Research by DoINeedAPermit Research Team · Updated May 2026
The Short Answer
Round Lake Beach requires a building permit for any deck attached to your house. No exceptions. The application triggers structural review of ledger flashing, footing depth to the local 42-inch frost line, guardrail design, and stair geometry.
Round Lake Beach, like most northern Illinois municipalities, adopts the current Illinois Building Code (based on the IBC) and enforces it through the City Building Department. The critical city-specific detail: Round Lake Beach is in a 42-inch frost-depth zone (per USDA SSURGO and local construction history), which means every deck footing must go 42 inches deep — deeper than many homeowners expect and deeper than some southern Illinois towns require. The city also requires ledger-flashing plans that specifically comply with IRC R507.9 (the standard metal flashing with slope and drainage plane detail), and many initial submissions get flagged for inadequate ledger documentation. Round Lake Beach's permit office has moved to online filing and pre-screened plan submission in recent years, which speeds approval IF your plans are complete upfront — but it also means incomplete plans get a hard rejection rather than a back-and-forth chat. Expect $200–$400 in permit fees (1.5–2% of project valuation) and 2–3 weeks for plan review if drawings are clean.

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

Round Lake Beach attached deck permits — the key details

Round Lake Beach requires a building permit for any deck attached to a residential structure, regardless of size. This is stated in the City of Round Lake Beach Building Code, which adopts the Illinois Building Code and ICC standards. The attachment of a ledger board to the house triggers structural review, even if the deck is small or low. There is no exemption for attached decks under 200 square feet or under 30 inches above grade in Round Lake Beach — the attachment to the house is the permit trigger. Freestanding decks (not attached to the house) may be exempt if they are under 200 square feet AND under 30 inches above grade, but the moment you add a ledger, you need a permit. This rule is stricter than some nearby municipalities and reflects the city's emphasis on water intrusion prevention and ledger-connection safety. Plan accordingly: if you are considering a freestanding platform instead of an attached deck, that may avoid a permit, but you must document that it truly does not bear on the house structure.

The second major Round Lake Beach requirement is footing depth. The city enforces a 42-inch minimum frost depth for all footings (deck posts, porch footings, etc.). This is deeper than the 36-inch requirement in southern Illinois and reflects Round Lake Beach's location in the Chicago metro area's glacial-till soil zone. The reason: frost heave. When water in soil freezes, it expands; if a footing is above the frost line, winter freezing will lift the footing, causing the deck to rack, settle unevenly, and eventually fail. USDA SSURGO data and the Illinois Department of Natural Resources confirm the 42-inch frost depth for Lake County. Your deck plan MUST specify footings dug to 42 inches below finished grade, with a concrete pad below (minimum 4 inches) and the post set in the concrete. Many DIY plans show shallower footings; the city will reject those plans. In the inspection sequence, the Building Department will require a footing pre-pour inspection (or, in some cases, a photo inspection before concrete is poured) to verify depth. Hire a surveyor or mark the footing hole with a depth gauge and photograph it before calling for inspection.

Ledger flashing is the third critical detail and the source of many rejections in Round Lake Beach. IRC R507.9 requires a metal flashing or peel-and-stick membrane between the house rim band and the deck ledger board. The flashing must slope away from the house (minimum 1/8 inch per foot), extend at least 4 inches up the house sheathing, lap over exterior cladding, and have a continuous drain plane below. Many homeowners install a ledger with silicone caulk alone — that is not code-compliant and will be flagged. The Round Lake Beach Building Department's plan-review checklist explicitly includes a ledger-flashing detail callout. Your deck plan must include a cross-section drawing showing the ledger, the flashing, the house band, and drainage. If you are hiring a contractor, confirm that the proposal includes a proper flashing plan and that the ledger will be bolted to the house rim band (not the rim joist, not through the rim band — to the rim band) at 16 inches on center, per IRC R507.8. The ledger bolts must be galvanized or stainless steel; ordinary bolts will rust and fail within 10 years.

Guardrail and stair dimensions are the fourth detail. Any deck over 30 inches above grade requires a 36-inch-tall guardrail (measured from the deck surface to the top of the rail). The rail must resist a 200-pound horizontal force without deflecting more than 1 inch. Round Lake Beach does not require 42-inch rails (some jurisdictions do), but 36 inches is the minimum. Balusters (the vertical spindles) must not allow a 4-inch sphere to pass between them — this is the 'toddler gap' rule. Stairs must have treads at least 10 inches deep and risers no more than 7.75 inches tall; the landing at the deck must be the same width as the stair width, and the landing must be at least 36 inches deep. If your deck stairs lead to a sloped yard, you may need a mid-run landing if the vertical height is more than 3 feet; Round Lake Beach's inspectors will check this. These dimensions are in IRC R311.7 and are non-negotiable. Plan-review drawings must show stair dimensions, guardrail height, and baluster spacing with call-outs; a note saying 'per code' is not sufficient.

Finally, electrical and plumbing add complexity. If you plan to add outdoor outlets, lighting, or heating elements to the deck, you will need a separate electrical permit and NEC-compliant wiring (GFCI protection for all outdoor outlets, buried wire in PVC conduit if the wire crosses the yard, etc.). If you plan a deck with a hot tub, that is a plumbing permit. Round Lake Beach's permit office issues these as separate permits, but they are coordinated in the review process. A simple pressure-treated wood deck with no utilities does not trigger electrical review. Most attached-deck permits in Round Lake Beach are plan-reviewed in 2–3 weeks if drawings are complete; if you have utilities or are proposing non-standard materials (composite, vinyl, aluminum), add another week. The city does not offer over-the-counter (same-day) approvals for decks; all are submitted online (via the permit portal) and reviewed by staff. You will receive an email approval or a list of required corrections within 15 business days.

Three Round Lake Beach deck (attached to house) scenarios

Scenario A
12x16 attached pressure-treated deck, 4 feet above grade, in a standard suburban lot (no HOA, no historic overlay)
You are building a 12-by-16-foot (192 sq ft) deck on the back of your house in a typical Round Lake Beach subdivision. The deck will be 4 feet above the yard (48 inches), so it will require a 36-inch guardrail all around and a landing at the base of the stairs. You plan to use pressure-treated lumber, bolted ledger with metal flashing, and concrete footings. The permit process: submit a plan showing the ledger flashing detail (cross-section), the footing depth (42 inches to the frost line, with a 4-inch concrete pad below), guardrail height (36 inches from deck surface), and stair dimensions (10-inch treads, risers no more than 7.75 inches, 36-inch-wide landing). Round Lake Beach Building Department will review the plan in 2–3 weeks and either approve it or ask for corrections (most commonly, they will ask for more detail on the ledger flashing or a note confirming the 42-inch frost depth). Once approved, you will receive a permit number and a right to start work. You are required to call for a footing pre-pour inspection before you pour concrete; the inspector will come out and verify that the holes are 42 inches deep and located correctly. Then you frame the deck and call for a framing inspection (ledger connection, beam-to-post connections, joist spacing, guardrail blocking). Finally, a final inspection after the stairs, railing, and deck surface are complete. Total timeline: 2–3 weeks for plan review, then 4–8 weeks for construction and inspections (depending on your contractor's schedule). Permit fee: $200–$300 (typically 1.5% of the $12,000–$18,000 project valuation).
Permit required | 42-inch frost depth required | Metal flashing detail mandatory | Guardrail 36 inches min | Footing pre-pour inspection required | Permit fee $200–$300 | Plan review 2–3 weeks | Total project cost $12,000–$20,000 (labor + materials + permits)
Scenario B
8x12 freestanding deck, 18 inches above grade, rear corner of lot, no house attachment
You are planning a small platform deck in the corner of your yard, detached from the house. The deck is 96 square feet (under 200 sq ft), 18 inches above grade (under 30 inches), and has no ledger. This deck is exempt from the permit requirement under Illinois Building Code (IRC R105.2), which excludes certain freestanding structures. Round Lake Beach will not require a permit for this project. However, there are important caveats: (1) if the deck posts are within 6 feet of the property line or within a utility easement, the city may have site-plan or zoning questions — check the zoning code or call the city to confirm the location is allowed. (2) If the deck is on a slope or in a flood-prone area, you may need a surveyor or drainage engineer to confirm no fill is occurring in a wetland or floodplain. (3) If the deck will later be attached to the house (ledger added), you will then need a permit for the modification. (4) If the deck is more than 18 inches high and you live in a flood zone, check FEMA flood maps; elevated structures may trigger floodplain development rules. For a typical rear-corner freestanding deck on a dry lot with no zoning conflicts, no permit is needed. If you later want to upgrade the deck or add a roof, contact the city to see if the modification triggers a permit. Many homeowners build a small freestanding deck first, then later add a ledger to connect to the house — at that point, a permit is required for the modification.
No permit required (≤200 sq ft, ≤30 inches, freestanding) | Zoning check recommended | Flood-zone check recommended | Cost $2,000–$5,000 | No permit fees
Scenario C
20x20 attached composite-deck, 5 feet high, with electrical outlets and a built-in bench, on a corner lot in a historic district
You are proposing a larger, upgraded 20-by-20-foot composite-deck (400 sq ft) with built-in seating, two weatherproof electrical outlets, and 5 feet of height above grade. The house is in Round Lake Beach's historic district (if applicable; check with the city). This project triggers multiple permits. First, the deck itself requires a building permit for the structure, ledger, footings, guardrail, and stairs — same as Scenario A, but with larger dimensions. The plan must show all details to the same standard, including 42-inch footings, metal flashing, 36-inch guardrails, and correct stair geometry. Second, the electrical outlets require a separate electrical permit and NEC compliance: all outdoor outlets must be GFCI-protected, the wire must be buried in PVC conduit at least 6 inches deep (12 inches in Round Lake Beach if the line crosses a driveway), and a licensed electrician should pull the electrical permit. The city will issue both permits, but the electrical plan review may take an additional week. Third, if the deck is in a historic district, Round Lake Beach may require the Historic Preservation Commission to review the design. This is NOT a building permit; it is a separate design review. Composite materials, colors, and railings may be subject to approval. Contact the Historic Preservation Commission before you finalize the design. The combined timeline: 2–3 weeks for building-permit review, 1 week for electrical-permit review, 2–3 weeks for historic-design review (if required). Total permit fees: $300–$450 (building permit $250–$350 + electrical permit $50–$100). Many homeowners building larger decks with utilities hire a contractor who handles permits; if you are doing it yourself, factor in time to coordinate three separate departments.
Permit required (attached, >200 sq ft, >30 inches) | Electrical permit required (separate) | Historic-district review may apply | 42-inch footings required | Metal flashing detail mandatory | GFCI outlets required (NEC 210.8) | Permit fee $300–$450 | Plan review 3–4 weeks | Total project cost $20,000–$35,000

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Round Lake Beach's 42-inch frost depth: why it matters and how to verify it

Round Lake Beach is located in Lake County, Illinois, in USDA Plant Hardiness Zone 5a and a seismic zone with glacial-till soils. The frost depth (the depth below the surface where soil temperatures remain above 32°F year-round) is 42 inches, according to USDA SSURGO soil surveys and the Illinois Department of Natural Resources. This is deeper than the southern Illinois frost depth of 36 inches and reflects the colder winters and deeper frost penetration in the Chicago metropolitan area. When you dig a deck footing, every inch above the frost line increases the risk of frost heave — the upward movement of soil and footings due to ice formation in winter.

Frost heave is not a theoretical issue. If a deck footing is set 30 inches deep (12 inches above the frost line), water in the soil between 30 and 42 inches will freeze and expand during winter, lifting the footing by 1/4 to 1/2 inch per winter cycle. Over 5–10 years, the cumulative lift can be 3–5 inches, which will cause the deck to rack (twist), develop gaps between the rim joist and the house, and eventually fail. Cracked or separated ledgers are a sign of frost heave. Round Lake Beach's Building Department requires the 42-inch depth specifically to prevent this failure. The city's inspectors will not approve a footing plan that shows anything shallower.

To verify the frost depth on your property, you have several options. (1) Hire a surveyor ($200–$500) to mark the frost line on your site and photograph it. This is the most formal and is sometimes required if there are disputes. (2) Contact the USDA Natural Resources Conservation Service (NRCS) office in Round Lake Beach and request the SSURGO soil map for your property; it will specify the frost depth for your soil type. (3) Call the Round Lake Beach Building Department and ask what frost depth they enforce for your address — they will tell you 42 inches for the city. (4) When you submit the permit plan, explicitly note on the footing detail that footings will be dug to 42 inches below finished grade, with a 4-inch concrete pad below. The inspector will verify on-site during the footing pre-pour inspection. If your yard has a slope, measure the frost depth from the lowest grade point on the property; if the site is sloped, the footing on the downhill side may need to be even deeper.

If you are building a deck in late fall or winter, excavating 42 inches may be challenging due to frozen ground. Plan to dig footings in spring or early summer. If you must build in winter, use a snow-removal company with an excavator or rent one yourself; a standard shovel will not cut 42 inches through frozen soil. If you hit bedrock or a water table before 42 inches, call the city; there are alternate footing designs (pier blocks, helical anchors) that the inspector may approve, but this must be documented in the plan review, not discovered on-site.

Ledger flashing and water intrusion: why IRC R507.9 is non-negotiable in Round Lake Beach

Water intrusion at the deck-to-house connection is the most common cause of wood rot, mold, and structural failure in decks. The ledger board is bolted to the house rim band, and if water is allowed to flow behind the ledger and into the rim board, the rim board will rot within 3–5 years. This is not a cosmetic issue; rotted rim boards compromise the structural integrity of the house and can lead to foundation movement. Round Lake Beach's Building Department requires IRC R507.9-compliant flashing specifically to prevent this failure. The rule is not optional.

IRC R507.9 requires a metal flashing (typically L-shaped aluminum or galvanized steel) or a peel-and-stick membrane between the house rim band and the deck ledger. The flashing must (1) slope away from the house at a minimum 1/8 inch per foot slope (so water runs off, not toward the house), (2) extend at least 4 inches up the house sheathing (or longer if the house has siding — the flashing must lap over the siding so water sheds down and away), (3) be continuous (no gaps), and (4) have a drainage gap below the ledger so water that does get behind the flashing drains out rather than pooling against the rim board. In practice, most carpenters install 1x spacers between the ledger and the rim board to create a 1-inch air gap, then install the flashing above the rim band, sloping and sealed at the edges.

When you submit your deck plan to Round Lake Beach, include a detail drawing (at least 1/2 inch = 1 foot scale or larger) showing the ledger, the house rim band, the flashing, the siding, the drainage gap, and the bolts. The drawing should be labeled with material callouts: 'aluminum L-flashing, 1/8 inch per foot slope,' '5/8-inch galvanized bolts, 16 inches on center,' '1-inch air gap, 1x6 spacer,' 'house rim band,' 'exterior siding' (specify: vinyl, fiber cement, wood, brick), 'flashing extends 4 inches up house sheathing.' Many first-time submittals to Round Lake Beach lack this detail or show a ledger bolted directly to the rim board with caulk around it — the city will reject and ask for a revised detail. Build this time into your planning.

After the deck is built, inspect the flashing annually (at least once per fall) to confirm it is still sloped, not crushed or bent, and not leaking. If you see water staining on the house band below the deck, the flashing may be failed and the rim board may be rotting. Call a contractor immediately. Replacing a failed ledger and rim board is a $2,000–$5,000 repair and can take weeks. Proper flashing installation during the initial build takes one extra hour and costs $50–$100 in materials; it is insurance against a much larger failure.

City of Round Lake Beach Building Department
Contact Round Lake Beach City Hall, Round Lake Beach, IL 60073
Phone: (847) 546-2400 (verify current number with the city) | https://www.roundlakebeachil.com/permits (verify current portal URL)
Monday–Friday, 8:00 AM–5:00 PM (verify with the city)

Common questions

Can I build a deck without a permit if I do the work myself?

No. Round Lake Beach requires a permit for any attached deck, regardless of whether a contractor or the homeowner does the work. The permit is tied to the property and the structure, not the builder. Owner-builders are allowed in Illinois, but you must still obtain a permit, pay the fee, and pass inspections. Skipping the permit is illegal and will result in fines, insurance denial, and a title cloud when you sell.

What is the difference between a permitted and unpermitted deck if the work is done correctly?

If the work is done correctly, the structure will be sound, but an unpermitted deck is still a legal violation. The risks: insurance will deny claims if the deck collapses and causes injury, the property disclosure form requires you to disclose the unpermitted work when selling (and buyers will demand price reductions or repairs), and a lender may refuse to refinance or provide a home equity loan. The deck itself may be fine, but the legal and financial exposure is severe.

How deep do deck footings need to be in Round Lake Beach?

All deck footings in Round Lake Beach must be dug to a minimum of 42 inches below finished grade to reach below the frost line. This prevents frost heave (upward movement of the footing in winter) from causing the deck to settle and separate from the house. The footing must sit on at least 4 inches of concrete below the frost line. The Building Department will require a footing pre-pour inspection to verify depth before you pour concrete.

Do I need a separate permit for electrical outlets on my deck?

Yes. Deck electrical work requires a separate electrical permit from Round Lake Beach's Building Department. All outdoor outlets must be GFCI-protected, and buried wire must run in PVC conduit at least 6 inches deep (12 inches if it crosses a driveway). Hire a licensed electrician to pull the electrical permit; the city will not accept homeowner-pulled electrical permits for wiring work. The electrical permit typically costs $50–$100 and adds 1–2 weeks to the review timeline.

What happens if I build a deck and then the city finds out there was no permit?

Round Lake Beach's Building Department will issue a stop-work order and may impose a fine of $500–$1,000. You will be required to obtain a permit retroactively, submit plans (or have the existing work inspected), and pay the permit fee. If the deck does not meet current code, you may be required to tear down and rebuild sections (e.g., re-dig footings to 42 inches, add flashing to the ledger). This is much more expensive and disruptive than obtaining a permit before you start.

Can I use pressure-treated wood, composite, or vinyl for a deck in Round Lake Beach?

Yes, all three materials are code-compliant. Pressure-treated (PT) lumber is the most common and least expensive; it requires treatment to UC4B or UC4A standards for ground contact. Composite (wood-plastic blend) is more durable and requires less maintenance but costs more ($15,000–$25,000 for a 12x16 deck). Vinyl is the most expensive and is rare for residential decks. Your permit plan can specify any of these; the Building Department does not require one material over another. If the deck is in a historic district, the Historic Preservation Commission may have restrictions on color or material appearance.

How long does the Round Lake Beach permit review process take?

Plan review for a typical attached deck takes 2–3 weeks if your drawings are complete and correct. The city has moved to online-only filing, so there is no option for over-the-counter (same-day) approvals. If the city identifies corrections needed (most commonly, inadequate ledger-flashing detail or missing footing depth confirmation), they will email a list and you will resubmit. Resubmitted plans are reviewed within 5–7 business days. After approval, you have 180 days to start work before the permit expires.

Does my HOA need to approve my deck in addition to the city permit?

If you live in an HOA community in Round Lake Beach, yes, the HOA's architectural or design-review committee typically must approve the deck separately from the city permit. HOA approval can take 1–4 weeks and may impose restrictions on size, color, materials, or railings. Check your HOA bylaws and contact the HOA board before you submit to the city. Obtain HOA approval first; then submit to the city. If the city and HOA have conflicting requirements, the city's building code takes precedence, but the HOA may still enforce its rules against you.

What inspections will the city require during deck construction?

Round Lake Beach requires three primary inspections: (1) footing pre-pour inspection (before you pour concrete, to verify the holes are 42 inches deep and positioned correctly), (2) framing inspection (after the ledger is bolted, beam and posts are set, and joists are installed — the inspector will check ledger connection, beam-to-post connections, and joist spacing), and (3) final inspection (after stairs, guardrails, and deck surface are complete). The inspector will verify guardrail height (36 inches minimum), stair geometry (10-inch treads, risers ≤7.75 inches), ledger bolts (16 inches on center), and that the deck is not overloaded or unsafe. You must call at least 24 hours before each inspection.

If I add a roof or cover to my deck, do I need a new permit?

Yes. A roof or permanent cover transforms the deck into an enclosed or semi-enclosed structure, which triggers structural and potentially zoning review. A covered deck may count toward your lot coverage (setback and zoning restrictions), and a roof adds dead load to the posts and footings, which may require deeper footings or larger beams. Call the Round Lake Beach Building Department before you design a cover; you may need to submit a new plan, and the project may trigger additional permits or zoning variances.

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 Round Lake Beach Building Department before starting your project.

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