Can I Build Second Story Addition in Chicago, IL? (2026)
Find out if you can build a second story addition in Chicago, IL. Rules, permit requirements, costs, and next steps.
Adding a second story in Chicago, IL is possible in most zones, subject to height limits and structural permit requirements.
A second story addition is one of the most complex home improvement projects in Chicago, IL. It requires a full building permit, structural engineering review, and must comply with the height limits for your zoning district. Unlike a ground-floor addition, a second story changes the roofline and structural load path of your entire home, triggering stricter engineering requirements. In Chicago, zone height limits range from 30 feet in RS-1 zones — verify your zone before planning.
Second Story Addition Rules in Chicago
Second Story Addition Rules in Chicago: Building permit required: Yes — all second story additions require a permit. Permit thresholds: All structural additions. Example height limit (RS-1): 30 feet, max 2 stories. Structural engineering drawings required. Setbacks apply to the full structure height. Chicago DOB permit required with architectural plans. Rear additions common on Chicago two-flat and greystones. Chicago bungalows have unique attic-expansion patterns.
Costs & Fees
Second story addition permit fees in Chicago: Based on construction value — typically $1,500–$8,000. Note: structural engineering fees ($2,000–$10,000+) are separate from permit fees.
Timeline
Plan check: 4-8 weeks. Construction typically 3-6 months for a full second story.
Next Steps
Next steps for adding a second story in Chicago: 1. Hire a structural engineer to assess your existing foundation and framing capacity. 2. Confirm your zone height limit and verify the addition meets all setback requirements. 3. Submit full structural plans and permit application to the Chicago Department of Buildings. 4. Inspections required at foundation reinforcement, framing, shear panels, and final.
Chicago Department of Buildings
Phone: (312) 744-5000
Website: https://www.chicago.gov/city/en/depts/bldgs.html
Online Permits: https://www.chicago.gov/city/en/depts/bldgs/provdrs/permits.html
Frequently Asked Questions
Can I build an ADU in Chicago?
Yes. Chicago's ADU Ordinance, expanded citywide in July 2022, allows both attached ADUs (basement or attic conversions) and detached coach houses (rear-yard ADUs typically built over a garage). Owner-occupancy is required — you must live in either the primary unit or the ADU. No replacement parking is required. A building permit from the Chicago Department of Buildings is required.
What is a coach house in Chicago, and is it the same as an ADU?
Yes. In Chicago, a coach house is the traditional term for a detached ADU — typically a 1- or 2-story structure built over a rear garage, accessed from the alley. Chicago's ADU Ordinance specifically authorizes coach houses up to 1,000 sqft and 22 ft tall. They are built in the rear yard, behind the principal building. Chicago has a rich history of coach houses from the late 19th and early 20th centuries.
How do I find the zoning of my Chicago property?
Use the City of Chicago Zoning Map at webapps1.chicago.gov/zoneinfo/ — enter your address to find zone designation, applicable district standards, and special overlay zones. You can also check the Chicago Zoning Ordinance (Title 17) at codelibrary.amlegal.com.
Are short-term rentals allowed in Chicago?
Yes, with a license. The Chicago Shared Housing Ordinance (effective 2016) requires a Vacation Rental License or Shared Housing Host Registration ($125/year). Properties in buildings where the condo or co-op association has voted to ban short-term rentals are prohibited. Chicago collects a 4.5% Shared Housing Surcharge plus state hotel tax.
What are the setbacks for a standard Chicago bungalow lot?
In RS-3 (the most common single-family zone for Chicago bungalows), setbacks are: 15 ft front, 2 ft side (minimum — many have 2 ft on one side and 0 on the other with a shared driveway), and 30 ft rear. Chicago's standard lot is 25 ft wide by 125 ft deep. The rear yard is typically used for detached garages accessed from the alley.
Source: Chicago Department of Buildings — Building Regulations. Last verified April 3, 2026. View source