Adu services — St. Louis, MO

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total budget. The biggest factor is whether you choose a prefabricated unit or a custom build on-site. Site preparation is also significant; if your land requires extensive grading, utility trenching, or foundation work, costs will climb. Your choice of finishes—like kitchen cabinetry, flooring, and siding materials—also shifts the bottom line. We help you navigate these variables to find a setup that fits your property. Exact pricing confirmed free on the call.

About this service

ADU services manage the technical and creative side of building a secondary unit on your lot. Whether you are converting a garage or building a new structure from the ground up, you need these services to bridge the gap between architectural plans and physical construction. They help manage site preparation, utility connections, and structural integrity, ensuring your project is ready for occupancy without you having to coordinate multiple subcontractors independently.

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: Central West End, Tower Grove South, The Hill, Soulard, CWE — and every surrounding area.