Last updated: September 24, 2026
What affects the price
Building an ADU is a major project, and the final bill depends on a few key things. Site prep is a big factor; if your land is sloped or needs extensive utility connections, costs go up. The materials you choose—from siding to kitchen finishes—also change the math significantly. Whether you’re building a detached unit or converting an existing garage shifts the permit requirements and structural work needed. We provide exact pricing confirmed free on the call.
About this service
Finding local builders means looking for teams that specialize in compact, efficient residential construction within your region. These professionals know the specific building codes for your city and can help you navigate site constraints like lot setbacks and utility lines. You need a local partner when you are ready to break ground and want a team that understands how to manage logistics and inspections in your immediate area to keep your project moving forward smoothly.
Frequently asked in St. Louis
What are the disadvantages of ADUs in St. Louis?
How much does an ADU cost in Missouri?
What are the rules for ADUs in St. Louis?
St. Louis has specific zoning ordinances that dictate ADU size, placement, and permitting. These rules can differ slightly by neighborhood, so consulting with local experts is vital. They can explain what's permissible on your property.
Is an ADU allowed in St. Louis, Missouri?
What is the process for building an ADU in St. Louis?
The process generally involves architectural design, obtaining permits from the City of St. Louis, and then construction. Local professionals understand the city's approval process well. They can ensure your project is compliant.
What affects the cost of an ADU in St. Louis?
The main cost factors include the ADU's square footage, the quality of interior and exterior finishes, and site preparation. The condition of existing utilities and foundation needs in St. Louis will also impact the overall price. Get a personalized quote.
Also serving nearby: O Fallon · Springfield · Columbia · Champaign · Peoria
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, Central West End, Soulard, Benton Park — and every surrounding area.
Areas we serve
Browse by state, then city.
Alabama (4)
All of Alabama · Birmingham · Huntsville · Mobile · Montgomery
Alaska (1)
Arizona (9)
All of Arizona · Chandler · Gilbert · Glendale · Mesa · Peoria · Phoenix · Scottsdale · Tempe · Tucson
Arkansas (1)
California (29)
All of California · Anaheim · Bakersfield · Chula Vista · Elk Grove · Fontana · Fremont · Fresno · Garden Grove · Glendale · Huntington Beach · Lancaster · Los Angeles · Modesto · Moreno Valley · Oakland · Oceanside · Ontario · Oxnard · Palmdale · Rancho Cucamonga · Riverside · Sacramento · San Bernardino · San Diego · San Francisco · San Jose · Santa Clarita · Santa Rosa · Stockton
Colorado (4)
All of Colorado · Aurora · Colorado Springs · Denver · Fort Collins
District of Columbia (1)
Florida (10)
All of Florida · Cape Coral · Fort Lauderdale · Jacksonville · Miami · Orlando · Pembroke Pines · Port St. Lucie · St. Petersburg · Tallahassee · Tampa
Georgia (2)
Hawaii (1)
Idaho (1)
Illinois (2)
Indiana (2)
Iowa (1)
Kansas (2)
Kentucky (2)
All of Kentucky · Lexington-Fayette · Louisville/Jefferson County
Louisiana (3)
Massachusetts (2)
Michigan (2)
Minnesota (2)
Missouri (3)
Nebraska (2)
Nevada (4)
All of Nevada · Henderson · Las Vegas · North Las Vegas · Reno
New Jersey (2)
New Mexico (1)
New York (4)
All of New York · Buffalo · New York · Rochester · Yonkers
North Carolina (7)
All of North Carolina · Cary · Charlotte · Durham · Fayetteville · Greensboro · Raleigh · Winston-Salem
Ohio (4)
All of Ohio · Akron · Cleveland · Columbus · Toledo
Oklahoma (2)
Oregon (3)
All of Oregon · Eugene · Portland · Salem
Pennsylvania (2)
Rhode Island (1)
South Dakota (1)
Tennessee (6)
All of Tennessee · Chattanooga · Clarksville · Knoxville · Memphis · Murfreesboro · Nashville-Davidson metropolitan government (balance)
Texas (16)
All of Texas · Amarillo · Arlington · Austin · Brownsville · Dallas · El Paso · Fort Worth · Frisco · Garland · Grand Prairie · Irving · Laredo · Lubbock · McKinney · Plano · San Antonio
Utah (1)
Virginia (5)
All of Virginia · Chesapeake · Newport News · Norfolk · Richmond · Virginia Beach
Washington (4)
All of Washington · Seattle · Spokane · Tacoma · Vancouver
