Garage conversion vs. detached ADU: what Title 24 sees differently.
Both need a CF1R. What differs is how each one gets classified — and that classification is what decides whether solar is on the table.
New construction vs. alteration is the whole distinction
Both a garage conversion and a new detached ADU need a Title 24 report — that part doesn’t change. What differs is the classification underneath: a newly built detached ADU is generally treated as new construction, while a garage conversion is generally treated as an alteration to an existing structure that’s becoming conditioned space. That one distinction is what drives most of the practical differences.
Solar is the biggest one. New construction generally carries the solar PV mandate (see does my ADU need solar for the exceptions). A garage conversion, classified as an alteration, is generally exempt from that same-construction PV requirement — the existing roof and structure aren’t being newly built, they’re being repurposed.
Envelope and HVAC requirements apply to both, just measured differently. A detached ADU’s whole envelope is new, so the whole thing gets modeled against current standards. A garage conversion’s existing walls, roof, and slab are evaluated as part of an alteration — what has to be upgraded depends on what’s already there and what’s changing, not a blank-slate model. Either way, if the project also involves an HVAC change-out or new ductwork, that gets modeled specifically.
Neither path is inherently cheaper or slower on T24 Studio’s flat rate card — both are priced the same way under 3,000 square feet. The difference shows up in what the model has to account for, not in what you pay.
Prices
Flat fees, in writing before I start. No hourly, no bid package, no change-order games — the number on the quote is the number on the invoice.
Your first report with me
One per client, homes under 3,000 square feet. Full energy model, CF1R and CHEERS registration. It’s a test run — send one job and see how it goes.
Every model after the first
The standard rate once you’re a client — the second building, ADU plus main house, the next project that walks in. Back in 3 business days.
Over 3,000 square feet
Quoted from the plans before any work starts, same day.
24×36 plan-sheet set
Your CF1R laid out full size, matched to your drawing set. Comes back as a PDF you drop straight in.
Revisions
Two revisions included, plus questions any time. Past two I quote first, before I touch it.
Commercial / tenant improvement
Send the plans and you’ll have a flat quote back the same day. No deposit, no minimum.
How it works
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01
Send the plans
A PDF of the architecturals and the project address. If something’s missing I ask once, in one email — not five.
Mechanical and plumbing don’t have to be picked yet. If the plans don’t call out the HVAC or the water heater, I model what I’d normally specify for that job and tell you exactly what I assumed. Change any of it and I’ll rerun — that’s not a revision.
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02
I build the model
If the design does not comply as drawn, I tell you what the model needs to pass and the least disruptive way I can find to get there — your call what goes on the drawings.
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03
You get it back ready to sign
CF1R registered with CHEERS, you named as the responsible designer. 3 business days — 24–48 hours on your first one. Pay on delivery: Zelle, Venmo or Cash App.
One honest note
I’m not a licensed engineer or architect, and I don’t stamp drawings. On the CF1R I’m the documentation author — you stay the responsible designer. Nothing about your role on the job changes.
That’s on purpose. I’m not after your scope or your clients. I do one piece of the permit set — the piece that usually holds it up — and I do it fast.
Garage conversion & ADU classification questions
If yours isn’t here, see the full FAQ or call and ask.
Does my ADU or addition actually need one?
Almost certainly. New conditioned floor area — ADUs, JADUs, garage conversions, additions — triggers Title 24. So do alterations that touch the envelope, the ductwork, or the HVAC equipment, including a straight change-out. A remodel that only moves non-structural interior partitions usually doesn’t.
Send it either way. If it doesn’t need a report I’ll say so and there’s no charge for the look.
Is a garage conversion faster to get through Title 24 than a new ADU?
Does an attached ADU (not detached, not a garage conversion) follow the same rules as a garage conversion?
Not sure which one your project is?
Send the plans either way — the classification, the solar answer, and the report all come back together.