Accessory Dwelling Unit (ADU) Construction in Denver, CO — Costs $73,590 to $429,275

Accessory Dwelling Unit (ADU) Construction Cost Calculator for Denver

Adjusted for Denver's labor rate ($38.49/hr) and material costs (index 117).

Local Cost Breakdown

Accessory Dwelling Unit (ADU) Construction vs. Home Value in Denver

Planning a Accessory Dwelling Unit (ADU) Construction in Denver

Building permits are typically required for a accessory dwelling unit (adu) construction in Denver. The average permit fee in this area is $2,288, though costs vary based on project scope. Permit fees in this market are above average — factor them into your total budget. Plan for 6-18 months from start to finish.

A accessory dwelling unit (adu) construction is a complex project best left to licensed professionals. In Denver, skilled contractors charge an average of $38.49/hr, and the specialized nature of this work means cutting corners on labor can lead to costly rework.

For the median Denver household earning $76,237/year, this project at $183,975 represents a significant investment. Consider financing options or phasing the work to spread costs over time.

Financing the project? Compare current rates with Denver mortgage and HELOC rates to estimate monthly payments. For tax implications, mortgage interest deduction may apply — see SALT deduction guide.

Methodology & Local Data Sources

How we estimate accessory dwelling unit (adu) construction costs in Denver: Our local cost figure of $183,975 for Denver, CO is calculated by adjusting the national mid-range baseline of $150,000 using two location-specific factors:

1. Labor adjustment — 50%% of the project cost is labor. We multiply this by Denver's wage index, derived from BLS Occupational Employment and Wage Statistics for construction workers (SOC 47-0000). Denver skilled-trade labor averages $38.49/hr, compared to the national construction worker median.
2. Materials adjustment — 50%% of cost is materials. Denver's material cost index is 117 (national baseline = 100), based on regional shipping, lumber, concrete, and metal prices tracked by the Bureau of Labor Statistics Producer Price Index for Construction Materials.
3. Permit fees add $2,288 on average in Denver. Permit costs vary by project scope, square footage (200 sqft typical), and inspection requirements set by the local building department.
4. Cost-per-square-foot for this project in Denver: approximately $920/sqft, useful for comparing bids from contractors.

Authoritative data sources (US gov):

• BLS — Construction and Extraction Occupations Wages — labor rate baseline for Colorado
• BLS Producer Price Index — Construction Materials — monthly materials cost tracking
• U.S. Census Bureau — Denver QuickFacts — household income, demographics, housing
• DOE Building Energy Codes Program — energy efficiency requirements affecting accessory dwelling unit (adu) construction permits
• International Code Council (ICC) — IBC, IRC, and IECC code references most Colorado jurisdictions adopt
• EPA RRP Rule — Renovation, Repair, and Painting compliance for pre-1978 homes

Disclaimer: Cost estimates are based on regional averages and modeling — actual quotes from licensed contractors in Denver may vary ±15% based on project complexity, contractor backlog, and material availability. Always obtain at least 3 written bids before committing.

Reviewed by Brazora Monk · Last updated 2026

Find a Licensed Contractor + Permits in Denver

For a accessory dwelling unit (adu) construction in Denver, Colorado, you'll need a state-licensed contractor and (in most cases) a building permit. Use these official lookup tools instead of trusting general directory sites:

Why this matters: Hiring an unlicensed contractor in Colorado can void your homeowner's insurance, leave you liable for worker injuries, and result in code-violation fines. Always verify license + insurance before signing contracts.