Accessory dwelling unit builders near me — St. Louis, MO

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.

About this service

Local builders are teams that specialize in residential structures within your specific region. They understand the particular building codes and environmental requirements of your city, which helps prevent delays during inspections. You need a local builder when you are ready to break ground and want a partner who knows the local permit office and site conditions well. This ensures your project stays on track and follows all area-specific rules.

Frequently asked in St. Louis

Also serving nearby: O Fallon · Springfield · Columbia · Champaign · Peoria

All cities in Missouri →

More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of St. Louis — population 281,754; about 4,565 residents per square mile across 61.7 sq mi.

Neighborhoods served in St. Louis: The Hill, Tower Grove, Soulard, Central West End, CWE — and every surrounding area.