Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Yes. Any deck attached to your house requires a permit from the City of Glendale Heights Building Department, regardless of size. Illinois adopts the IRC directly, and Glendale Heights enforces the 42-inch frost-depth rule for footings (Chicago zone).
Glendale Heights Building Department requires a permit for every attached deck — no exceptions for small projects. Here's what sets Glendale Heights apart from many DuPage County neighbors: the city processes permits through its main municipal office (not a satellite permit center), and online portal tracking is available but plan review typically requires an in-person or mailed submission for structural projects. Glendale Heights is in Cook County climate zone 5A, which means a 42-inch footing depth requirement — deeper than Wheaton or Downers Grove (which sit in warmer zones and use 36 inches). The city adopts the current Illinois Building Code (which mirrors the IBC code cycle), and the Building Department's FAQ explicitly states that ledger-board flashing compliance with IRC R507.9 is the single most-rejected detail on homeowner submissions. Most plan reviews take 10-14 business days; if rejections occur (typically for footing depth or flashing), resubmission adds another 7-10 days. Permit fees run $200–$400 depending on valuation, based on the city's 1.5% of construction-cost fee structure.

What happens if you skip the permit (and you needed one)

Glendale Heights attached deck permits — the key details

Glendale Heights enforces the Illinois Building Code (IBC 2021 edition as of 2024), which adopts the IRC with no local amendments that reduce deck requirements. The critical rule is IRC R507, which governs all deck construction. For attached decks, IRC R507.9 explicitly requires flashing at the ledger board to prevent water intrusion into the rim joist — this single requirement causes more rejections than any other detail in plan review. The city's Building Department FAQ states plainly: 'Ledger flashing must be installed per manufacturer specification and sealed with caulk; common rejections occur when homeowners use tar paper or aluminum flashing alone without a water-resistant barrier and sealant.' The ledger must be bolted to the house band board (not the rim joist alone) at 16 inches on-center, and the bolts must penetrate a minimum of 1.5 inches into the rim. IRC R507.9.2 requires a lateral load device (such as a Simpson Strong-Tie H-clip) at each ledger bolt to resist wind and seismic forces. Glendale Heights' Building Department requires this detail shown on the submitted plan; if it's missing, the application is rejected before any structural review begins.

Footings are the second most-critical detail, and Glendale Heights' 42-inch frost depth (Chicago zone) is stricter than surrounding suburbs. IRC R403.1.4.1 and Glendale Heights local practice both require footings to extend below the frost line. A typical deck footing in Glendale Heights uses a 4x4 PT post set in a 12-inch diameter concrete pier 48 inches deep (6 inches below frost). Homeowners often submit plans showing 36-inch or 40-inch depth, which the Building Department rejects. If your yard has poor drainage or clay soil (glacial till or loess are common in Glendale Heights), the inspector may also require a gravel base or footing bell; expect to discuss this during the footing pre-pour inspection. Posts must be UC4B (above-ground) pressure-treated lumber minimum, and the beam-to-post connection must use a post base bracket (Simpson ABU or equivalent) bolted to the post and fastened to the beam with ½-inch bolts at 16 inches on-center. Glendale Heights inspectors verify footing depth with a probe during the pre-pour inspection — no guessing.

Guard rails and stairs trigger additional IRC sections. IRC R312 requires a 36-inch minimum guardrail (42 inches in some jurisdictions, but Glendale Heights uses 36 inches for residential decks). The guardrail must resist 200 pounds of concentrated force applied horizontally; homeowners often submit designs with 2x4 balusters spaced 4 inches apart, which the code requires. Balusters must not allow a 4-inch sphere to pass between them — a common failure is 6-inch spacing, which is too loose. Stairs must comply with IRC R311.7: minimum 10-inch tread depth, maximum 7.75-inch riser height, and a minimum 3-foot-6-inch landing at the bottom. The landing must be the full width of the stairway (typically 3 feet for a standard 3-foot-wide stair) and extend 3 feet out. Many homeowners submit stair plans showing a 2x10 landing or a small platform; these are rejected. Glendale Heights requires a full-sized landing shown in plan view with dimensions labeled.

Electrical and plumbing on decks are permitted but trigger additional review. If you plan to add outlets, lighting, or a hot tub, those require separate electrical permits under the National Electrical Code (NEC) and Illinois amendments. NEC 406.9 requires deck outlet circuits to be GFCI-protected; most inspectors will verify this during the final electrical inspection. Hot tubs require a separate mechanical permit and spa-specific inspection. A small water-feature or rain-barrel (non-functional plumbing) may not require a plumbing permit, but the Building Department should be consulted before design. Many homeowners assume that adding electrical 'later' avoids review — it doesn't; if the deck structure shows outlet locations or conduit routing, the plan review will catch it and require an electrical permit upfront.

The timeline for a Glendale Heights deck permit typically runs 10-14 days for initial plan review, then 1-2 weeks for construction (footing pre-pour, framing, final). If rejections occur, add 7-10 days per resubmission. The city's Building Department portal (accessible via the City of Glendale Heights website) allows online submission of plans and payment, but for structural projects like decks, staff still recommend a phone call (or in-person visit) to confirm the submission format before uploading. Most inspections are scheduled via the portal or by phone; final approval is issued after the final inspection passes. Permit fees are $200–$400 depending on the construction valuation (which the city calculates at roughly 1.5% of deck cost). A $6,000–$15,000 deck typically costs $200–$300 in permit fees; larger or more complex decks may reach $400. No separate plan-review fees are charged; the permit fee covers plan review and all three inspections (footing, framing, final).

Three Glendale Heights deck (attached to house) scenarios

Scenario A
16x12 pressure-treated deck, 4 feet high, no electrical, corner lot in north Glendale Heights (Cook County frost zone)
A 192-square-foot deck attached to the rear of a 1970s ranch in north Glendale Heights requires a full permit and plan review. At 4 feet above grade, the deck exceeds the 30-inch height threshold, triggering structural review. The footings must be dug to 42 inches (Cook County frost depth), which is typical for Glendale Heights; a standard 4x4 PT post set 48 inches deep in a 12-inch diameter pier is code-compliant. The ledger board is attached to the band joist with ½-inch bolts at 16 inches on-center, and IRC R507.9-compliant flashing (aluminum with sealant and a water-resistant barrier beneath) must be shown on the plan. Common rejection here: homeowners submit a plan showing the ledger bolted directly to the rim joist or using tar paper under the flashing; the Building Department rejects this and requires a resubmission with proper ledger detail. The guardrail is 36 inches (shown on plan with balusters 4 inches apart). A 3-step stair with a full landing (3x3 feet minimum) exits to the yard; the landing is shown 3 feet out from the deck. The plan also specifies PT lumber (UC4B), beam-to-post brackets (Simpson ABU bolted with ½-inch bolts), and nail/screw schedules per the IRC. Permit fee: $250. Plan review: 12 business days (typical). Inspections: footing pre-pour (1-2 days after call), framing (1 week into construction), final (1 week after framing). Total timeline: 4-5 weeks from permit issuance to final approval. Total deck cost: $8,000–$12,000 (materials + contractor labor).
PERMIT REQUIRED (over 30 inches high, attached) | 42-inch footing depth required | Ledger flashing IRC R507.9 required | Plan review 12 business days typical | Permit fee $250 | 3 inspections included | Total project $8,000–$12,000
Scenario B
20x20 composite deck with built-in hot tub, 3 feet high, southwest Glendale Heights near DuPage line (mixed frost zones)
A 400-square-foot composite deck with an integrated hot tub near the DuPage County line in southwest Glendale Heights requires a permit, plus separate mechanical and electrical permits. The size (400 sq ft) and height (3 feet, above the 30-inch threshold) both trigger structural review. The footing depth is a local question here: southwest Glendale Heights is near the border with warmer DuPage County zones, but the city code applies the 42-inch frost depth citywide; confirm with the Building Department if your lot is in an unincorporated area (which would use DuPage County rules, typically 36 inches). Assume 42 inches for Glendale Heights proper. The deck framing for a 20x20 spans a larger area, requiring more posts (typically 8-12 posts depending on beam sizing) and larger beams (2x10 or 2x12 treated); the plan must show all post locations, footing depths, and beam sizing with span tables. The hot tub adds mechanical complexity: the spa requires its own equipment pad (typically 4x4 feet, concrete slab or gravel base), a GFCI circuit, and a dedicated 240V electrical line. Separate mechanical and electrical permits are required ($150–$200 each). The hot tub also requires plumbing review for drain and fill connections. A common issue: homeowners assume the deck permit covers the hot tub; it doesn't — three separate permits (deck, electrical, mechanical) are filed, each with its own plan review and inspection schedule. The ledger flashing, footing detail, and guardrail requirements are the same as Scenario A. Additional detail: if the hot tub's drain discharges to the yard, the Building Department may require a gravel infiltration area or permitting through the Public Works Department for stormwater compliance; this adds 2-4 weeks if required. Permit fees: deck $300, electrical $150, mechanical $200 = $650 total. Timeline: 4-6 weeks (parallel review, but staggered inspections). Total project cost: $20,000–$30,000 (composite + hot tub + labor).
PERMIT REQUIRED (over 30 inches, over 200 sq ft, attached) | Hot tub requires SEPARATE mechanical + electrical permits | 42-inch footing depth | Composite does NOT exempt from code | Deck permit $300 + electrical $150 + mechanical $200 = $650 | 5-6 inspections across three permits | Stormwater infiltration may be required | Total project $20,000–$30,000
Scenario C
10x10 pressure-treated ground-level deck, 18 inches high, rear yard, freestanding (not attached)
A 100-square-foot freestanding deck 18 inches above grade (under 30 inches) does NOT require a permit in Glendale Heights under IRC R105.2 (work exempt from permit). However, this is the exception, not the rule — the moment you attach this deck to the house (ledger board connection), it becomes an attached deck and requires a permit. Many homeowners confuse 'ground-level freestanding' with 'no permit'; the distinction is critical. If the deck is truly freestanding (sitting on concrete piers or a gravel pad with no connection to the house structure), no permit is required. If there is ANY ledger board connection to the rim joist, band joist, or house structure, a permit is required. The freestanding deck does NOT need to meet IRC R507 (deck attachment rules) because it's not attached; however, it still must comply with IRC R403 (footings and foundations) to prevent settling or rot. A freestanding 10x10 at 18 inches typically uses 4x4 PT posts on concrete pads (no digging required; the pads sit on grade). No guardrail is required at 18 inches (the code requires guards above 30 inches). If stairs are added (unlikely for 18 inches, but possible as a ramped entry), they must still comply with stair rules. The cost is much lower than a permitted deck: $1,500–$3,000 for a DIY or contractor build. Inspection: none required. The catch: if you later decide to attach it to the house, you must remove the freestanding deck, pull a permit, rebuild as an attached deck, and pay the permit fee. Glendale Heights Building Department will NOT allow you to 'add a ledger later' without retroactive permitting.
NO PERMIT REQUIRED (freestanding, under 30 inches) | BUT: any ledger connection makes it attached = PERMIT REQUIRED | No IRC R507 applies (not attached) | No inspections required | Total cost $1,500–$3,000 | Footings still need frost protection (18 inches is marginal; confirm with inspector for freestanding longevity)

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Glendale Heights 42-inch frost depth: why it matters for your footing design

Glendale Heights sits in Cook County, which is classified as Climate Zone 5A by the Illinois Building Code. This zone has a 42-inch frost depth — the depth to which the ground freezes in a typical winter. Frost heave occurs when soil freezes, expands, and pushes posts and foundations upward; if your footing is above the frost line, this heaving will lift the deck and cause structural failure (cracks in the ledger, separation from the house, and guardrail collapse). IRC R403.1.4.1 requires footings to extend below the frost depth in the jurisdiction. Glendale Heights strictly enforces this: the Building Department's inspection checklist specifically calls for a probe test at each footing to verify 42-inch depth or greater.

Nearby suburbs vary: Downers Grove (DuPage County, warmer zone) uses 36 inches; Wheaton uses 36 inches; Schaumburg (Cook County, similar to Glendale Heights) also uses 42 inches. If you've researched a neighbor's deck permit in another town, their footing depth may be different — do not copy it. Glendale Heights footings must be 42 inches minimum to pass inspection. A footing at 40 inches will be rejected and require rework.

Soil composition in Glendale Heights varies (glacial till near the Des Plaines River, loess deposits to the west, clay to the south), but frost depth is uniform across the city. The 42-inch requirement applies regardless of soil type. During the footing pre-pour inspection, the inspector will probe down 42 inches or more to confirm depth; if groundwater or clay prevents digging to 42 inches (rare but possible in low-lying lots near the river), the inspector may require helical piers or a frost-protection system (foam board or insulation around the footing) — this adds cost and complexity. Confirm site conditions with the Building Department before finalizing the design.

Ledger board flashing: the number-one rejection reason in Glendale Heights plan review

The Glendale Heights Building Department's permit-review FAQ explicitly highlights ledger flashing as the most-rejected detail. IRC R507.9 requires flashing at the ledger-to-house connection, installed per the flashing manufacturer's specification, and sealed with compatible caulk. The typical code-compliant installation uses a Z-flashing or J-flashing (aluminum or stainless steel) over the top of the ledger board, with a water-resistant barrier (self-adhesive membrane or asphalt-saturated felt) underneath the ledger. The flashing extends at least 4 inches up the rim joist and down over the ledger. Caulk (polyurethane or silicone, not acrylic latex) seals all edges.

Common rejections in Glendale Heights submissions: (1) Tar paper under the flashing instead of a water-resistant barrier — the Building Department considers tar paper insufficient; (2) No flashing shown on the plan, only a note 'flashing per code' — the Department requires a detailed drawing or reference to the flashing manufacturer specification; (3) Flashing that only covers the ledger top, not extending up the rim joist — rejected; (4) Aluminum flashing without a water-resistant barrier underneath — the Department requires both. The remedy is resubmission with a corrected detail, typically showing a cross-section of the ledger-to-house connection with flashing, barrier, caulk, and bolts clearly labeled.

Cost impact: proper ledger flashing adds $200–$400 to deck construction (materials + labor). It's worth doing right the first time; rejections delay your permit approval by 7-10 days and may require contractor rework. The Building Department will verify flashing during the framing inspection; if it's non-compliant, the inspector will issue a 'correction notice' and schedule a re-inspection. Plan for this in your timeline if you have doubts about the flashing detail.

City of Glendale Heights Building Department
Glendale Heights Village Hall, 100 S. Main Street, Glendale Heights, IL 60139
Phone: (630) 260-2300 | https://www.glendaleheights.org (check for online permit portal or e-permit link)
Monday-Friday 8:00 AM - 5:00 PM (closed city holidays)

Common questions

Do I need a permit for a ground-level deck under 200 square feet?

Only if it's freestanding and under 30 inches high. If it's attached to the house (has a ledger board), you need a permit regardless of size. If it's freestanding and under 30 inches, no permit is required under IRC R105.2. The moment you add a ledger connection, the exemption is void and a permit becomes mandatory.

What is the frost depth requirement in Glendale Heights?

42 inches. Glendale Heights is in Cook County Climate Zone 5A, which requires footings to extend 42 inches below grade to prevent frost heave. This is deeper than some surrounding suburbs (Downers Grove uses 36 inches). The Building Department's inspector verifies footing depth with a probe during the pre-pour inspection.

How much does a deck permit cost in Glendale Heights?

Permit fees are $200–$400 depending on the deck's estimated construction cost. The city charges approximately 1.5% of the valuation. A $10,000 deck typically costs $200 in permit fees; a $20,000 deck costs around $300–$400. The fee covers plan review and three inspections (footing, framing, final). Additional permits for electrical or mechanical work cost extra ($150–$200 each).

What happens if my ledger flashing doesn't comply with the code?

The Building Department will reject your plan during initial review and require resubmission with a corrected detail. If the flashing is installed non-compliantly during construction, the framing inspector will issue a correction notice and schedule a re-inspection. Improper flashing leads to water intrusion and rim-joist rot, which creates costly damage. Get the detail right on the plan to avoid delays.

Can I build an attached deck as an owner-builder without a contractor?

Yes, Glendale Heights allows owner-builders to pull permits for owner-occupied residential projects, including decks. You do not need to be licensed. However, you are responsible for submitting plans that comply with IRC R507 and passing all three inspections. Many owner-builders hire a contractor for the actual construction or consult a structural designer to produce compliant plans. The permit fee is the same whether you build it yourself or hire someone.

How long does plan review take for a deck permit in Glendale Heights?

Initial plan review typically takes 10-14 business days. If rejections occur (usually for footing depth, ledger flashing, or stair dimensions), resubmission adds another 7-10 days. Once approved, construction inspections (footing pre-pour, framing, final) are scheduled via the permit portal or by phone. Total timeline from permit issuance to final approval is usually 4-6 weeks.

Do I need a separate electrical permit if I'm adding outlets or lighting to my deck?

Yes. Electrical work requires a separate electrical permit under the National Electrical Code (NEC) and Illinois amendments. If your deck plans include outlet boxes or conduit routing, the structural plan review will catch it and require you to file an electrical permit. Outlet circuits on decks must be GFCI-protected per NEC 406.9. Budget $150–$200 for the electrical permit and separate inspection.

What is the required guardrail height on a deck in Glendale Heights?

36 inches minimum, measured from the deck surface to the top of the guardrail. The guardrail must resist 200 pounds of horizontal force and have balusters spaced no more than 4 inches apart to prevent a sphere from passing through. Glendale Heights does not require the stricter 42-inch height that some other jurisdictions enforce.

If I skip the permit and the city finds out, what are the penalties?

Glendale Heights issues stop-work orders with $500–$2,000 fines and requires retroactive permitting with doubled permit fees. Insurance claims for deck damage or injury will be denied if unpermitted work is discovered. Illinois disclosure law requires you to reveal unpermitted work at resale, which can kill buyer interest and lower the sale price. Refinancing or HELOC lenders may freeze approval until the work is permitted or removed. The cost of penalties, remediation, and resale complications far exceeds the upfront permit fee.

Can I build a deck attached to my house without hiring an engineer for the plans?

You can submit plans you create yourself or have a contractor draft, but they must comply with IRC R507 and be detailed enough for the Building Department to review. Most homeowners use framing plans from online sources (which may not be site-specific) or hire a contractor who has standard details. If your submission is incomplete or non-compliant, the Department will reject it. For complex decks (very large, tall, or in unusual soil conditions), hiring a structural engineer ($300–$800) ensures compliance on the first submission and can save time and money.

Disclaimer: This guide is based on research conducted in May 2026 using publicly available sources. Always verify current deck (attached to house) permit requirements with the City of Glendale Heights Building Department before starting your project.

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