A homeowner guide 

(Split by DuPage County and Will County Jurisdiction)

Naperville is unique because it spans two counties — DuPage County and Will County. While the Village of Naperville is the primary authority for permits and inspections, certain code adoptions and structural rules align with county-level standards.

This guide breaks down the essentials so Naperville homeowners can feel confident before starting a roof replacement, siding project, deck, or remodel.


1. Who Regulates Building Codes in Naperville

Naperville homeowners must comply with three layers of authority:

A. Village of Naperville (Primary Authority)

Naperville adopts and enforces:


  • 2021 International Residential Code (IRC)

  • 2021 International Building Code (IBC)

  • 2020 National Electrical Code (NEC)

  • 2021 International Existing Building Code

  • 2021 International Property Maintenance Code

    (Village of Naperville, 2023a)


B. DuPage County (North + West Naperville)

DuPage County follows adopted ICC building, structural, and safety standards that influence framing and environmental rules (DuPage County Building & Zoning, 2023).


C. Will County (South + East Naperville)

Will County enforces ICC-based building, fire, mechanical, and structural codes (Will County Land Use Department, 2023).


2. When You Need a Permit in Naperville

The Village requires permits for:


  • Roof replacement

  • Siding replacement

  • Window or door size changes

  • Deck construction or reconstruction

  • Basement finishing

  • Structural modifications

  • Additions

  • Electrical, plumbing, or HVAC changes

    (Village of Naperville, 2023b)



Even though Naperville spans two counties, every permit is issued by the Village, not the counties.


3. Roofing Requirements in Naperville

Village-Wide Rules

  • A permit is required for reroofing (Village of Naperville, 2023b).

  • Roofing must follow 2021 IRC and IBC requirements (Village of Naperville, 2023a).

  • Structural alterations (framing, rafters, load) may require stamped plans.



County Influence

  • DuPage County: Applies strict structural framing and sheathing standards under adopted building code (DuPage County Building & Zoning, 2023).


  • Will County: Applies ICC-based structural requirements for roof framing, trusses, and load modifications (Will County Land Use Department, 2023).


State Licensing

All roofing contractors must hold an Illinois roofing license under the Roofing Industry Licensing Act (Illinois Compiled Statutes, 2024).


4. Siding + Exterior Wall Requirements

Village-Wide Rules

Homeowners must follow IBC Chapter 14, which requires:

  • A water-resistive barrier (WRB)

  • Proper flashing around windows and doors

  • Correct fasteners

  • Weather-protection installation standards

    (International Code Council, 2021 as summarized in Barricade Building Products, 2020)


Siding replacement requires a permit (Village of Naperville, 2023b).


County Notes

  • DuPage County: Known for stronger oversight on moisture protection.

  • Will County: Follows ICC moisture/protection and wind-resistance requirements (Will County Land Use Department, 2023).



5. Deck Requirements (Permit + Safety)

Village Requirements

A deck permit requires:


  • Scaled drawings

  • Plat of survey

  • Structural details

  • Inspection schedule

    (Village of Naperville, 2023b)


Footing Depth

Naperville uses Illinois frost-depth standards:

  • Footings must extend at least 42 inches below grade
  • (City of Wheaton, 2024)

General Illinois Deck Rules

These apply regardless of county:

  • Guardrails required if deck is 30+ inches above grade

  • Joist hangers at all connections

  • Proper ledger board fasteners

  • Stair rise/run consistency

    (Hard Decks, n.d.)


County Differences

  • DuPage County typically performs more detailed framing inspections.

  • Will County is strict on ICC compliance for load and connection points.


6. Basement Finishing Rules

Village-Wide Requirements

Permits are required for

  • Framing

  • Electrical

  • Plumbing

  • HVAC

  • Egress

    (Village of Naperville, 2023b)


Egress Windows

Both counties follow ICC egress requirements for basement bedrooms (DuPage County Building & Zoning, 2023; Will County Land Use Department, 2023).


7. Contractor Requirements in Naperville

  • All contractors must register with the Village and provide insurance (Village of Naperville, 2023b).

  • Roofing contractors must hold a state roofing license (Illinois Compiled Statutes, 2024).




Reference List

Barricade Building Products. (2020). House wrap code requirements: Understanding the IRC & IBC. https://barricadebp.com/news/house-wrap-code-requirements

City of Wheaton. (2024). 2024 International Residential Code amendments. https://www.wheaton.il.us/1203/2024-International-Residential-Code-Amen

DuPage County Building & Zoning. (2023). Building code (clean version). https://cms5.revize.com/revize/dupage/Document_Center/Department/Building%20and%20Zoning/Building%20and%20permit/Building%20Code/Building%20Code%20Clean%20Version%2011-14-2023.pdf

Hard Decks. (n.d.). Illinois deck building codes: What homeowners should know. https://www.harddecks.com/deck-building-codes/

Illinois Compiled Statutes. (2024). Roofing Industry Licensing Act. https://www.ilga.gov/legislation/ilcs/ilcs3.asp?ActID=1360

Village of Naperville. (2023a). Adopted building codes. https://naperville.il.us/globalassets/media/documents/building/2021-adopted-codes.pdf

Village of Naperville. (2023b). Residential building permit requirements. https://www.naperville.il.us/services/building-permits/residential-building-permits/

Will County Land Use Department. (2023). Building codes and construction requirements. https://www.willcountygreen.com/