Check this with the city: The Des Plaines deck handout (December 2024) cites the 2015 code, and the city adopted the 2021 codes in December 2025. Confirm the footing and guard rules with the city.
Is a permit required?
Des Plaines has a Residential Decks building permit, applied for online in the Customer Self Service Portal.
"Building permits are applied for online at www.desplainesil.gov/buildingpermits."
Source: desplainesil.gov
The city requires permits for certain construction projects.
"The City requires permits for certain construction projects, as well as other registration and licenses."
Source: desplainesil.gov
What to bring
A plat of survey or site plan to scale showing the deck, its distances to all property lines and the material underneath.
"Plat of Survey / Site Plan with the location and dimensions of the deck, drawn to scale."
Source: desplainesil.gov
Construction plans must show framing, connections, elevations, stairs, handrails, guardrails and footing sizes and layout.
"Construction Plans showing framing layouts, framing member sizes, framing wood species and grade, connection details, deck elevations, stair and handrail details, guardrail details, footing sizes, and footing layouts."
Source: desplainesil.gov
A foundation supports (pier) plan showing pier size and spacing is required.
"Foundation Supports Plan (piers) showing the size of piers and spacing."
Source: desplainesil.gov
How to apply
Contractors listed on the application must be registered with the city before the permit is issued.
"All contractors listed on the application must be registered with the city before the permit is issued."
Source: desplainesil.gov
Staff can be reached at 847-391-5380 for help applying online, and questions go to permits@desplainesil.gov.
"If you have any issues while applying online, staff can be reached at: 847-391-5380."
Source: desplainesil.gov
Footings and frost depth
Postholes must be 42 inches deep if the deck is attached to the house, or 12 inches if free standing.
"Postholes must be 42” deep if attached to the primary structure or 12 inches if free standing."
Source: desplainesil.gov
How close to the property line
A deck may extend no farther than 12.5 feet into the required rear yard.
"May encroach no farther than 12.5 feet into the required rear yard"
Source: codelibrary.amlegal.com
A deck may extend no farther than 3 feet into required side and corner side yards.
"May encroach no farther than 3 feet into required side and corner side yards"
Source: codelibrary.amlegal.com
A deck may extend no farther than 5 feet into the required front yard.
"May encroach no farther than 5 feet into the required front yard"
Source: codelibrary.amlegal.com
Inspections
To request an inspection of work under permit, call 847-391-5382 or email permits@desplainesil.gov.
"To request an inspection for work under permit or an inspection of a rental dwelling, seek review of compliance of sign and more, please call 847-391-5382"
Source: desplainesil.gov
Other rules
On December 15, 2025 the city council adopted the 2021 I-Codes, including the International Residential Code.
"On December 15, 2025, City Council approved the adoption of the 2021 I-Codes"
Source: desplainesil.gov
Before anyone digs
Illinois law requires a call to JULIE, the state's one-call system, before digging deck footings. Call 811 or (800) 892-0123, or file online, at least 3 days before work starts. The call is free, and the locate is good for 25 days. On a hired job, the company doing the digging makes the call. More on Illinois deck rules
We are not the City of Des Plaines. Rules change, and some neighborhoods and HOAs have their own. Confirm with the city before you build. Spotted something out of date? Tell us.
Deck builders that serve Des Plaines
- Wood decks
- Composite decks
- PVC decks
- Composite decks
- PVC decks
- Screened and three-season porches