The City of Darien requires a building permit before you can build, modify, or replace a deck. The Community Development Department handles the entire process — from application to inspections — and the City has a dedicated Deck Information sheet that outlines what’s needed. Darien also has specific lot coverage rules that are worth understanding before you design, since they can directly affect how large your deck can be.
The Community Development Department
| Detail | Information |
| Department | Community Development |
| Address | 1702 Plainfield Rd, Darien, IL 60561 |
| Main Phone | (630) 852-5000 |
| Building Permits | (630) 353-8115 |
| CD Director | Dan Gombac — (630) 353-8106 / dgombac@darienil.gov |
| City Planner | Ryan Murphy — (630) 353-8113 / rmurphy@darienil.gov |
| Hours | Monday–Friday, 8:30 AM – 5:00 PM |
| Building Code | 2021 IRC / 2021 IBC |
| Forms & Permits | darien.il.us/reference-desk/forms-and-permits |
When a Permit Is Required
Per Darien’s municipal code, no building, electrical, mechanical, plumbing, or sewer system shall be constructed, enlarged, altered, repaired, moved, demolished, or changed unless a permit has been obtained. This applies to all new decks, structural modifications to existing decks, and any deck that includes electrical work or other mechanical connections.
Patios also require permits. The patio permit fee is a flat $50, and the City requires a pre-pour inspection for concrete patios and a final zoning inspection for paver patios.
What to Submit for a Deck Permit
You’ll need to provide:
- A completed Building Permit application
- A plat of survey showing deck/patio location, dimensions, and distance from lot lines
- A drawing or sketch of the proposed work, including dimensions
- Construction plans showing framing layout, footing locations, ledger board details, railing design, and stair dimensions
- Material specifications
- Contractor license information (all contractors must be licensed with the City)
Lot Coverage Rules — Why This Matters in Darien
Darien has two lot coverage limits that can directly affect your deck design:
| Coverage Rule | Limit | What It Includes |
| Total lot coverage | 50% of lot area | All structures, walks, driveways, patios, decks, pools, sheds, etc. |
| Rear yard coverage | 30% of rear yard | All structures, pools, patios, decks, walks, etc. in rear yard |
The rear yard limit catches most homeowners off guard. If you already have a patio, shed, or pool in your backyard, a new deck may push you over the 30% threshold even if total lot coverage is under 50%. Contact City Planner Ryan Murphy at (630) 353-8113 to confirm your available coverage.
Setback Requirements
Setbacks vary by zoning district. For accessory structures, the standard setback is 5 feet from side and rear lot lines. Corner lots require 15 feet from the corner side lot line. No structures are permitted within easements. For the principal structure and attached decks, setbacks are determined by your zoning district — R-1 has a 40-foot rear setback. Contact Community Development at (630) 852-5000 to confirm setbacks for your specific lot.
Contractor Licensing
All contractors and subcontractors must hold a current City of Darien contractor’s license. The license runs May 1 through April 30. Annual fee is $60, reduced to $30 after November 1. State-licensed plumbers, roofers, and fire alarm contractors are exempt from the fee per Illinois state code.
Code Requirements
Key requirements for residential decks in DuPage County:
- Footing depth of at least 42 inches (DuPage County frost line)
- Guardrails required for any deck surface more than 30 inches above grade
- Minimum guardrail height of 36 inches; baluster spacing no greater than 4 inches
- Ledger boards attached with approved fasteners; joist hangers at all connections
- Stair tread depth at least 10 inches, riser height no more than 7.75 inches
Inspections and Fees
After your permit is issued, the City requires inspections at footing, framing, and final stages. Inspections canceled without notice or failed inspections incur a re-inspection fee of $80 for the first occurrence and $100 for each subsequent re-inspection. Re-inspection fees must be paid before the next inspection is scheduled.
If any portion of your property is in a flood plain or wetlands, the permit process takes considerably longer due to additional regulatory compliance. Check with Community Development early if you’re unsure about your property’s flood zone status.
Choosing Materials
Our review of heat-resistant composite decking covers how different products handle DuPage County’s climate. For a contractor’s perspective on material trade-offs, see our breakdown of choosing the right decking material. And for help choosing colors, see our guide to selecting deck colors.
Ready to Start?
Platinum Decking designs and builds custom decks for homeowners in Darien and across the western suburbs. We handle the full permit process — from plan preparation through City submission and all required inspections. Call us at (224) 634-4345 to discuss your project.