How to Choose an ADU Contractor in Colorado (Questions to Ask)
How to hire an ADU contractor in Colorado, the questions to ask, the red flags to avoid, how licensing works here, and modular versus site-built compared.
Center’s real rules, taxes and rents — read from the codified ordinance, every figure sourced and dated. Here: a HUD benchmark rent of $797/mo for a 1-bed. Run your own numbers below, free.
Read from the Center Code Of Ordinances itself — the operative legal text, not a website summary.
| Maximum ADU size | 750 sq ft for a detached ADU; an ADU built into a single-family house may be up to 30% of the house's floor area or 750 sq ft, whichever is larger, or a whole basement or garden levelverified October 2026Center Code Of Ordinances §44-73the ordinance text(f) Detached Accessory dwelling units. If the accessory dwelling unit is detached from the primary dwelling unit on the property, the floor area of the accessory dwelling unit may not be more than seven hundred and fifty (750) square feet. | (h) Integrated units. In single-family dwellings, an accessory unit may be integrated into the principal building. The floor area of the integrated accessory dwelling unit may not be more than thirty (30) percent of the floor area of the principal building, or 750 square feet, whichever is larger, except that an integrated accessory dwelling unit may occupy an entire basement or garden level, regardless of floor area. |
| Size relative to the main house | 30% of the house's floor area or 750 sq ft, whichever is larger (ADUs built into a single-family house); no limit for a whole basement or garden levelverified October 2026Center Code Of Ordinances §44-73the ordinance text(h) Integrated units. In single-family dwellings, an accessory unit may be integrated into the principal building. The floor area of the integrated accessory dwelling unit may not be more than thirty (30) percent of the floor area of the principal building, or 750 square feet, whichever is larger, except that an integrated accessory dwelling unit may occupy an entire basement or garden level, regardless of floor area. |
| Owner occupancy | No — no owner-occupancy requirement (the ADU and the main house must stay in undivided ownership)verified October 2026Center Code Of Ordinances §44-73the ordinance text(e) The accessory dwelling unit must be owned together with the principal residential unit in undivided ownership. | Sec. 44-73.1(e) asks only for proof of property ownership or owner authorization; no part of Sec. 44-73 or 44-73.1 requires the owner to live on the property. |
| Short-term rental | No — rentals on a property with an ADU must be at least 90 days by written lease (Sec. 44-73(d))verified October 2026Center Code Of Ordinances §44-73the ordinance text(d) If any of the dwelling units are rented, a minimum of a 90-day rental period shall be required by written lease. |
Source: Center Code Of Ordinances, §44-73 · ordinance text retrieved 2026-10-22, re-verified October 2026 · open “the ordinance text” under any figure to read the exact sentence it comes from.
Center’s size cap is conditional rather than a single number: 750 sq ft for a detached ADU; an ADU built into a single-family house may be up to 30% of the house's floor area or 750 sq ft, whichever is larger, or a whole basement or garden level — worth reading closely before sizing a unit.
Short-term rental of the ADU is not permitted, so the model here is long-term tenancy or family use.
And Center is one of only 30 Colorado jurisdictions certified ADU Supportive, which makes residents eligible for CHFA’s state-backed ADU financing — an interest-rate buydown and credit enhancement offered through participating lenders. Most of the Front Range doesn’t have this lever.
The federal benchmark for what an ADU rents for in Center.
Rents: HUD Fair Market Rents, huduser.gov.
Two ways to build the same unit in Center. Both figures are all-in — design, permits, foundation, utility connections and installation.
Published Front Range ranges for a comparable one-off build, 2025–26
≈ $2,100–$2,600 / month fully financed
Fits Center’s size rule
≈ $2,800–$3,500 / month fully financed
Fits Center’s size rule
Olerra ranges: published all-in project pricing, September 2026 — site preparation, foundation, utility connections and permitting included.
Free and specific to you. Want to go further?
Yes. The Center Code Of Ordinances permits accessory dwelling units (§44-73), subject to the size, height, setback and use rules quoted above from the ordinance text. Zoning district, lot size and setbacks still decide what fits on a specific lot — the free property check confirms yours.
Yes. An ADU is a new dwelling unit, so Center requires a building permit (plus any zoning or site-plan review the code calls for) before construction starts. Olerra's all-in price includes permitting, and factory-built units are inspected to the same building code as a site-built home.
Per the Center Code Of Ordinances: 750 sq ft for a detached ADU; an ADU built into a single-family house may be up to 30% of the house's floor area or 750 sq ft, whichever is larger, or a whole basement or garden level. Both Olerra Flex Flats — the 490 and the 735 — fit under this rule. The free property check confirms what fits on your lot.
No — rentals on a property with an ADU must be at least 90 days by written lease (Sec. 44-73(d)). Plan on long-term tenancy or family use.
Per the ordinance: No — no owner-occupancy requirement (the ADU and the main house must stay in undivided ownership).
A one-off site build with a general contractor typically runs about $500,000–$650,000 for a ~490 sq ft unit. Olerra's factory-built Flex Flats run $300,000–$365,000 (490) and $420,000–$465,000 (735) all-in — site preparation, foundation, utility connections and permitting included.
Same method, each city’s own ordinance. The Colorado hub lists every city, and the statewide ADU calculator covers any Colorado address.
Guides and real Colorado numbers from our team — a fresh pick every couple of weeks, or search for exactly what you need.
How to hire an ADU contractor in Colorado, the questions to ask, the red flags to avoid, how licensing works here, and modular versus site-built compared.
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Planning departments and journalists are welcome to reference this data.
Olerra ADU Cost Calculator — Center, CO. Rules last verified October 22, 2026 against the codified ordinance; page released October 22, 2026. https://www.olerra.com/adu-calculator/center/ <a href="https://www.olerra.com/adu-calculator/center/">Center ADU rules & costs</a> Page released October 22, 2026 · rules last verified October 22, 2026 · the oldest dated figure on the page is from October 22, 2026.
Planning estimates, not quotes or legal advice. Rules, fees, levies and rents change — confirm with the city and your lender before committing. Rules data: codified ordinance as of October 22, 2026, re-verified October 2026. Olerra pricing: published all-in project ranges, September 2026. Corrections: sales@olerra.com.
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