ADU (Accessory Dwelling Unit) Cost in St. Louis, MO (2026)
A ADU remodel in St. Louis typically costs between $59,000 and $294,000, with most homeowners spending around $127,500. Here's the local breakdown and what drives it.
Where the money goes
Typical split of a $127,500 ADU remodel in St. Louis.
What affects your St. Louis price
FAQ
How much does a ADU remodel cost in St. Louis?
In St. Louis, Missouri, a ADU remodel typically runs $59,000 to $294,000 in 2026, with most projects near $127,500. Local labor and material costs put St. Louis at about 98% of the US average.
What's included in that price?
A detached or attached secondary unit — foundation to finishes, plus utilities and permits.
Why is St. Louis different from the national average?
Construction labor rates, permit fees, and material delivery costs vary by metro. St. Louis's cost index is 0.98× the US baseline, which we apply to national ADU ranges.
How do I get an exact number for my project?
Use the free Reno estimate tool — describe your project (or upload a photo) and get a line-item estimate tied to your ZIP code, then share it with vetted local contractors.
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ADU (Accessory Dwelling Unit) cost in other cities
Other remodels in St. Louis
Ranges are 2026 market estimates based on national ADU costs adjusted by St. Louis's local construction cost index. Your actual cost depends on scope, finishes, and contractor. Get a project-specific estimate above.