DC Structures
Why ADUs Are Booming in Illinois
From the towering skyline of Chicago to the historic small towns of Central Illinois, the state offers a diverse and rapidly evolving environment for ADU development. With ongoing housing shortages, aging-in-place needs, and rising demand for flexible rental options, accessory dwelling units are becoming an increasingly popular strategy for Illinois homeowners seeking affordability, multigenerational living solutions, or supplemental income.
While Illinois does not yet have a statewide ADU mandate, several major municipalities have adopted progressive ordinances. Chicago, for example, legalized coach houses and interior accessory dwelling units (attics and basements) in designated pilot zones beginning in late 2020—a program the city continues to expand.
Other cities—including Evanston and Oak Park—have long embraced accessory dwelling units as part of their housing diversity goals, providing clear pathways for homeowners to build backyard cottages, garage apartments, or interior conversions. At DC Structures, we help Illinois homeowners create durable, beautifully crafted prefab ADU kits designed for four-season climates. Whether you’re building a backyard dwelling unit in Chicagoland or a guest suite in Champaign-Urbana, our plans offer a streamlined, cost-effective way to enhance your property and lifestyle.
Our ADU Kits
Our prefab ADU models combine practicality, flexibility, and architectural versatility, making them well-suited for Illinois’ varied landscapes. Engineered with sustainable materials and crafted using precision CNC machining, our plans provide fast assembly, energy efficiency, and long-lasting durability against the state’s Midwest climate.
Sitka
SitkaCrafted for backyard use, whether as a guest suite, artist studio, or creative workspace, our Sitka ADU Kit offers limitless flexibility within a compact framework.
Average Cost to Build an ADU in Illinois
ADU costs in Illinois depend on location, climate considerations, structural design, and builder rates. Nationally, accessory dwelling units typically range from $60,000 to $285,000, with detached new construction on the higher end.
In Illinois, detached accessory dwelling units generally fall within the $140,000 to $260,000 range—though homeowners in the Chicago metropolitan area may experience higher costs due to labor rates and more complex permitting requirements. At DC Structures, we advise that turnkey ADU costs typically range between three to five times the price of the design and materials package, depending on utilities, excavation, interior finishes for the kitchen, bedroom, and bathroom spaces, and regional contractor pricing. For an accurate estimate for your Illinois build, we recommend requesting a custom quote from our team.
Illinois ADUs
Permitting, Zoning & ADU Regulations in Illinois
Illinois does not have uniform statewide ADU legislation, meaning regulations are managed locally at the city or county level. That said, several municipalities have become ADU leaders within the Midwest, offering clear, well-defined pathways for approval and construction.
Common ADU regulations in Illinois include:
- Zoning – Accessory dwelling units are permitted in select municipalities such as Chicago (within ADU pilot zones), Evanston, and Oak Park, typically within single-family residential districts.
- Size Restrictions – Many cities cap accessory dwelling unit size around 1,000 sq. ft. or set limits based on a percentage of the primary dwelling.
- Type & Placement – Attached, detached, and garage conversion dwelling units are typically allowed where permitted by zoning, subject to local setback and height requirements.
- Owner-Occupancy – Many municipalities require owner-occupancy in either the main home or the accessory dwelling unit, though Chicago does not require this in all pilot zones.
ADU Incentives, Grants & Financing in Illinois
Illinois does not currently offer statewide ADU-specific grants or tax incentives. However, several municipalities encourage homeowners to build accessory dwelling units—often as part of broader housing affordability initiatives. Illinois homeowners may also qualify for energy rebates for heat pumps, insulation upgrades, and high-efficiency HVAC systems installed in accessory dwelling units like backyard guest houses, tiny homes, and garage apartments. As accessory dwelling units gain momentum regionally and nationally, more Illinois municipalities may introduce grant or loan programs to support ADU architecture. Our team can also connect you with Illinois lenders experienced in ADU financing.
Best Cities & Counties to Build an ADU in Illinois
Illinois provides strong opportunities for ADU development in both urban and suburban markets. The following locations offer especially promising environments:
Chicago
The city’s ADU Ordinance allows basement conversions and coach houses in designated pilot areas.
Evanston
A notable and progressive adopter of accessory dwelling units, Evanston allows detached units and actively promotes housing diversity.
Urbana & Champaign
Strong rental demand fueled by major university student populations makes this area ideal for backyard cottages or studio-style tiny homes.
From revitalized urban cores to scenic small towns, Illinois offers a wide range of ideal settings for accessory dwelling unit development.
DC Structures
ADU Project Gallery
How ADUs Can Boost Property Value in Illinois
With the average Illinois home price around $280,000, accessory dwelling units offer a meaningful opportunity to expand usable living space and increase long-term equity. Since accessory dwelling units can increase property value by up to 30%, many Illinois homeowners may see an equity boost of $80,000 or more after adding a backyard living unit.
Rental income potential is equally strong. With statewide average rents around $1,950, and even higher prices in cities like Evanston or Chicago, homeowners could generate more than $115,000 in additional income over five years, depending on rental strategy and location. Whether used for long-term tenants, short-term visitors, family housing, or multigenerational living, sustainable backyard structures like accessory dwelling units offer Illinois homeowners a highly cost-effective way to maximize property value.
Start Your Illinois ADU Journey
Ready to explore back house possibilities for your Illinois property? Whether you’re located in Chicago, a college town like Urbana-Champaign, or a peaceful rural community, DC Structures is here to bring your accessory dwelling unit project to life.
We provide prefabricated guest house models, customizable floor plans, nationwide delivery, and expert support to guide you through permitting, financing, and construction with confidence.