your city, it may be easier to get permits for a garage conversion than a detached build. Fewer change orders, fewer headaches.
But... the Cons:
Size Limitations – Your garage may only be 400 sqft. That’s cozy. Like, tiny-home-on-wheels cozy.
Design Restrictions – You’re working with an existing shell, so unless you’re ready to pull permits for moving fascia, replacing frieze boards, or pouring new flatwork, your creativity might feel boxed in.
Parking Drama – Some cities still want you to “replace” the lost parking. Yep, that might mean building a carport or shifting your foundation budget.
The Case for a Detached ADU
Ah yes, the construction company dream: blank canvas, fresh dirt, and a new form to fill with possibility.
Pros:
Creative Freedom – With a detached ADU, you can start from your CAD drawing or BIM model and go wild with the floor plan, gable roof, glulam beams, and maybe even a green board-clad deck.
More Privacy – Tenants (or your in-laws) won’t share a wall with your main house. That’s a win-win.
Higher Resale Value – A well-built detached ADU can bump up your property’s value more than a conversion.
Cons:
Higher Cost to Build a House – You're looking at excavation, damp proofing, pouring footings, installing forced air heating, fire-rated walls, and all the goodies that come with building construction from scratch.
Longer Timeline – You’ll be scheduling contractors, waiting on inspections, and dealing with the occasional bid that makes you question reality.
More Permits, More Problems – You’ll need blueprints, zoning approvals, and possibly a visit from someone in a hard hat shaking their head over your grade slope.
So… Which One Makes More Sense?
Honestly? It depends.
If you're looking for the budget-friendly, fast-track route—go with a garage conversion. Especially if your structure’s in decent shape and you don’t mind cozying up a bit. You’ll still get the satisfaction of managing a general contractor, watching the form go in, and maybe even learning what a flashing is (hint: it’s not what it sounds like).
But if your lot can handle it, and you’re in this for the long game—a detached ADU gives you more space, better design flexibility, and future-proof value. Just make sure to pad your budget, because the cost codes on these projects rack up fast.
Pro Tip from the Builders
No matter which option you choose, always work with licensed home builders or a seasoned construction contractor. Someone who knows their way around felt underlayment, has worked with floating slab foundations, and understands how to draft a solid cost-plus contract. Trust us, nothing beats having a reliable crew who shows up, knows their flashing from their fascia, and can handle change orders like a boss.
And remember, this isn't just about building space—it's about building opportunity.
Need help deciding? We’re the construction company you call when you're ready to make it real. Whether it’s a garage turned guesthouse or a brand-new detached oasis, E.H. Construction’s got your back.