Roofing materials on a quote: what each line should say

Every materials line on a roofing quote should name a product and a quantity, and only two of them have a public price. Shingles and decking can be set against the Census import chain as a floor: about $0.749 to $0.814 per kilogram of shingles (see is my roofing quote too high), and $13.03 to $14.16 per 4 by 8 foot sheet of 7/16 inch OSB, before freight and labor (Census IMDB, Census AIES 2024). Underlayment, ice barrier, drip edge, flashing and ridge vents have no clean public price, but the 2021 International Residential Code says where they go: a drip edge "shall be provided at eaves and rake edges of shingle roofs" (R905.2.8.5, as adopted by Seattle). Trusses and flat roof membranes are different again: one may need a registered design professional, and the other has no clean public price benchmark.

The materials lines, and what each can be checked against

The wording column is illustrative, written for teaching. A floor here means the import value of the material, plus an industry-average wholesale margin, plus a state transportation department's markup for materials on extra work.It leaves out freight to your street and every hour of labor, so an honest line sits above it. The floor is for spotting a line so far above it that freight, brand and labor do not explain it.

Code text on this page is quoted from the 2021 Seattle Residential Code. Seattle states it "has adopted the 2021 International Residential Code, with amendments specific to our jurisdiction" (City of Seattle); none of the sections quoted here carries a Washington or Seattle amendment mark. Your city may have adopted a different edition or amended it, so ask your building department.

Step 1: shingles, by squares, product line and weight

The shingle line should give three things. First, the squares: one square is 100 square feet of roof, and our guide on how many squares your roof is shows the pitch arithmetic. Second, the product line, because the code ties shingles to standards printed on the package. Asphalt shingles "shall comply with ASTM D3462", and their packaging "shall bear a label to indicate compliance with ASTM D7158" (or ASTM D3161 for shingles outside D7158's scope) for wind resistance (R905.2.4 and R905.2.4.1). Materials must arrive "in packages bearing the manufacturer's identifying marks" (R904.4). Third, the weight per square, which is on the manufacturer's product sheet.

With the weight you can compute a floor. Our roofing quote guide works it out in three parts. It starts from the Census import record for asphalt roofing and siding (HS 6807.90.0010, IMDB 2026-07). It adds the 28.35% wholesale margin for roofing distributors (Census AIES 2024) and state DOT markups of 15% to 25% that apply to materials on extra work. The result is $0.749 to $0.814 per kilogram, about $82 to $89 per square for the 240-pound square used there. For your product, multiply the pounds per square by 0.45359237 to get kilograms, then by $0.749 and by $0.814. These are import prices: shingles made in U.S. plants are not in this record, and the margin is an industry average, so treat the result as a reference point, not a hard minimum.

Expect the shingle line to be above that floor: freight, the brand you chose and any extra distributor tier sit on top. Ask about the line only when it is far above, and ask whether the squares include a waste allowance and how much.

Step 2: underlayment and ice barrier

Underlayment. Underlayment materials required to comply with "ASTM D226, D1970, D4869 and D6757" must "bear a label indicating compliance to the standard designation" (R905.1.1). So the line should name a product, and you can ask which standard is on its label. Slope matters too: for asphalt shingles on slopes from 2 in 12 up to 4 in 12, "double underlayment application is required" (R905.2.2). On a low-pitch roof, a quote showing one layer is worth a question.

Ice barrier. It is required only in some places. The code reads: "In areas where there has been a history of ice forming along the eaves causing a backup of water as designated in Table R301.2, an ice barrier shall be installed for asphalt shingles" (R905.1.2). Where required, it covers the roof "from the lowest edges of all roof surfaces to a point not less than 24 inches (610 mm) inside the exterior wall line of the building". On slopes of 8 in 12 or steeper it also runs "not less than 36 inches (914 mm) measured along the roof slope from the eave edge". Your building department can tell you whether your area is designated.

So the check runs both ways. In a designated area, an ice barrier line that is missing, or stops short of 24 inches inside the wall line, is a question. Outside one, R905.1.2 does not require it, so it is a choice and the quote should say why it is there. On a full replacement, an existing ice barrier adhered to the deck may stay if it is covered with a new one (R908.3, exception).

Step 3: drip edge, flashing and ridge vent

Drip edge. "A drip edge shall be provided at eaves and rake edges of shingle roofs." Segments overlap "not less than 2 inches". The drip edge extends "not less than 1/4 inch (6.4 mm) below the roof sheathing", and it is fastened "at not more than 12 inches (305 mm) o.c." (R905.2.8.5). The quantity is the length of your eaves plus your rakes, in linear feet. "Drip edge if needed" on a shingle roof should read "drip edge".

Flashing. Flashings go "at wall and roof intersections, wherever there is a change in roof slope or direction and around roof openings" (R903.2.1). Sidewall flashing is continuous or step flashing "not less than 4 inches (102 mm) in height and 4 inches (102 mm) in width" (R905.2.8.3). A chimney or penetration "more than 30 inches (762 mm) wide as measured perpendicular to the slope" gets a cricket or saddle on its ridge side (R903.2.2). On a reroof, "Flashings shall be reconstructed in accordance with approved manufacturer's installation instructions" (R908.6). The reroofing section also says existing "flashings, edgings, outlets, vents or similar devices that are a part of the assembly shall be replaced where rusted, damaged or deteriorated" (R908.5). A quote that says "reuse existing flashing" should say who decides what is reusable, and when.

Ridge vent. Enclosed attics "shall have cross ventilation" (R806.1), unless the attic is built as an unvented assembly under R806.5.The minimum net free ventilating area is 1/150 of the vented space. It drops to 1/300 where, among other conditions, 40% to 50% of it is in upper vents within 3 feet of the ridge and the rest is in the bottom third of the attic (R806.2). For a 1,500 square foot attic that is 1,500 / 150 = 10 square feet, or 1,500 / 300 = 5 square feet. Of the 5, 2.0 to 2.5 square feet would be upper vents. A ridge vent is one kind of upper vent. Ask for its net free area per foot from the product sheet, the linear feet, and where the lower, intake air comes in.

Step 4: decking, OSB or plywood, priced per sheet

Asphalt shingles "shall be fastened to solidly sheathed decks" (R905.2.1). Whatever panel the quote names, wood structural panels must be "identified for grade, bond classification and performance category by a grade mark or certificate of inspection issued by an approved agency" (R803.2.1). Their roof spans may not exceed Table R503.2.1.1(1) or APA E30 (R803.2.2). That table lists a minimum nominal thickness of 7/16 inch for a 24/16 span rating and 15/32 or 1/2 inch for 32/16 (Table R503.2.1.1(1)). So the decking line should name the panel, the thickness and a price per sheet.

The Census import record gives a floor per sheet. Census reports these panels in cubic meters, so the arithmetic converts a sheet to volume. We assume a 4 by 8 foot sheet; scale it if your quote names another size. 4 ft x 8 ft = 32 square feet = 2.97290 square meters (32 x 0.09290304). At 7/16 inch (0.0111125 m) that is 0.0330363 cubic meters; at 15/32 inch (0.01190625 m), 0.0353961 cubic meters. Formula: landed value per cubic meter, divided by (1 - 0.26352), times 1.15 to 1.25, times the sheet volume. The 0.26352 is the AIES 2024 wholesale margin of the industry the chain maps these panels to (NAICS 423310). The 1.15 to 1.25 are state DOT markups that apply to materials on extra work (Caltrans 15%, FDOT 17.5%, TxDOT 25%), set for extra work on public contracts, not private-market markups.

Source: Census IMDB 2026-07 and Census AIES 2024, computed by USCCDB (doi:10.5281/zenodo.22979157). Census does not label any line as roof sheathing; these are the two OSB lines and two of the softwood plywood lines described as rough or touch sanded (southern pine and Douglas fir faces); other plywood lines price higher. The figures are import prices: domestic mills' prices are not in this record, and freight to your street is not included. Example: OSB line 0010 is $252.5543 / 0.73648 = $342.92 at wholesale, $394.36 to $428.65 after markup, and x 0.0330363 = $13.03 to $14.16 per sheet.

The "as needed" wording. Nobody knows how much decking is rotten until the old roof is off, so "as needed" is honest wording. What makes it checkable is a price per sheet and a way to count. Illustrative quote, written for teaching: "Replace damaged decking as needed, 7/16 in. OSB, $85 per sheet installed." If 12 sheets are replaced, that is 12 x $85 = $1,020. The material floor is 12 x $13.03 = $156.36 to 12 x $14.16 = $169.92. So about $71 to $72 of each $85 sheet pays for removal, labor, nails, disposal, overhead and profit. That is not wrong in itself; it tells you what you are paying for. Ask for the per-sheet price in writing, a cap or an estimate of the count, and photos of the sheets replaced. A full redeck is a different line: 100 / 32 = 3.125 sheets per square before waste.

Step 5: trusses or rafters on a reroof quote

Framing lines turn up on a reroof quote for a few reasons: rot found once the deck is open, a sagging ridge, or a heavier new roof. The code's reroofing section covers loads: "The structural roof components shall be capable of supporting the roof covering system and the material and equipment loads that will be encountered during installation" (R908.2). Rafters "shall be sized based on the rafter spans in Tables R802.4.1(1) through R802.4.1(8)" (R802.4.1).

Trusses are where an engineer or a permit may come in. Wood trusses "shall be designed in accordance with accepted engineering practice" (R802.10.2). Truss design drawings "shall be provided to the building official and approved prior to installation" (R802.10.1). The drawings "shall be prepared by a registered design professional where required by the statutes of the jurisdiction" (R802.10.2). Repairs are tighter still: "Truss members shall not be cut, notched, drilled, spliced or otherwise altered in any way without the approval of a registered design professional" (R802.10.4).

No public price exists for rafter or truss repair, so the check is the scope. A line such as "sister 4 rafters, 2x6, 10 ft" can be compared between quotes; "structural repairs as needed" cannot. For trusses, ask who designed the repair, whether an engineer's letter or drawing comes with it, and whether a permit will be pulled. Whether your city requires a permit for the reroof itself is a question for your building department.

Flat and low-slope roofs: no clean public price for membranes

Shingles stop at a slope: "Asphalt shingles shall be used only on roof slopes of 2 units vertical in 12 units horizontal (17-percent slope) or greater" (R905.2.2). Below that, the code lists other coverings, including the membrane families quotes name as modified bitumen, EPDM and TPO. Modified bitumen roofing complies with the standards in Table R905.11.2 (R905.11.2). Thermoset single-ply roof coverings "shall comply with ASTM D4637 or ASTM D5019" (R905.12.2); ASTM D4637 is the specification for "EPDM Sheet Used in Single-Ply Roof Membrane" (ASTM). Thermoplastic single-ply roof coverings "shall comply with ASTM D4434, D6754 or D6878" (R905.13.2); ASTM D6878 covers "Thermoplastic Polyolefin-Based Sheet Roofing", that is TPO (ASTM).

Each family has a design slope of not less than 1/4 unit in 12 for drainage (R905.11.1, R905.12.1, R905.13.1). Reroofing need not meet that minimum "for roofs that provide positive roof drainage" (R908.1, exception 1).

The honest note: there is no clean public price benchmark for these membranes. USCCDB has no Census import line or state DOT bid item for TPO or EPDM roofing. The one Census line that includes modified bitumen is asphalt articles in rolls (HS 6807.10.0000), and it mixes modified bitumen with other rolled asphalt products. Its January to July 2026 landed value is $1.6901 per kilogram; $1.6901 / 0.716507 = $2.3588 at wholesale, and times 1.15 to 1.25 that is $2.71 to $2.95 per kilogram (Census IMDB 2026-07, Census AIES 2024, computed by USCCDB). Because the line mixes products, it is not a usable benchmark for one membrane (we looked, USCCDB). So the check is the specification. Ask for the membrane type and the ASTM standard it meets, and its thickness from the product data sheet. Ask how it is attached, what insulation board goes under it, the squares, and the edge metal. With those in writing, two flat roof quotes can be compared line for line even without a public price.

Warning signs in the wording, not the numbers

• "Decking as needed" with no price per sheet. The wording is fine; the missing unit price is not. Ask for the price per sheet, the thickness and photos of each sheet replaced.
• "Drip edge if needed" on a shingle roof. The code says a drip edge "shall be provided at eaves and rake edges of shingle roofs" (R905.2.8.5).
• "Reuse existing flashing." The code's reroofing section says existing flashings "shall be replaced where rusted, damaged or deteriorated" (R908.5). Ask who decides, and what the price becomes if they cannot be reused.
• "Lay the new shingles over the old." A roof recover is not permitted "Where the existing roof has two or more applications of any type of roof covering". Nor is it permitted where the existing roof is water soaked or deteriorated (R908.3.1.1). Ask how many layers are on the roof now.
• "Truss repair" with no drawing. Truss members may not be altered "without the approval of a registered design professional" (R802.10.4).
• "This price is only good today." If a seller sells you something for $25 or more at your home, the FTC Cooling-Off Rule usually applies. You may cancel "prior to midnight of the third business day". There are listed exceptions, such as a bona fide emergency where you waive the right in a signed statement in your own handwriting (16 CFR Part 429). See what to do when the price is only good today.

The FTC's advice is that a written estimate "should include a description of the work to be done, materials, completion date, and the price" (FTC). Materials named one line at a time is exactly that.

What to ask the contractor, in one message

1. Shingles: the squares, the product line, the weight per square, and the waste allowance included.
2. Underlayment and ice barrier: product names, the ASTM standard on each label, single or double layer, and how far the ice barrier runs. Is our area designated for ice barrier?
3. Drip edge, flashing and ridge vent: linear feet of each, new or reused flashing, and the ridge vent's net free area and intake vents.
4. Decking: OSB or plywood, thickness and span rating, price per sheet, an estimated count, and photos of sheets replaced.
5. Framing: which members, how they are repaired, who approved the repair, and whether a permit will be pulled.
6. Low-slope sections: membrane type and ASTM standard, thickness, attachment, insulation and squares.

If you would rather not do it line by line, upload the quote and we do it, with every source and formula printed beside every number. We are paid by homeowners only and take no fee from contractors. Check a quote from $39, or get a free teardown first.

Questions

How much should a sheet of roof decking cost on a quote?

Public data give a floor, not a fair price. From the Census import record for January to July 2026, a 4 by 8 foot sheet of 7/16 inch OSB works out to $13.03 to $14.16 on the lower-priced Census OSB line ($16.52 to $17.96 on the other), after an industry-average wholesale margin and state DOT markups of 15% to 25% that apply to materials on extra work. Freight, labor, removal, nails, overhead and profit sit on top, so an installed per-sheet price will be higher. Ask for the price per sheet in writing.

Do I need ice and water shield on my roof?

Only where your area is designated for it. The 2021 International Residential Code (as adopted, for example, by Seattle) requires an ice barrier for asphalt shingles in areas with a history of ice forming along the eaves causing a backup of water, as designated in Table R301.2, running to at least 24 inches inside the exterior wall line. Ask your building department whether your area is designated.

Is drip edge required on a new shingle roof?

Under the 2021 International Residential Code (as adopted, for example, by Seattle), yes: R905.2.8.5 says a drip edge shall be provided at eaves and rake edges of shingle roofs, overlapped at least 2 inches and fastened at not more than 12 inches on center. Check which edition your city adopted.

Why would a roofer need an engineer for trusses?

The 2021 International Residential Code (as adopted, for example, by Seattle) says wood trusses shall be designed in accordance with accepted engineering practice, and that truss members shall not be cut, notched, drilled, spliced or otherwise altered without the approval of a registered design professional, and truss design drawings go to the building official for approval before installation. Ask who approved any truss repair on your quote. Check which edition your city adopted.

Is there a public price for a flat roof membrane like TPO or EPDM?

Not a clean one. Census has a broad import line for asphalt articles in rolls (HS 6807.10), which includes modified bitumen roll roofing but mixes it with other rolled asphalt products. We found no Census line or state DOT bid item for TPO or EPDM roofing. Compare quotes by specification instead: membrane type and ASTM standard (D4637 for EPDM, D6878 for TPO), thickness, attachment, insulation and squares.

Sources

Every figure above links to the public record it comes from. Wages were looked up in USCCDB v1.0, which carries the BLS file as published. Agency pages, reports and rules are quoted as published on October 16, 2026; check the source for changes.

1. U.S. Census Bureau, U.S. imports for consumption, landed duty-paid value and quantity, HS 4410.12.0010, 4410.12.0020, 4412.39.4031, 4412.39.4011, 6807.90.0010 and 6807.10.0000, January to July 2026 (IMDB 2026-07)
2. U.S. Census Bureau, Annual Integrated Economic Survey 2024, wholesale trade basic data (gross margins, NAICS 423310 and 423330)
3. 2021 Seattle Residential Code, Chapter 9 Roof Assemblies (Sections R903, R904, R905, R908)
4. City of Seattle, Department of Construction and Inspections, Seattle Residential Code ("Seattle has adopted the 2021 International Residential Code, with amendments specific to our jurisdiction")
5. 2021 Seattle Residential Code, Chapter 8 Roof-Ceiling Construction (Sections R802.4.1, R802.10, R803.2, R806)
6. 2021 Seattle Residential Code, Chapter 5 Floors, Table R503.2.1.1(1) Allowable spans and loads for wood structural panels for roof and subfloor sheathing
7. Caltrans Local Assistance training, Module 8 Payment (January 6, 2026), citing Standard Specifications 9-1.04C (materials markup 15%)
8. Florida Department of Transportation, Standard Specifications FY 2026-27, 4-3.2.1(4)(a) (markup 17.5%)
9. Texas Department of Transportation, Standard Specifications 2024, Item 9, Article 9.7.1.3 (materials markup 25%)
10. United States Construction Cost Database (USCCDB) v1.0, doi:10.5281/zenodo.22979157, CC BY 4.0
11. ASTM International, D4637/D4637M-15(2021)e1, Standard Specification for EPDM Sheet Used in Single-Ply Roof Membrane
12. ASTM International, D6878/D6878M-26, Standard Specification for Thermoplastic Polyolefin-Based Sheet Roofing
13. Federal Trade Commission, Cooling-Off Rule, 16 CFR Part 429
14. Federal Trade Commission, consumer advice: How To Avoid a Home Improvement Scam

Related guides

• Is my roofing quote too high?
• How many squares is my roof?
• Teardown 01: $19,872 for a 24-square roof in Austin

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