ADU · St. Louis
ADU Construction in St. Louis, MO
The highest long-term ROI of any addition.
Brick construction traditions, pre-1940 housing stock, and the unusual political split between the independent city and St. Louis County make this a renovation market that rewards firms with deep local knowledge.
ADUs are the fastest-growing residential category in 2026 for a reason: they pay for themselves. We match you with firms that build to code and to rent, detached, attached, or garage conversion, with the local ordinance know-how that makes or breaks the project.
St. Louis market
ADU in St. Louis: what the market looks like
The Hill, Maplewood, Webster Groves, and Kirkwood carry active renovation demand in some of Missouri's oldest and densest urban housing. St. Louis brick construction, narrow lots, party walls, deep cellars, requires renovation techniques distinct from wood-frame markets. Clayton and Ladue represent the luxury tier. Lead paint abatement is a common and legally required part of pre-1978 renovation scopes. The St. Louis market is divided between the independent City and St. Louis County, two separate permit jurisdictions covering the same metropolitan fabric.
Permits in St. Louis
City of St. Louis Building Division and St. Louis County Planning are separate permit authorities with different staff, fee structures, and inspection requirements. Lead paint disclosure and RRP Rule compliance are enforced on all pre-1978 projects. The firms we match track which jurisdiction applies to each address and carry Missouri contractor licensing.
St. Louis conditions
Building adu for St. Louis conditions
St. Louis's lot rules, setbacks, and parking requirements decide what's buildable before any design starts, so the firms we match confirm zoning feasibility on your specific parcel first.
Our standard
What we require from adu construction firms in St. Louis
- Detached, attached, and garage-conversion ADUs
- Built to rent: separate metering and entrances
- Local ADU ordinance and setback expertise
- Income-property finish, built to rent well for years
ADU Construction in St. Louis, MO: your questions
What does adu construction cost in St. Louis, MO?
The Hill, Maplewood, Webster Groves, and Kirkwood carry active renovation demand in some of Missouri's oldest and densest urban housing. For adu construction specifically: Detached 400–800 sq ft: $100k–$250k. Garage conversions: $50k–$120k. Avg build ~$180k. National range: $50,000–$250,000. In St. Louis, MO, costs land near the national average for mid markets. Use our cost estimator for a scope-adjusted figure.
How long does adu construction take in St. Louis, MO?
A typical adu construction project runs 4 to 8 months. In St. Louis, the permit timeline matters as much as the build window: City of St. The firms we match commit the completion date in writing.
What permits does adu construction require in St. Louis, MO?
City of St. Louis Building Division and St. Louis County Planning are separate permit authorities with different staff, fee structures, and inspection requirements. Lead paint disclosure and RRP Rule compliance are enforced on all pre-1978 projects. The firms we match track which jurisdiction applies to each address and carry Missouri contractor licensing.
How do you match adu construction contractors in St. Louis, MO?
We vet remodeling firms in St. Louis before the first introduction: license verified, insurance confirmed, references called, complaint history reviewed. You describe the project, we send a short matched list of firms that work in St. Louis and specialize in adu construction. Free for homeowners.
Get matched for adu construction in St. Louis.
Tell us about your project. We hand you a short list of vetted local remodelers, free, and stay out of the rest. No phone-blasting, no pressure.