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
The cost of building an ADU depends on your choice of materials, the square footage, and whether you are doing a garage conversion or a new detached build. Site access and utility upgrades also play a big role in the final bill. Exact pricing confirmed free on the call.
Frequently asked in St. Louis
What are the disadvantages of ADUs in Missouri?
Disadvantages of ADUs in Missouri might include the initial investment in construction and ensuring compliance with local St. Louis zoning laws. You'll also need to consider the impact on your existing property's usability. Discussing these points with local professionals is wise.
How much does an ADU cost in Missouri?
The cost of an ADU in Missouri varies significantly based on its size, complexity, and the finishing materials used. Site preparation, foundation, and utility connections are also major cost factors. For an accurate estimate in St. Louis, a personalized quote is necessary.
What are the rules for ADUs in Missouri?
Missouri has general guidelines, but cities like St. Louis have specific zoning ordinances and building codes that govern ADUs. These often detail requirements for lot size, setbacks, and maximum dwelling unit size. Understanding these local regulations is crucial.
Is an ADU allowed in my St. Louis neighborhood?
ADUs are permitted in many residential areas of St. Louis, but specific zoning districts and historic preservation guidelines can influence feasibility. It's important to verify the rules for your particular street. We can help you get that information.
What are the rules for ADU construction in St. Louis?
St. Louis has specific building permits and zoning regulations for accessory dwelling units. These typically address density limits, parking requirements, and how the ADU integrates with the primary dwelling. The specialists we work with are knowledgeable about these local mandates.
Are there grants for ADUs in St. Louis?
Grant programs for ADUs in St. Louis are not commonly available and can vary greatly by specific city initiatives. While we cannot guarantee grants, obtaining a detailed quote will provide a clear financial overview for your ADU project.
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, Central West End, Tower Grove South, 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 (7)
All of Arizona · Chandler · Gilbert · Glendale · Mesa · Phoenix · Scottsdale · Tucson
Arkansas (1)
California (29)
All of California · Anaheim · Bakersfield · Chula Vista · Elk Grove · Fontana · Fresno · Garden Grove · Glendale · Huntington Beach · Irvine · Lancaster · Long Beach · Los Angeles · Modesto · Moreno Valley · Oakland · Oceanside · Palmdale · Rancho Cucamonga · Riverside · Sacramento · San Bernardino · San Diego · San Francisco · San Jose · Santa Ana · 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 · Hialeah · Jacksonville · Miami · Orlando · Pembroke Pines · Port St. Lucie · St. Petersburg · Tampa
Georgia (1)
Hawaii (1)
Idaho (1)
Illinois (2)
Indiana (2)
Iowa (1)
Kansas (2)
Kentucky (1)
Louisiana (3)
Massachusetts (2)
Michigan (1)
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 · Cincinnati · Cleveland · Columbus · Toledo
Oklahoma (2)
Oregon (3)
All of Oregon · Eugene · Portland · Salem
Pennsylvania (1)
South Dakota (1)
Tennessee (5)
All of Tennessee · Chattanooga · Clarksville · Knoxville · Murfreesboro · Nashville-Davidson metropolitan government (balance)
Texas (16)
All of Texas · Amarillo · Arlington · Austin · Corpus Christi · Dallas · El Paso · Fort Worth · Frisco · Garland · Houston · 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
