Updated October 2026 by Chris Horton. A method for reading two architectural-shingle bids against each other, not a verdict on shingle brands or contractors. How we estimate costs
Two roofers quote the same house. Both proposals name an architectural shingle, sometimes the same product line in the same color, and the totals are far apart. The instinct is to call one contractor expensive. The more useful question is what each bid does around the shingle: whether it tears off to the deck, what it assumes about the wood underneath, what goes down before the shingles, which flashings are new and which are reused, how the attic breathes, and which warranty conditions the work is built to meet. The shingle is one layer of a roof system. This page decodes the rest of the bid.
Is this the right decoder for your bids?
This page assumes both bids propose asphalt architectural shingles, also sold as laminated or dimensional shingles. If one bid is for shingles and the other is for metal, the gap is a material and system choice, and the asphalt vs metal roof quote decoder is the right starting point. If both bids are for standing seam metal, use the standing seam roof quote decoder instead. This page covers the case neither of those handles: two shingle bids that look alike on page one and still price different projects.
If you only have one bid so far, start with the roof replacement quote checklist. If you have not settled whether the roof needs replacing, roof repair vs replacement comes first.
Same shingle line, different roof
“Architectural shingles” is a category, not a product. The major manufacturers each sell several architectural lines under one brand, at different weights, looks, wind ratings and warranty terms. A bid that says only “architectural, 30-year” or “lifetime architectural” names neither a manufacturer nor a line, so it cannot be checked against any installation instruction or warranty document. That is the first gap to close, and it is the one most homeowners already notice.
The bigger gap is everything else. Shingle manufacturers define their own warranty tiers around a system of matched parts, not around the shingle alone, which is the clearest sign that two roofs with the same shingle on top can be different roofs underneath:
- GAF’s Roofing System Limited Warranty conditions its system coverage on LayerLock-labeled GAF shingles plus at least four qualifying GAF accessories: ridge cap shingles, starter strip shingles, a roof deck protection product, and either a leak barrier or an attic ventilation product. GAF’s Golden Pledge tier additionally requires a GAF Master Elite contractor and five qualifying accessories, adding both leak barrier and attic ventilation.
- Owens Corning’s warranty page lists hip and ridge shingles plus two other Owens Corning components for its System Protection tier, and hip and ridge, underlayment plus two other components for its Preferred and Platinum Protection tiers, which also require installation by a Preferred or Platinum contractor.
- CertainTeed says its SureStart PLUS extended coverage is available when an Integrity Roof System is installed by a CertainTeed-credentialed contractor.
So two bids can name the same shingle and still differ on whether the starter, ridge cap, underlayment, leak barrier and ventilation come from the same manufacturer, whether the installer holds the credential a tier requires, and therefore which warranty document the homeowner ends up with. None of that shows in the shingle name.
If both of your bids name GAF Timberline HDZ, the GAF Timberline HDZ quote decoder works through that line’s accessories, installation assumptions and GAF warranty documents bid against bid.
These manufacturers are named as examples of documentation a bid can be checked against, not as recommendations, and their requirements apply to their own products only. Warranty tiers and conditions change. The document that settles a question about your roof is the current warranty and installation instruction for the exact product line on your bid.
Five words for every line on the bid
Before comparing anything, read each scope line on each bid into one of five statuses. The statuses are what make two bids comparable, because they force a blank or a vague phrase to show up as a blank.
| Status | What the bid actually says | Example wording |
|---|---|---|
| Included | The item is installed new, and the price covers it. | “Install new step flashing at all roof-to-wall intersections.” |
| Reused | An existing component stays in place or is removed and put back, and the price covers the labor around it, not a new part. | “Existing chimney counterflashing to remain; reseal.” |
| Allowance | A stated quantity is included, and anything beyond it is charged at a stated unit price. | “Includes up to a stated number of sheets of deck replacement; additional sheets at the unit price shown.” |
| Excluded | The bid says the item is not part of this price. | “Skylights, gutters and permit fees not included.” |
| Unspecified | The bid is silent, or uses a phrase with no quantity, location or product. | “Flash as needed.” “Ice and water per code.” “Vents as required.” |
Reuse vs replace is a different question from included vs excluded
Homeowners often read “reuse” as “left out of the job.” It is not the same thing. Included or excluded answers whether the work is inside this price. Reused or replaced answers whether the part on your roof afterwards is new or old. A reused flashing can be fully inside the price, with labor to lift, clean, refasten and seal it. An excluded flashing stays on the roof too, but nobody has agreed to do anything with it. The four combinations below are four different bids.
| Same step flashing, four ways to bid it | Inside the price? | New or existing part afterwards? | Status to record |
|---|---|---|---|
| “Replace all step flashing with new.” | Yes | New | Included |
| “Reuse step flashing where serviceable; replace damaged pieces at the unit price shown.” | Yes, plus a priced allowance | Mostly existing, some new | Reused, with an allowance |
| “Existing wall flashing not part of this contract.” | No | Existing, untouched | Excluded |
| “Flashing per code.” | Unclear | Unclear | Unspecified |
Reuse is not automatically wrong. Counterflashing built into a brick chimney or tucked behind siding is often left in place on a reroof because replacing it means opening the masonry or the wall. What matters is that the bid says so, says who decides whether a piece is serviceable, and prices what happens if it is not.
The status words then map onto the four comparison results used across UpgradeWorth’s roofing tools. Both bids with the same status and the same product or detail is Same. Both stated, but differently, is Different. Any Unspecified on either bid is Unknown. And a difference large enough that the two totals are pricing different projects, such as tear-off on one bid and overlay on the other, is Not comparable.
The architectural-shingle system scope matrix
Read both bids into the matrix line by line. Write a status for each bid next to each line. Any Unspecified goes on the list of questions to send back before you look at totals.
1. Removal and deck
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Removal method | Tear-off to the deck, or an overlay over the existing roof, in so many words. | Unspecified. | Tear-off on one bid and overlay on the other. See the tear-off and deck decision flow. |
| Existing layers | How many layers are assumed, whether that was confirmed, and the unit price per extra layer. | Unspecified, or an assumption with no price for being wrong. | The bids assume different layer counts. |
| Deck type | Whether the existing deck is solid sheathing or spaced boards, and what will be added if it is not solid. | Unspecified on an older house. | One bid adds sheathing over spaced boards and the other does not mention it. |
| Deck replacement | An included quantity, the sheet material and thickness, and a unit price beyond it. | Allowance with no unit price. “Replace rotted wood as needed.” | Rarely on its own, but an open-ended line can erase any difference between totals. |
| Deck fastening | Whether loose or under-fastened sheathing will be refastened, where the bid or a program it claims calls for it. | Unspecified, only if a bid relies on a program that requires it. | Not on its own. |
2. Underlayment and ice barrier
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Underlayment | The named product (felt or a named synthetic), and that it covers the whole deck. | Unspecified, or a generic word with no product. | Not on its own. A named manufacturer product may count toward a system warranty tier. |
| Low-slope sections | How any section between 2:12 and 4:12 will be underlaid, and whether any section is too flat for shingles at all. | Unspecified where the roof has a shallow section. | One bid shingles a section the other prices as a different low-slope membrane. |
| Ice barrier at eaves | Whether it is installed, the named product, and how far up the slope it runs, tied to the local requirement. | “Ice and water per code” with no distance or product. | Not on its own, but different coverage is a real scope difference. |
| Self-adhered membrane elsewhere | Which valleys, penetrations, walls or low-slope areas get it, if any. | Unspecified. | Not on its own. |
3. Flashing and edges
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Drip edge | New drip edge at eaves and rakes, metal and color, or a stated reason for none. | Unspecified. Reused. | Not on its own. |
| Step flashing at sidewalls | New or reused, at which walls. | Reused with no serviceability rule. Unspecified. | Not on its own; a run of Reused against Included adds up. |
| Chimney flashing | Apron, step, counterflashing and any cricket, each new or reused, and how it is terminated. | “Flash chimney” with no detail. | New flashing and a cricket on one bid against reseal-only on the other. |
| Headwall and kickout | Flashing where a roof meets a wall above it, and a kickout where an eave runs into a wall. | Unspecified on a roof with those intersections. | Not on its own. |
| Valleys | Number of valleys, open or closed method, and the valley lining. | Unspecified. | Not on its own. |
| Pipe boots and vent collars | A count, and new or reused. | Reused. Unspecified. | Not on its own. |
| Skylights | Replaced, reflashed with a new kit, or excluded, named individually. | Unspecified. | One bid replaces skylights and the other excludes them. |
4. Ventilation
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Exhaust | Ridge vent or other exhaust, named, new or reused, and what happens to existing box vents or turbines. | “Vents as required.” | One bid converts to ridge venting and the other reuses existing vents. |
| Intake | Whether existing soffit or eave intake is adequate, and what will be added if not. | Unspecified. | Not on its own. |
| Balance statement | That intake and exhaust have been assessed together for this attic. | Unspecified. | Not on its own, but it affects warranty eligibility on many system tiers. |
5. Shingle and system accessories
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Shingle | Manufacturer, product line and color. | “Architectural” or a year count with no line. | Two different lines can both be legitimate; compare the other lines rather than the brand. |
| Starter | A manufactured starter product at eaves, and at rakes where the bid includes it. | Unspecified, or cut-down field shingles. | Not on its own. |
| Hip and ridge | A manufactured hip and ridge product, or field shingles cut on site. | Unspecified. | Not on its own. |
| Accessory brand match | Which accessories come from the shingle manufacturer, and which warranty tier that combination is meant to qualify for. | Unspecified on a bid that claims an enhanced warranty. | One bid’s tier depends on accessories the bid does not list. |
| Nailing | Nails per shingle and any enhanced pattern a wind rating or warranty depends on. | Unspecified on a bid that claims a wind rating. | Not on its own. |
6. Warranty conditions
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Manufacturer tier | The named warranty tier, with the document attached or referenced. | A year count or “lifetime” with no document. | One bid is built to an enhanced system tier and the other to the standard shingle warranty. |
| Installer credential | The credential the tier requires, checkable on the manufacturer’s own contractor locator. | Unspecified on a bid that claims an enhanced tier. | Not on its own. |
| Registration | Who registers the warranty, and that it happens within the document’s window. | Unspecified. | Not on its own. |
| Workmanship | Years, and who stands behind it: the contractor alone or a manufacturer program. | Unspecified. | Not on its own. |
7. Disposal, permits and terms
| Scope line | A complete bid states | Statuses that need a question | When the totals stop being comparable |
|---|---|---|---|
| Disposal | Dumpster and disposal included, and whether extra layers or heavy debris cost more. | Excluded. Unspecified. | One bid includes disposal and the other excludes it. |
| Permit and inspection | Who pulls and pays for the permit, and whether inspection is included. | Unspecified. | Not on its own. |
| Gutters and edge work | Removed and reset, replaced, or untouched. | Unspecified. | One bid replaces gutters inside the total. |
| Property protection and cleanup | Landscaping protection, nail sweep, final walkthrough. | Unspecified. | Not on its own. |
| Unit prices and change orders | Deck, layer and flashing unit prices, and written approval before extra work. | Unspecified. | Not on its own, but it decides the final invoice. |
| Payment schedule | Deposit, progress and final payments, and what triggers each. | Unspecified. | Not on its own. |
Once each bid is read into the matrix, the compare roof quotes tool and the roof quote analyzer walk the same questions and write the follow-ups out for you. Nothing you type is stored.
Tear-off and deck-condition decision flow
Removal scope is the line most likely to make two shingle totals incomparable, and the deck assumption is the line most likely to change the final invoice. Work through these steps for each bid, in order.
The code references above come from the 2021 International Residential Code, Chapter 9. Jurisdictions adopt different editions and write their own amendments, so the position for your roof is whatever your building department says it is.
Flashing reuse vs replacement checklist
The residential code does not ban reusing flashing outright. The International Residential Code’s reroofing section says existing flashings, edgings, outlets, vents and similar devices that are part of the roof assembly must be replaced where rusted, damaged or deteriorated. Earlier editions worded the same rule as a list naming vent flashing, metal edgings, drain outlets, collars and metal counterflashings. In practice that makes reuse a condition question under the code, and a bid that reuses flashing should say who judges the condition and what happens to a piece that fails.
A manufacturer warranty tier can be stricter than the code. GAF’s Golden Pledge brochure, for example, lists new metal flashing among the tier’s requirements, with exceptions set out in the document. If a bid quotes a tier like that and also reuses metal flashing, ask the contractor to show how the tier’s flashing condition is met.
| Flashing | What “reuse” usually means | What the bid should state |
|---|---|---|
| Drip edge (eaves and rakes) | Leaving existing edge metal in place under new shingles. | New or reused, and if reused, why. The IRC added a drip edge requirement at eaves and rakes of shingle roofs in its 2012 edition, but states amend it: South Carolina, for example, requires it where the shingle manufacturer does. Ask what applies locally. |
| Step flashing at sidewalls | Working new shingles around pieces already woven in at the wall. | New or reused at each wall, and whether siding will be lifted or cut back to replace it. |
| Chimney counterflashing | Leaving the piece set into the masonry and replacing what sits under it. | Whether the counterflashing is reused, reset or replaced, and whether any masonry work is included or excluded. |
| Chimney apron and cricket | Reusing the front apron; leaving a wide chimney without a cricket. | New or reused, and whether a cricket is included where the chimney is wide enough to need one. |
| Headwall flashing | Leaving the existing piece where a roof meets a wall above it. | New or reused. |
| Kickout flashing | Often absent on older houses, so there is nothing to reuse. | Whether one is added where an eave runs into a wall. |
| Valley metal or lining | Reusing open-valley metal. | Valley method, lining and whether metal is new. |
| Pipe boots and vent collars | Reusing rubber boots or metal collars. | A count, and new or reused for each. |
| Skylight flashing | Shingling around existing skylight flashing. | New flashing kit, skylight replaced, or excluded, for each skylight. |
Rubber pipe boots and painted edge metal are where reuse most often runs into the condition rule, and where “reuse where serviceable” most needs a unit price for the pieces that turn out not to be.
Underlayment, ice barrier, ventilation, disposal and permit checklist
A quick pass for the five lines most often left blank on a shingle bid. Tick each one only if the bid says it in writing.
- Underlayment named. A product, not just “synthetic” or “felt.” If a low-slope section is involved, how it is underlaid. The IRC limits asphalt shingles to slopes of 2:12 or steeper and calls for double underlayment from 2:12 up to 4:12.
- Ice barrier located. Where the jurisdiction designates a history of ice damming, the IRC requires an ice barrier for asphalt shingles from the eave edge to at least 24 inches inside the exterior wall line, as the Massachusetts residential code FAQ quotes it. Whether that applies to your house is a local question; the bid should say how far up its membrane runs and why.
- Ventilation described. Intake and exhaust named, with a statement that they were assessed together. Shingle manufacturers tie system coverage to ventilation: GAF lists attic ventilation among its qualifying accessories, and its Golden Pledge tier requires it.
- Disposal in the price. Dumpster, haul-off and any surcharge for extra layers.
- Permit owned. Who pulls it, who pays, and whether the inspection is part of the job.
The bid that names a shingle line and nothing else
Watch for this.
A bid that reads like “Tear off and install [brand] [line] architectural shingles in [color], lifetime warranty” looks specific because a real product is named. It is the least specific shingle bid there is. It leaves the deck assumption, underlayment, ice barrier, every flashing, ventilation, starter, ridge cap, disposal and permit Unspecified, and it implies a warranty tier without showing whether the bid is built to qualify for it. Treat every one of those lines as Unknown, and do not compare its total with a bid that spells them out until it does too.
Do not compare totals yet if any of these is true
Each condition below means the two totals are not yet measuring the same roof. Send the bid back for specification first.
A bid that clears these gates is not necessarily the better bid. It is a bid that has become comparable.
Questions to send back when a line is missing
Copy the questions that match the blanks on your bid and send them in writing. Sending every contractor the same questions makes the answers comparable too.
Removal and deck
- Is this a tear-off to the deck or an overlay? How many existing layers are you assuming, and what changes in price if there are more?
- Is my existing deck solid sheathing or spaced boards, and if boards, is new sheathing in this price?
- How many sheets of deck replacement are included, of what material and thickness, and what is the price per extra sheet? Will I see photos before extra sheets are replaced?
Underlayment and ice barrier
- Which underlayment product will you install, and does it cover the whole deck?
- Where will ice barrier or other self-adhered membrane go, which product, and how far up from the eave?
- Do any sections of my roof fall below 4:12, and how will you handle them?
Flashing
- For each wall, chimney, skylight, valley and pipe, is the flashing new or reused?
- For anything reused, who decides whether it is serviceable, when, and what is the unit price to replace a piece that is not?
- Is new drip edge included at both eaves and rakes? Is a kickout included where an eave meets a wall?
Ventilation and system
- What intake and exhaust will the finished roof have, and what happens to the existing vents?
- Which starter, hip and ridge, underlayment and ventilation products are you using, and which manufacturer warranty tier does that combination qualify for?
- Do you hold the credential that tier requires, who registers the warranty, and can you attach the warranty document?
Disposal, permits and terms
- Are disposal and dumpster in the price, including extra layers?
- Who pulls and pays for the permit, and is the inspection included?
- Are gutters removed and reset, replaced, or left alone?
Reading the two bids once they are comparable
After normalization, the remaining difference between two architectural-shingle bids usually sorts into a few honest categories.
The product category
Different shingle lines, even from one manufacturer, carry different weights, wind ratings and warranty terms. That is a real difference, and it belongs to the product documents, not to a guess about which brand is better.
The system category
A bid built to a manufacturer’s system tier, with matched accessories and a credentialed installer, is buying a different warranty document from a bid built to the standard shingle warranty. Both can be sound roofs. The difference should be visible on the bid, not inferred.
The scope category
New flashing against reused flashing, ridge venting against existing box vents, sheathing over spaced boards, disposal and permits. These are scope differences, not price differences, and each belongs on its own line.
The risk category
Unit prices for deck, layers and flashing decide how far the final invoice can move from the bid. A lower total with no unit prices is not necessarily the lower roof.
Route the normalized scope into the roofing tools
- Compare roof quotes takes two or three normalized bids and flags where they say different things.
- Roof quote analyzer steps one bid through a series of passes and writes the follow-up questions out.
- Roof estimate scope checker is a quick pass for the lines a bid is most likely to leave blank.
- Roof replacement cost explains the drivers behind a total once the bid defines the work.
- Roof replacement cost calculator works through those drivers for your roof without inventing a number for it.
- Roof repair vs replace observation tool is where to start if replacement is not yet settled.
- The roofing warranty guide explains manufacturer and workmanship coverage, and the Roofing hub has everything else.
What this page deliberately does not do
It does not publish a national price per square or per square foot for architectural-shingle roofs, and it does not repeat prices homeowners have posted in forums as if they were market facts. Roof size and pitch, removal scope, deck condition, flashing work, ventilation changes, the shingle line, the warranty tier and local labor move a shingle total enough that an averaged headline figure misleads more than it informs. The number that matters is the written bid for your house, once it specifies the work.
It does not treat any manufacturer’s system requirement as a code requirement, or any code section as universal: manufacturer conditions apply to that manufacturer’s warranty, and code provisions apply where your jurisdiction has adopted them. It does not rank shingle brands, lines or contractors, and it does not cover insurance or storm-damage claims, which follow different rules.
Common questions
Both bids name the same shingle. Why are they so far apart?
Because the shingle is one layer. The usual sources of the gap are removal scope, the deck assumption and its unit price, which flashings are new, ventilation changes, accessories and the warranty tier the roof is built to, plus disposal and permit. Read both bids into the matrix and the gap usually shows up as specific lines.
Is reusing flashing a red flag?
Not automatically. Some flashing, such as counterflashing set into a chimney, is commonly left in place on a reroof. The code position where the IRC is adopted is that flashings that are rusted, damaged or deteriorated must be replaced. What matters is that the bid says what is reused, who judges its condition, and what a replacement piece costs.
Is ice and water barrier required on every shingle roof?
No single answer covers the country. Under the IRC, an ice barrier is required in areas the jurisdiction designates as having a history of ice damming, and manufacturer system tiers may call for leak barrier products in other places. Ask the contractor which applies to your house and where the membrane will go. When two bids describe that membrane differently, the ice and water shield roof quote decoder breaks the line down location by location.
Does a matched-brand system make a better roof?
It changes which warranty document you can get. Manufacturers such as GAF, Owens Corning and CertainTeed tie their enhanced tiers to their own accessories and, at higher tiers, to credentialed installers. Whether that coverage is worth any price difference is your decision; the bid should make the tier and its conditions visible either way.
Can a shingle bid go over my existing roof?
Sometimes. Where the 2021 IRC applies, a recover is not allowed over a roof that already has two or more layers, a water-soaked or badly deteriorated roof, or certain coverings such as slate or tile, and some manufacturer tiers require removal to the deck. An overlay bid and a tear-off bid are different projects and should not be compared on total.
About the author
Chris Horton writes UpgradeWorth’s homeowner decision guides. He covers how replacement projects are scoped, quoted and warrantied, with a bias toward what a homeowner can verify in writing rather than what a salesperson says at the kitchen table. UpgradeWorth does not sell leads, rank contractors or accept placement fees.
Next: comparing a shingle bid with a metal bid instead? Use the asphalt vs metal roof quote decoder. Considering standing seam as an alternative? The standing seam roof quote decoder covers those bids. Only one bid so far? Start with the roof replacement quote checklist. Everything else is at the Roofing hub.