ADU Construction in Denver, CO
Denver homeowners are adding ADUs for two reasons: rental income and family. Sometimes both. Arch Design & Build designs and builds permitted accessory dwelling units — architecture, structural engineering, and construction handled by one team
How Much Does an ADU Cost in Denver?
ADU construction in Denver starts at $120,000. Where your project lands depends on the type of ADU, the existing site conditions, and how much design and engineering work is required.
A garage conversion is typically the most cost-effective path. New detached construction costs more but gives you the most flexibility in size and layout. Basement conversions depend heavily on existing plumbing rough-ins and ceiling height.
The site assessment is what determines your number. We come out, review the lot, evaluate the existing structure, and tell you exactly what you’re working with. Free of charge
Garage conversion
Garage conversion to livable ADU
from
$75,000
Detached ADU
Detached ADU — new construction
from
$120,000
Basement conversion
Basement conversion to separate unit
from
$40,000+
How We Work
1
Free In-Home Consultation
We assess your lot, existing structures, and zoning classification. Denver has specific ADU eligibility rules — we’ll tell you upfront what’s possible
2
VR/3D Design
Full architectural design with VR walkthrough before permitting begins. You see the finished unit, not a floor plan on paper
3
Permitting
Denver’s ADU permit process runs through CPD and involves zoning review, building permits, and utility connections. We manage every step
4
Construction
Fixed price, one contact, permitted and inspected through certificate of occupancy
Financing Available
Don’t let budget hold you back. We work with trusted partners
ADU Permits in Denver
Do I need a permit to build an ADU in Denver?
Yes — without exception. Denver requires a full building permit, zoning compliance review, and separate utility connections for any ADU. The city has expanded ADU eligibility in recent years, but the permitting process remains detailed. Applications, structural engineering documentation, and inspections all pass through Denver Community Planning and Development.
We’ve done this before. We manage the entire process
Why Build an ADU Now?
Denver’s rental market is tight. A permitted, well-built ADU on a South Denver lot generates meaningful monthly income — enough to offset a significant portion of a mortgage payment. It also adds appraised value to the property as a separate rentable unit.
For homeowners with aging parents or adult children, an ADU provides independence without distance. Same lot, separate entrance, no shared walls
Why Arch Design & Build
VR design preview before a permit is filed
Full architectural and structural engineering in-house
Denver ADU zoning and permitting handled completely by our team
Fixed-price contracts — the number we give you is the number you pay
Licensed, bonded, and insured in Colorado
Where We Work in Denver
We build ADUs across South Denver and the surrounding neighborhoods — Washington Park, Hilltop, University Park, Mayfair, and Congress Park. Most of our Denver ADU work falls in zip codes 80209, 80210, and 80220
Frequently Asked Questions
Is my Denver property eligible for an ADU?
Most single-family lots in Denver are now eligible under the city’s updated zoning rules — but lot size, existing structures, and zoning classification all factor in. We’ll confirm eligibility during the free consultation.
Can an ADU be rented out immediately after construction?
Once the certificate of occupancy is issued, yes. Denver has specific short-term rental regulations — if Airbnb is part of the plan, we’ll walk you through what’s required before design begins.
How long does ADU construction take in Denver?
Design and permitting typically runs 2–4 months. Construction, depending on ADU type, runs another 3–5 months. Plan for 6–9 months total from first consultation to move-in.
Can you convert my existing garage into an ADU?
Yes — and it’s often the fastest, most cost-effective path. We’ll assess the structure, confirm zoning eligibility, and design the conversion to maximize livable space within the existing footprint.
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Ready to Add a Unit?
Free site assessment. Exact quote. Let’s see what your property can do
Arch Design & Build
9800 Mount Pyramid Ct, Suite 400, Englewood, CO 80112