Do I need a permit in Glen Ellyn, IL?
Glen Ellyn sits in DuPage County and enforces the 2021 International Building Code with Illinois amendments. The City of Glen Ellyn Building Department handles all permit applications for residential work. The key thing to understand: Glen Ellyn takes code compliance seriously and reviews plans carefully. A submitted permit that's incomplete or doesn't match the current code edition will be rejected, not approved-with-notes. That means you need to get the details right before you walk in—or file online through the city's permit portal.
Glen Ellyn's 42-inch frost depth (measured from the frost line in the Chicago area) governs footing depth for decks, shed foundations, and fence posts. That's 6 inches deeper than the IRC minimum of 36 inches, so any exterior structure sitting on soil needs to account for it. The city is also in IECC climate zone 5A north, which affects insulation requirements for additions and renovations. Most homeowners in Glen Ellyn are either doing deck work, finishing basements, replacing HVAC systems, or adding electrical circuits — all common projects that either require permits or sit in a gray zone depending on scope.
Owner-builders are allowed for owner-occupied residential projects in Glen Ellyn, but you must pull the permit in your name and pass all required inspections yourself. Contractor licensing is required for anyone else doing the work. The city does not allow unlicensed third parties to work under a homeowner's permit.
This page walks you through the permit landscape in Glen Ellyn: what needs a permit, what doesn't, how to file, typical fees, and where to go when you're stuck.
What's specific to Glen Ellyn permits
Glen Ellyn uses the 2021 IBC with Illinois amendments, adopted in 2023. That means code sections cited in older permit books or online forums may not apply. The city's Building Department interprets the code conservatively—if the code could be read two ways, Glen Ellyn typically chooses the stricter reading. This matters for gray-zone projects like finished basements (ventilation, egress windows, sump pump discharge) and deck attachments (ledger flashing, frost protection). Call the Building Department before designing a borderline project.
The 42-inch frost depth is critical and often overlooked. Deck footings, shed foundations, and fence posts must all extend below 42 inches. That's not a suggestion—it's enforced at footing inspection. If your deck posts or fence posts are in soil (not on concrete piers sitting on soil), they must go to 42 inches. This is especially important if you're replacing an old deck or fence and the previous footings are shallower.
Glen Ellyn requires a site plan for most structural permits. The site plan must show property lines, the location of the proposed structure, distances from lot lines, and existing structures. For a deck, fence, or addition, a simple sketch showing measurements and setbacks is usually sufficient. The #1 reason permits get rejected or delayed is a missing or incomplete site plan. Have your property survey or a recent plat in hand before you file.
The city offers an online permit portal for filing and tracking applications. Check https://www.glenbyellyn.org for access to the portal and the current fee schedule. Over-the-counter submissions are also accepted at City Hall during business hours (Mon–Fri, 8 AM–5 PM; hours subject to change, so call ahead). Plan review typically takes 2–3 weeks for residential projects. Structural work (additions, major renovations) takes longer than smaller projects (fences, sheds).
Glen Ellyn is in a Lake Michigan water-quality watershed, which affects stormwater handling for larger projects. Decks and small sheds usually don't trigger stormwater review, but additions and impervious surface expansion sometimes do. If you're adding a driveway or significantly expanding roof area, ask the Building Department about stormwater requirements before you design.
Most common Glen Ellyn permit projects
These are the projects Glen Ellyn homeowners ask about most often. Each has a different permit path, fee structure, and timeline. Click any project name to read the full breakdown for Glen Ellyn.
Decks and elevated structures
Decks over 30 inches high require a permit. Glen Ellyn enforces the 42-inch frost depth strictly. Ledger flashing must meet 2021 IBC standards. Typical permit: $150–$400 depending on size.
Fences
Fences over 6 feet require a permit. Corner-lot sight triangles are enforced. Pool barriers (required to be 4 feet minimum) always need a permit. Typical permit: $75–$150.
Additions and room expansions
All room additions, whether interior or exterior, require a permit. Plan review includes foundation, electrical, HVAC, and insulation. Typical permit: $400–$1,500+ depending on square footage.
Basement finishing
Finished basement conversions require a permit if you're adding walls, changing ventilation, or creating habitable space. Egress windows are required for bedrooms. Typical permit: $200–$600.
Sheds and detached structures
Detached structures over 120 square feet or taller than 15 feet typically require a permit. Utility sheds under 120 square feet may be exempt—verify with the Building Department. Typical permit: $100–$300.
Electrical work and circuits
New circuits, panel upgrades, hardwired appliances, and EV charging installations require electrical permits and inspections. Licensed electrician required. Typical permit: $75–$250.
HVAC replacement and installation
Furnace, air-conditioner, and heat-pump replacements usually require permits. Ductwork changes or extensions require a permit. Licensed HVAC contractor required. Typical permit: $75–$200.
Glen Ellyn Building Department contact
City of Glen Ellyn Building Department
Glen Ellyn City Hall, Glen Ellyn, IL (confirm address with city website)
Search 'Glen Ellyn IL building permit phone' or visit glenbyellyn.org for current number
Monday–Friday, 8 AM–5 PM (verify locally; hours may vary seasonally)
Online permit portal →
Illinois context for Glen Ellyn permits
Illinois adopts the 2021 International Building Code with state amendments. Glen Ellyn applies the state code as adopted by the City of Glen Ellyn. This means IRC sections (like IRC R403 for footings, NEC Article 230 for electrical service entrance, or IRC R802 for roof structure) are law in Glen Ellyn, unless the city or state has adopted a stricter amendment.
Illinois requires any contractor working on residential construction to be licensed by the Illinois Department of Financial and Professional Regulation (IDFPR). A general contractor, electrician, plumber, HVAC technician, or roofer working on your project must carry an active Illinois license. The homeowner is responsible for verifying that contractors are licensed—the city will not pull a permit under a homeowner's name if a licensed contractor is doing the work. Owner-builders are allowed for owner-occupied residential work in Glen Ellyn, but the permit must be in the homeowner's name and all inspections are the homeowner's responsibility.
DuPage County is in climate zone 5A north, which affects insulation R-values and air-sealing requirements for new construction and major renovations. The 2021 IECC (Illinois Energy Code) requires R-20 attic insulation minimum, R-13 wall insulation, and R-10 basement insulation in climate zone 5A. Any addition or finished basement that includes new walls or a new roof must meet these minimums.
Common questions
Do I need a permit for a deck in Glen Ellyn?
Yes, if the deck is more than 30 inches above grade. Glen Ellyn requires a permit for any elevated deck with stairs leading to grade. The deck must have footings extending at least 42 inches below grade to account for frost depth. A deck ledger (where the deck attaches to the house) must also meet flashing and structural requirements under the 2021 IBC. Typical permit is $200–$400. Small ground-level platforms under 30 inches may be exempt—verify with the Building Department before building.
What's the frost depth for Glen Ellyn and why does it matter?
Glen Ellyn's frost depth is 42 inches, measured from the soil surface down. Any structure (deck, fence, shed) that sits on a footing in soil must have that footing extend below 42 inches to prevent frost heave, which is the upward movement of soil caused by freezing and thawing. Posts, pilings, or foundation footings that don't go deep enough will shift up and down with seasonal frost cycles, breaking connections and destabilizing the structure. This is enforced at footing inspection—the inspector will measure the depth before you cover it.
Do I need a permit to replace my furnace or air conditioner?
Usually yes. Furnace and air-conditioner replacements in Glen Ellyn require a permit if you're installing a new unit or connecting new ductwork. A simple swap of the same unit in place might be exempt—ask the Building Department first. You must hire a licensed Illinois HVAC contractor. The contractor typically pulls the permit. If you're adding or extending ductwork, a permit is definitely required. Expect a $75–$150 permit fee and plan review of 1–2 weeks.
Can I finish my basement myself without a permit?
No. Any finished basement conversion—adding walls, changing ventilation, creating new bedrooms or habitable rooms—requires a permit. If you're just installing drywall on existing studs and not changing the room's classification, you may not need a permit. If you're adding an egress window (required for any bedroom below grade), you definitely need a permit. Plan review for a basement finish usually takes 2–3 weeks. Typical permit is $250–$500. Call the Building Department to discuss scope before you start.
What size shed can I build without a permit in Glen Ellyn?
Detached structures under 120 square feet and under 15 feet tall may be exempt from permitting in some cases. However, setback requirements (distance from lot lines) still apply, and zoning restrictions may limit where you can place a shed. A shed larger than 120 square feet or taller than 15 feet requires a permit. Verify with the Building Department before you build, because zoning violations and unpermitted structures can trigger orders to remove or costly violations.
Do I need a site plan when I apply for a permit?
Yes, for most structural permits (decks, additions, sheds, fences). The site plan must show your property lines, the location of the proposed structure, distances from lot lines, and existing buildings or structures. A simple hand-drawn sketch with measurements is usually acceptable for small projects like fences or sheds. For additions or major work, a professional survey or plat is preferred. The #1 reason permits are rejected is an incomplete or missing site plan. Have your property survey or a recent plat available before you file.
How much does a permit cost in Glen Ellyn?
Permit fees vary by project type and scope. Fences typically run $75–$150. Decks $150–$400. Electrical permits $75–$250. HVAC permits $75–$200. Additions and major projects are typically 1.5–2% of the estimated project cost, with a minimum fee. The city publishes a fee schedule on its website or at City Hall. Filing fees do not include plan-review fees or reinspection fees (if work fails inspection).
How long does plan review take in Glen Ellyn?
Routine residential permits (fences, sheds, simple electrical work) usually clear plan review in 1–2 weeks. Structural permits (decks, additions, basements) typically take 2–4 weeks. Major additions may take longer if the Building Department has questions. You can often speed up review by submitting complete, accurate site plans and plans that clearly show how the work complies with code. Resubmittals after rejection can add 1–2 weeks.
Do I need to hire a licensed contractor, or can I do the work myself?
Owner-builders are allowed for owner-occupied residential projects in Glen Ellyn. You must pull the permit in your own name and pass all required inspections yourself. However, some work requires a licensed contractor by Illinois state law: electrical work (licensed electrician), plumbing work (licensed plumber), HVAC work (licensed HVAC technician). For structural work like decks or additions, if you're doing the work yourself, you can pull the permit as the owner-builder. If you hire someone else, that person must be a licensed contractor in Illinois.
What happens if I build without a permit in Glen Ellyn?
The city can issue a violation notice, order you to obtain a permit for the unpermitted work, or demand removal of the structure. You'll also face fines. Unpermitted work can complicate future property sales, as title insurance and inspectors will flag it. It's far cheaper and faster to get a permit upfront than to remediate an unpermitted project later. If you've already built without a permit, contact the Building Department immediately to discuss options.
Ready to pull your permit?
Start by calling the Glen Ellyn Building Department or visiting the online permit portal at glenbyellyn.org. Have your property survey or plat, a sketch showing the location of your project and setbacks, and a clear description of the work ready. If you're unsure whether your project needs a permit, ask the Building Department directly—a 5-minute phone call saves weeks of headaches. Most Glen Ellyn permits process faster when the application is complete and accurate on first submission.