A garage is already a building. That is where the savings stop.
On paper a garage conversion is the obvious ADU – walls, roof and slab already there. In practice a garage was built to a completely different standard than a dwelling, and almost every element you can see has to change.
Everything changes except the shape of it.
The slab is the item that surprises people. A garage floor pitched towards the door has to be levelled, insulated and separated from ground moisture before it can be a floor you live on — and depending on how much fall there is, that either means a build-up that costs you ceiling height, or breaking it out and starting again.
Small lots, tight setbacks, and one very useful Arvada rule.
A garage conversion wins where a detached build cannot go: small lots where the setbacks leave nowhere to put a new structure, and Edgewater’s 25-foot lots where the answer is usually up rather than out. It wins again where the garage is already close to services on the main house, because the run is short. We work across Arvada and Edgewater, where lot geometry usually decides this.
Arvada’s 2024 code permits a homeowner to self-build an ADU — which on a garage conversion, where the shell already exists, is the one scenario where that is realistic for a capable owner. We will tell you when that is the better economics for you. We would rather lose the job than sell you work you did not need.
Where it loses: if the garage is detached and far from the house, you are paying for a long service run and a full envelope rebuild, at which point a purpose-built detached ADU on a better part of the plot is usually the stronger asset.
Same state floor, and one thing to check.
A garage conversion ADU is decided the same way as any other — administratively, on objective standards, no public hearing, no owner-occupancy commitment, and 500 to 750 square feet you have to be allowed. Denver extended its lot-coverage exemption to ADUs in the December 2024 rezoning, which matters here because a converted garage already occupies coverage.
The thing to check is parking. Losing a garage means losing a parking space, and while the state removed the requirement to add one, a handful of jurisdictions have not caught up — Centennial still asks for a space, which sits in live tension with the state law. We confirm your city’s current position before design rather than after.
Garage conversion questions we get asked.
Is a garage conversion cheaper than building new?
Sometimes, and less often than people expect. The shell saves you a foundation and a roof; the slab, envelope, services and openings eat most of that back.
Do I lose my parking?
Physically, yes. Legally, the state no longer requires you to replace it in most jurisdictions — but Centennial still asks for a space, so we check.
Can the garage door opening just be filled in?
It becomes a structural wall with windows in it, carrying the load the header used to carry. It is framing and structural work, not a panel.
Can I do some of it myself?
In Arvada, the 2024 code explicitly permits homeowner self-build of an ADU. Elsewhere it depends. We will be straight with you about which parts are worth doing yourself.
Tell us the address. We will tell you what is possible.
We check your zoning, your lot and your city’s current position before anyone draws anything. If the answer is no, you hear it on the phone, not after you have paid for design.
Prefer to talk now? Call (720) 637-2060
Get your free project estimate
A few quick questions on our secure estimate page — about 2 minutes. We call you back the same business day to talk it through.