What's Included in
a Roof Replacement?
A complete roof replacement includes: tear-off of the existing system, sheathing inspection and repair, ice-and-water shield, synthetic underlayment, starter strip, field shingles, ridge cap, drip edge, all flashing (chimney, valleys, pipe boots, skylights), ventilation components, and debris removal. Gutters and fascia are optional add-ons. Any quote that doesn't explicitly list all of these is cutting something.
Most homeowners getting quotes for the first time have no framework for evaluating what they're actually being offered. This guide walks through every component of a proper roof replacement — what it is, what it does, and what separates quality installation from the minimum. By the end, you'll know exactly what to look for in any quote you receive.
A Roof Is a System — Not Just Shingles
The biggest misconception homeowners bring to the replacement conversation is that "replacing the roof" means replacing the shingles. Shingles are the visible surface layer — but a properly replaced roof replaces or verifies every component of a multi-layer system, from the structural decking up. When a contractor omits any of these components, they're cutting cost somewhere the homeowner can't see — and that shortcut will produce a failure point that a properly installed system wouldn't have.
The eight components below make up a complete residential roofing system. A full roof replacement from us includes all of them as standard — nothing à la carte on the critical path. The items in the Optional Add-Ons section are discussed separately because they're genuinely situation-dependent.
What does each component cost? See our full cost guideSeals the peak; completes wind resistance; rated to match field shingle
Primary weather barrier; UV protection; granule coating; 25–30 yr rated
Prevents blow-off at first course; directs water off the fascia
Temporary and secondary water barrier over the full deck surface
Self-adhering membrane at eaves, valleys, and penetrations — primary ice dam defense
Metal transitions at every penetration and plane change — the most common leak source
OSB or plywood substrate; inspected and replaced as needed at tear-off
Structural framing — not replaced, but inspected; defects documented
Tear-Off and Deck Preparation
Complete Tear-Off — Not a Layover
A proper replacement removes all existing shingles, underlayment, and deteriorated flashing down to the bare decking. This is not optional — it's the only way to inspect the sheathing, ensure a flat nailing surface, and install ice-and-water shield in full contact with the deck. Illinois building code allows a second layer of shingles over an existing layer, but most roofing professionals advise against it for residential work, and it voids most manufacturer full-system warranties. Every full replacement we perform is a complete tear-off.
Layover red flag: A quote that's significantly cheaper than others and doesn't specify tear-off is almost certainly quoting a layover install. Ask directly.
Sheathing Inspection — Every Square
Once the old system is off, the decking is inspected across the entire roof surface. We're looking for soft spots, rot, delamination, and areas where prior water infiltration has compromised the sheathing. On older DuPage County homes — particularly 1980s–1990s builds — it's common to find 2–6 sheets of deteriorated OSB or plywood, especially at valleys, around chimneys, and along eaves where ice dam action has pushed water under prior flashing. Replacing deteriorated sheathing before installing the new system is not optional — it's why the tear-off exists.
Sheathing Replacement — Per-Sheet Allowance
Standard roofing contracts include a per-sheet allowance for replacement decking — typically 2–3 sheets — with additional sheets priced at a per-unit rate. This is normal and expected; no contractor can know how many sheets have failed until the old system is removed. What to watch for in your quote: a contract that includes zero sheathing allowance is either assuming perfect decking (almost never accurate on roofs over 15 years old) or planning to install over damaged decking without disclosure. Our contracts specify the allowance, the per-sheet overage rate, and the inspection documentation process.
Debris Removal and Site Protection
A complete roof replacement generates 1–3 tons of debris. Full-scope work includes: ground tarps or plywood to protect landscaping, a rooftop dump chute or staged dumpster, magnetic nail sweep across the entire property after completion, and full disposal of all materials. This is included in every contract we write — it's not a line item you should be negotiating. Any contractor who quotes disposal as an add-on is structuring the quote to look cheaper than it is.
Modern construction uses 7/16" or 1/2" OSB (oriented strand board) as standard sheathing — it's code-compliant, structurally equivalent to plywood for roof applications, and significantly cheaper. If your home has original plywood decking, replacement sheets will typically be OSB unless you specifically request plywood matching at an additional cost. Both perform equivalently when properly installed with adequate ventilation — the failure mode for either is moisture infiltration, not material type.
Get a Line-by-Line Replacement Quote
Tear-off, decking inspection, underlayment, ice-and-water shield, flashing, shingles, ventilation — see exactly what you're paying for.
Ice-and-Water Shield and Synthetic Underlayment
The underlayment system sits between the decking and the shingles — invisible once installed, but the last line of defense if a shingle fails. In Illinois, it's also the primary defense against ice dam infiltration. This is where quality contractors differentiate themselves from minimum-compliant ones.
Ice-and-water shield is a self-adhering modified bitumen membrane — it bonds directly to the decking and seals around nails, so even if water gets under a shingle, it cannot pass through into the structure. Illinois code requires it at all eaves (minimum 24" from the wall or 24" past the exterior wall, whichever is greater) and at all valleys. Better installation extends it further: around all penetrations, at all rake edges, and up any wall-to-roof transitions.
36"–48" up from the eave edge (IL code minimum is 24" past exterior wall). The extra width protects against larger ice dam formations, which on DuPage County homes with 18"–24" overhangs can back up 3–4 feet up the slope.
Ice-and-water shield runs the full length of every valley, minimum 18" each side of the centerline. Valleys concentrate water flow from two slopes — they're the highest-volume drainage point and the most vulnerable to freeze-thaw infiltration.
Around every chimney, skylight, dormer, and vent penetration — a 12"–18" band of ice-and-water shield under the flashing provides the adhesive backup that makes those joints watertight even if the flashing metal shifts in a freeze cycle.
Synthetic underlayment covers the entire deck surface not covered by ice-and-water shield — typically 60–80% of the total area. It's the secondary water barrier: if a shingle blows off or fails, the underlayment provides temporary protection until repairs can be made. Quality matters here: standard 15 lb. felt paper is code-compliant but tears easily during installation and has poor UV resistance if temporarily exposed. Synthetic underlayment is 4–5Ã more tear-resistant, lays flatter, and maintains integrity through the typical 1–3 day window between deck prep and shingle installation.
The underlayment system is where budget quotes cut corners most often. Felt paper instead of synthetic saves roughly $0.04–$0.08 per square foot — a $400–$800 difference on a typical DuPage County roof. That saving comes at the cost of installation quality and secondary protection performance. Ask every contractor which underlayment product they spec, and ask whether it's required for the warranty they're offering.
Ask What's Really Included in Your Quote
New ice-and-water shield, new flashing, new pipe boots — every time. Ask any other quote what it reuses.
Shingles, Starter Strip, Drip Edge, and Ridge Cap
Four distinct components make up the visible portion of your roof system — and all four are replaced in a proper installation. Each has a specific job. Omitting or downgrading any of them compromises the system even if the shingles themselves are premium.
Field Shingles
The primary weather surface covering the full deck area. Architectural (dimensional) shingles are standard — they use a two-layer laminated construction that provides a 3D profile, better wind resistance than 3-tab, and a 25–30 year manufacturer rating. Class 4 impact-resistant versions use a polymer-modified mat that resists hail bruising and extends IL-adjusted lifespan by 4–5 years.
Full shingle guideStarter Strip
A pre-made adhesive-strip shingle installed along the eave and rake edges before the first course of field shingles. The adhesive strip on the starter aligns with the exposure on the first course of field shingles — creating a sealed bond at the most wind-vulnerable point on the roof. Without starter strip (or when a contractor cuts field shingles to serve as starters), the first course has no bonded backup and is the most likely blow-off point in a wind event. This is a common corner-cut on budget installations.
Drip Edge
A metal L-flashing installed along the eave and rake edges before the underlayment (at eaves) and over the underlayment (at rakes). It directs water away from the fascia board and into the gutter rather than running back under the shingles by capillary action. Illinois building code requires drip edge on all new installations. Budget quotes that omit drip edge — or reuse corroded existing drip edge — are skipping a code-required component. Fascia rot from missing drip edge is one of the most common avoidable repair items we find on older roofs.
Ridge Cap Shingles
Pre-formed three-tab caps installed at all ridges and hips. Purpose-made ridge cap is thicker than cut field shingles, has its own adhesive strip, and is tested to the same wind rating as the field shingle. Many budget installers cut 3-tab or architectural shingles into hip-and-ridge pieces — this is cost cutting that reduces wind resistance and often voids the manufacturer warranty on the field shingle. GAF's full-system warranty requires factory hip-and-ridge cap, not cut-down field shingles.
Every quote should specify the exact product name and line, not just "architectural shingles" or "30-year shingles." GAF Timberline HDZ and GAF Timberline ArmorShield II are both architectural shingles with 30-year ratings — but the ArmorShield II is Class 4 impact-resistant and costs ~$1.20–$1.80 more per square foot installed. A quote that says "architectural shingles" without a product name may be bidding a builder-grade product that doesn't qualify for the warranty tier being advertised. Ask for the specific product line before comparing quotes.
Flashing — Every Penetration, Every Transition
Flashing is the metal transition material at every point where the roof plane meets a vertical surface, a valley, or a penetration. It is responsible for more roof leaks than any other single component — not because it fails often, but because improper installation or reuse of old flashing is the most common shortcut in residential roofing. Every piece of flashing should be new on a complete replacement.
Chimney Flashing
The most complex flashing assembly on a residential roof — a two-part system of step flashing (individual pieces woven with each course of shingles) and counter-flashing (embedded or surface-applied to the chimney masonry). The mortar joint where counter-flashing meets the chimney is the primary failure point on older systems, driven by the differential thermal movement between the masonry chimney and the wood-framed roof. Illinois's freeze-thaw cycling accelerates this joint cracking significantly. On a complete replacement, all chimney flashing — step and counter — is replaced new.
Valley Flashing
Valleys are where two sloping planes meet and concentrate water flow from both sides — they carry more water per linear foot than any other part of the roof. Open metal valley (W-metal or V-metal running the full length) is the most durable approach and the standard for Illinois climates. Closed-cut and woven valley installations use shingles rather than metal — they're aesthetically cleaner but carry higher long-term leak risk as the shingle material at the valley centerline deteriorates faster from concentrated flow. Valley flashing is always replaced new on a complete tear-off.
Pipe Boot Collars
Every plumbing vent stack, HVAC penetration, and similar round penetration through the roof requires a pipe boot — a rubber-gasketed flashing collar that seals around the pipe. Neoprene pipe boots have a practical lifespan of 10–15 years in Illinois UV conditions before the rubber collar cracks and begins admitting water. On a complete replacement, all pipe boots are replaced new. A contractor who proposes reusing existing pipe boots on a new shingle installation is creating a near-certain leak point within 5–8 years. There is no acceptable reason to reuse a pipe boot on a full replacement.
Skylight Flashing
Skylights require a full perimeter flashing kit — step flashing on the sides, a sill flashing at the bottom, and a head flashing at the top, all integrated with the ice-and-water shield below. Velux and FAKRO both supply purpose-built flashing kits matched to each skylight model; these should be used over generic flashing on any skylight replacement or new installation. If your home has skylights, the skylight flashing is addressed as part of the roof replacement scope — either the existing flashing is replaced new if the skylight is in good condition, or the full skylight is replaced if the curb or glass has deteriorated.
Dormer and Wall Flashing
Where a vertical wall (dormers, second-floor additions, attached walls) meets a sloping roof, step flashing is woven into the shingle courses up the sidewall and covered with a continuous counter-flashing strip. This is one of the most detail-intensive parts of a roof installation and one of the most common sources of callbacks on budget projects. On homes with multiple dormers — common in Naperville's 1990s–2000s colonial stock — dormer flashing constitutes a significant labor component of the total replacement scope.
Vent and Fan Flashings
Attic exhaust vents, power attic ventilators, and range hood vents all require purpose-built flashing units — not generic pipe boots. Each has a specific flashing collar matched to the penetration diameter and angle. Bath fan and range hood vents terminating through the roof (rather than through a soffit or wall) are frequently found with improper flashing on DuPage County homes — a common detail error from original construction that produces slow chronic leaks rather than obvious flooding. All are replaced new on a complete replacement.
Some contractors propose reusing existing flashing — particularly chimney counter-flashing — when it "looks good." On a 15–20 year old roof, all galvanized steel flashing has been through 15–20 years of freeze-thaw cycles and has varying degrees of corrosion, sealant deterioration, and metal fatigue that's not visible from a ladder inspection. Reusing it means the new shingle warranty period — 25–30 years — will be backed by flashing that's already a decade or more into its own service life. We replace all flashing as standard practice on every complete replacement. Any quote that proposes reusing existing flashing should explain exactly which components, why, and how they'll address the warranty implications.
Ventilation — Included in the Replacement, Critical to the Lifespan
Ventilation components — ridge vents, soffit vents, box vents, and power attic ventilators — are part of the roofing system even though they're sometimes treated as a separate trade. On a complete replacement, ventilation is assessed, corrected if deficient, and new components are installed as part of the scope. Proper attic ventilation is actually a warranty requirement for GAF's full-system coverage: installing a new roof over an under-ventilated attic voids the shingle performance warranty because the elevated attic temperatures are a known lifespan compressor.
Illinois code specifies a minimum ventilation ratio of 1 sq ft of net free ventilation area per 150 sq ft of attic floor area (reducible to 1:300 with a balanced ridge-to-soffit system). Many 1980s–1990s DuPage County homes fall short of this — particularly homes where ridge vents were retrofitted without corresponding soffit ventilation increases, which creates negative pressure rather than the intended convection flow.
How ventilation affects roof lifespanA continuous vent running the full length of the ridge, installed under the ridge cap shingles. Provides the exhaust function for the attic air circulation system. The existing ridge vent is removed with the old shingles and replaced new — both to ensure integrity and because ridge vent products have improved significantly over the past decade. Shingle-over ridge vents (GAF Cobra® series) are the current standard; they're more effective and less visible than older external ridge vent profiles.
Soffit vents are the intake side of the ventilation system. They're not typically replaced as part of a roofing project (they're on the soffit, not the roof surface), but their free area is confirmed and documented during the replacement assessment. If insulation at the eave is blocking soffit intake — a common condition in older DuPage County homes — it's noted in the inspection report as a condition that needs correction for proper system performance.
Homes with box vents (individual roof penetrations for exhaust) or power attic ventilators (PAVs) have these components replaced new as part of the scope. PAVs are a topic of some debate — when properly balanced with adequate soffit intake, they're effective; when the soffit intake is insufficient, they create negative pressure that can draw conditioned air from the house into the attic. We document the ventilation balance calculation and provide a recommendation if PAV performance is a concern.
Optional Add-Ons Worth Considering at Replacement Time
These components are not part of every replacement scope — but replacement day is the most cost-effective time to address them, because the labor mobilization is already on site and the roof is already off. Each one is dramatically cheaper done simultaneously than as a separate project.
Gutters are removed and reinstalled to accommodate drip edge installation on a roof replacement. This is the ideal moment to assess gutter condition and replace them if needed — the labor overlap is significant, and a new roof paired with failing gutters is a setup for fascia damage within 3–5 years. Seamless aluminum gutters are standard; K-style profile is the most common in our market. Add-on cost at replacement time is typically $800–$2,400 for a full set depending on linear footage.
Full gutter installation guideIf your home has skylights, they need to be addressed as part of the replacement scope regardless — the flashing around them is replaced, and this is the moment to assess whether the skylight unit itself should be replaced. Velux and FAKRO insulated glass skylights have a seal lifespan of 15–20 years; a fogged or failed skylight installed new at the same time as the roof gets the benefit of the existing mobilization and a clean integration with the new underlayment system.
Full skylight installation guideDeteriorated fascia boards — typically from years of missing or failed drip edge — are addressed at replacement time when the gutters are removed and the eave is accessible. Soft or punky fascia compromises the gutter attachment and the drip edge seal. This is a carpentry component, not strictly roofing, but it's almost always handled as part of the replacement scope because the access is already staged. Cost varies significantly by extent of damage found.
What a Complete Replacement Quote Must Include — and the Red Flags That Mean Cut Corners
| Line Item | What to Confirm |
|---|---|
| Complete Tear-Off | Explicitly stated — not "over existing shingles" |
| Sheathing Allowance | Min. 2 sheets included; per-sheet overage rate disclosed |
| Ice-and-Water Shield | Specific product name + coverage zones stated |
| Synthetic Underlayment | Product name — not "felt" or "tar paper" |
| Field Shingles | Exact product name, line, color, and warranty tier |
| Starter Strip | Named product — not "cut field shingles" |
| Drip Edge | New — not "reuse existing" |
| Ridge Cap | Purpose-made cap — not cut field shingles |
| All Flashing — New | Every pipe boot, chimney, valley, wall — all new |
| Ridge Vent | New shingle-over type replacing existing |
| Permit | Pulled by contractor — not your responsibility |
| Full Debris Removal | Haul-off + magnetic nail sweep included |
A quote 20–35% below comparable bids is almost never an efficiency advantage — it's a scope reduction that's not stated plainly. Ask them to match every line item to the spec above and the gap will become visible.
All DuPage County municipalities require a permit for roof replacement. A contractor who proposes working without one is either unaware of local code (concerning) or deliberately avoiding the inspection that the permit triggers (more concerning). An unpermitted roof can create problems at resale and may void insurance claim eligibility for future damage.
Standard industry practice is a deposit (typically 10–30%) at contract signing and the balance at completion or after final inspection. Full upfront payment eliminates your leverage and is a common pattern with storm-chaser contractors who won't be available for warranty claims.
GAF's Golden Pledge® warranty — the highest available — can only be issued by GAF Master Elite® certified contractors. If a contractor offers "30-year warranty" without being Master Elite® certified, they're describing the manufacturer's material warranty that any homeowner gets, not the enhanced workmanship coverage that requires certification. Ask specifically: are you GAF Master Elite® certified? We are.
Storm chasers — contractors from out of state who follow major weather events — are prevalent in the DuPage County market after every significant hail event. They're often not licensed in Illinois, carry inadequate insurance, and will not be available for warranty service. Illinois law requires roofing contractors to be licensed; ask for the license number before any discussion proceeds.
Our free estimate covers every line item on this checklist. No vague "architectural shingles" — specific products, specific quantities, specific warranty tier.
What's Included in a Roof Replacement — FAQ
Is gutters included in a roof replacement?
Gutters are not included in a standard roof replacement scope — they're a separate system. However, gutters are removed and reinstalled as part of the replacement process (to allow drip edge installation), and replacement day is the most cost-effective time to replace them if they're aging or failing. We offer gutter replacement as an add-on to every roof replacement project. If your gutters are 15+ years old, have pitch issues, or are showing joint failures, it's worth discussing at the estimate. See our full gutter installation page.
Does a roof replacement include the fascia?
Not as standard scope, but deteriorated fascia is addressed when found during the tear-off and eave inspection. Fascia replacement is a carpentry component that's most cost-effective to do at the same time as a roof replacement, because the gutter is already removed and the eave is fully accessible. We include fascia repair as an add-on at a disclosed per-linear-foot rate. Homes with prior missing or failed drip edge often have fascia damage from water runback — this is identified during the tear-off and communicated to the homeowner before any additional work proceeds.
Will the roofer replace the plywood/OSB decking?
Yes — any deteriorated sheathing found during the tear-off is replaced before the new system goes down. Standard contracts include an allowance of 2–3 sheets and disclose the per-sheet rate for any overage. The extent of sheathing replacement isn't known until tear-off, which is normal and expected. What's not acceptable is a contractor who installs over damaged decking without disclosure or who includes a $0 sheathing allowance without specifically confirming the deck is in perfect condition. On our projects, we photograph all decking requiring replacement before installing anything over it, and we show the homeowner or provide photos before proceeding.
What's the difference between the material warranty and the workmanship warranty?
The manufacturer's material warranty — 25–30 years for standard architectural shingles — covers defects in the shingle product itself: premature granule loss, manufacturing defects, abnormal weathering. It does not cover installation errors, flashing failures, or any component not made by the manufacturer. The workmanship warranty covers installation quality and is provided by the contractor. GAF's Golden Pledge® warranty is the highest tier available — it extends the manufacturer's material coverage to 50 years and adds workmanship coverage for up to 25 years, but it can only be issued by GAF Master Elite® certified contractors. We carry this certification and offer Golden Pledge® on qualifying installations.
How long does a full replacement take?
A typical residential roof replacement on a DuPage County home (1,500–3,000 sq ft living area, 20–35 squares of roof area) is completed in one day for most installations. Homes with significant complexity — multiple chimneys, skylights, steep pitch, or extensive dormer systems — may run into a second day. Sheathing replacement adds time depending on extent. We schedule projects to allow completion before nightfall on day one to avoid leaving any open deck exposed overnight. For a full timeline breakdown, see our roof replacement timeline guide.
Do I need to be home during the replacement?
You don't need to be home for the full day, but we recommend being available by phone and present at two points: at the start of the day for a walkthrough of any access considerations or specific concerns, and at the end for a final walkthrough before payment. If sheathing replacement is found and needed, we contact you (or text photos) before proceeding past the allowance in the contract. Our crew lead is on-site throughout and handles all day-of coordination. Interior access is not required.
Our Replacement Quote Covers Every Line Item on This Page
Every component detailed above is included as standard in our full replacement scope — no upsells on ice-and-water shield, no felt paper substitute for synthetic underlayment, no reused pipe boots. GAF Master Elite® certified. 100% permit pass rate across all DuPage County jurisdictions. 20+ years serving the area.