Do I need a permit for roof replacement in
Montgomery, Illinois?

Montgomery roof replacement permits — the key details

The centerpiece of Montgomery's enforcement is IRC R907.4, which prohibits more than 2 layers of roof covering on a building. In practice, this means if a roofer uncovers 3 layers during a tear-off or if an inspector spots evidence of 3 layers (visible edge at the rake, multiple nailing patterns), the job stops until the roof is stripped to the deck. Montgomery Building Department takes this seriously because multi-layer roofs trap moisture, void manufacturer warranties, and hide deck rot. When you apply for a permit, you'll be asked how many layers currently exist; if you answer 2 and the roofer finds 3, you must stop, remove all layers, and get a re-inspection of the bare deck (typically $50–$100 additional inspection fee). This requirement applies to all roofing materials — shingles, architectural shingles, and composition — equally. Some homeowners and inexperienced roofers don't realize the city requires a permit just to uncover the roof; skipping the permit in hopes of a quick overlay is the most common violation in Montgomery.

Material changes — moving from asphalt shingles to metal, tile, or slate — require explicit permit notation and may trigger a structural evaluation if the new material is significantly heavier (tile and slate can add 8–15 pounds per square foot). IRC R905.10 (metal roofing) and R905.11 (slate/tile) set fastening and underlayment specs that differ sharply from shingle work. For example, standing-seam metal requires specific fastener types and spacing; tile requires a solid or ventilated nailer deck and ice-and-water shield under the battens. Montgomery's inspectors will ask for product data sheets (from the shingle or metal manufacturer) and a fastening schedule; missing these documents is a common reason for plan-review rejections. If you're changing material, budget 5–7 extra business days for permit approval because the plan checker will review the structural load and fastening details. Material upgrades (e.g., architectural shingles to premium architectural) that don't change weight or fastening are lower risk, but still need a permit if the project scope is >25% of roof area or includes any tear-off.

Ice-and-water shield is non-negotiable in Montgomery's Zone 5A climate. IRC R905.1.1 requires it to extend at least 24 inches from the eave on low-slope roofs and 24 inches up from the inside face of an exterior wall on high-slope roofs to prevent ice dam damage. The permit application and the roofer's submittal must specify the brand and extent of shield (e.g., 'Titanium UDL or approved equal, 24 inches from eave, full width'). Inspectors will check the shield during the in-progress inspection and again at final — it's a line-item on the punch list. Using cheaper, thin-gauge ice-and-water or skipping it entirely is a common way permits are rejected or flagged during inspection. This is also where homeowners get burned: a roofer may promise to 'handle ice dam protection' verbally but not specify it in writing on the permit documents, leading to a re-do after inspection.

Underlayment specs are equally detailed. Standard asphalt-shingle reroofs require either synthetic underlayment (e.g., 30#-equivalent weight) or 15# roofing felt; Montgomery Building Department requires it to be called out by product name on the permit. For example: 'Underlayment: Titanium or approved synthetic, 30# equivalent, full coverage, wrapped at eaves per IRC R905.2.8.' Metal roofing typically requires a premium underlayment (synthetic or premium felt) with specific fastening to the deck. Tile and slate require full ice-and-water or premium underlayment with nailing battens. If your permit submittal says 'standard underlayment' without naming a product, plan on a request for information (RFI) that delays approval 3–5 days.

The permit inspection sequence in Montgomery is straightforward for straightforward projects. Once the permit is issued (typically 1–2 business days for a like-for-like shingle-to-shingle roof), the roofer can begin work. An in-progress inspection (called mid-point or rough-in by some jurisdictions) is scheduled once the deck is exposed and ready for underlayment. The inspector checks for hidden damage, rot, or structural issues that require repair before covering. A final inspection occurs after the shingles, flashing, and underlayment are complete; the inspector verifies fastening patterns, ice-and-water shield placement, flashing detail at valleys and penetrations, and proper venting (if applicable). Both inspections are typically scheduled 24 hours in advance by phone or through the online portal. Expect each inspection to take 20–40 minutes. Plan on 5–7 working days from permit issuance to final sign-off for a straightforward re-roof; multi-day delays are common if deck repair is needed or if weather pauses the work.

Three Montgomery roof replacement scenarios

The 3-layer trap: why Montgomery cracks down on multi-layer roofs

Montgomery and most Illinois municipalities strictly enforce the IRC R907.4 prohibition on roofs with more than 2 layers of covering. The rule exists for three reasons: (1) moisture can become trapped between layers, leading to accelerated rot and structural decay; (2) nailing patterns become hard to verify, increasing risk of fastener failure in wind or ice events; (3) manufacturer warranties (usually 25–30 years) are void on roofs with more than 1 layer underneath, so the homeowner loses recourse if the shingles fail early. In practice, many older Montgomery homes (built 1975–1995) have 2 or even 3 layers because re-roofing costs used to be lower if you just nailed over the old shingles.

When you apply for a permit in Montgomery, the form asks 'Number of existing layers?' If you answer 2, you're free to overlay (though the city still prefers tear-off for quality and to avoid future problems). If you answer 3 or if the roofer uncovers a 3rd layer, you must stop and tear off all layers. The city's building department treats 3-layer discovery as a mandatory halt — the roofer can't continue, and a new inspection must be scheduled once the roof is down to the deck. This has caught many DIY-minded homeowners and fly-by-night roofers. A typical scenario: a homeowner gets a cheap quote from a roofer who claims 'we'll just nail over it,' work starts, a layer is found, city is called, work stops, permit is retroactively required, back-fees are owed, and the roofer disappears. Montgomery Building Department estimates that 30–40% of unpermitted roof complaints in the city stem from the 3-layer violation.

To avoid this trap, always disclose the number of layers honestly on the permit application, and ask your roofer to verify the layer count before quoting. If layers are unclear, request a small area (2–3 sq ft) be opened during the pre-work walk-through so you and the roofer can count together. Most professional roofers in Montgomery are familiar with the rule and budget tear-off labor accordingly. If a roofer suggests 'we'll just nail over it and hope no one checks,' find a different roofer.

Ice-and-water shield in Zone 5A: why Montgomery inspectors verify it

Montgomery straddles the border between climate zones 5A (north) and 4A (transitional south), with frost depth at 42 inches north of I-88 and closer to 36–40 inches south. This means ice dams are a real hazard November through March. IRC R905.1.1 requires ice-and-water shield (also called ice-and-water barrier or self-adhering underlayment) to extend 24 inches from the eave on all pitched roofs in zones 4 and above. The shield prevents meltwater seeping under shingles from traveling up the roof and backing into the attic or wall cavity during freeze-thaw cycles.

Montgomery inspectors specifically check for ice-and-water shield extent and product quality during the in-progress and final inspections. Common failures: (1) roofer installs shield but only 12 inches from the eave (not 24); (2) shield is installed but a cheap, thin-gauge product that fails within 3 years (city prefers brand-name products like Titanium UDL, Grace Ice and Water, or equivalent); (3) shield is omitted entirely with the excuse 'we'll use felt and caulk instead' (not permitted in Montgomery). If an inspector finds shield missing or undersized, the permit goes 'on hold' until it's corrected and re-inspected.

From a homeowner's perspective, this is actually good news: the city is enforcing a rule that protects your attic and framing. Budget $150–$250 extra for ice-and-water shield on a standard re-roof (material + labor). It's a low-cost insurance policy against ice dam damage, which can cost $3,000–$10,000 to repair. If a roofer quotes without ice-and-water shield, ask why — in Montgomery's climate, it's not optional.

Common questions