Roofing Quotes: Underlayment, Ice Barriers, and Drip Edge

Two roof-replacement quotes specify the same shingle brand, color, and advertised warranty. One costs less.

The lower quote says install code-compliant underlayment and metal edges. The other names the underlayment product and standard, self-adhering membrane locations, calculated eave coverage past the exterior wall line, valley and penetration details, low-slope treatment, drip-edge profile and metal, layer sequence, fasteners, deck assumptions, weather limits, inspection photographs, and warranty documents.

Those quotes do not describe the same roof simply because the visible shingles match.

Underlayment, self-adhering ice-barrier membrane, and drip edge sit beneath or beside the finished roof covering. The customer may never see them again. That makes them easy to hide in a vague allowance—and a useful way to tell whether two quotes actually cover the same roof.

A useful roofing quote states the proposed assembly by roof area. It does not rely on felt, synthetic, ice and water, or edge metal as complete specifications.

In Documentorium, use the site assessment checklist to name each roof plane, slope, eave, rake, valley, penetration, visible deck condition, and unverified area. Then put the chosen products, governing standards or manufacturer details, quantities, base scope, alternates, allowances, and exclusions in the roofing proposal and scope attachment. The five-line quote summary keeps the assembly choice visible near the price; the hidden-condition guide helps word the deck-repair stop point.

Quote a roof assembly, not a shingle package

For an asphalt-shingle replacement, the scope decisions that affect the finished assembly can include:

• roof framing and deck;
• deck joints, damaged sheathing, fasteners, and surface preparation;
• field underlayment;
• self-adhering or other approved ice-barrier/eaves protection;
• valleys;
• eave and rake drip edge;
• starter course and field shingles;
• sidewall, headwall, chimney, skylight, vent, pipe, and other flashing;
• ridges, hips, transitions, and penetrations;
• gutters and roof-edge interfaces;
• ventilation and moisture-control components; and
• sealants, compatible accessories, and fastening.

The 2024 model International Residential Code's roof-covering provisions illustrate the system approach. They list accepted underlayment standards by roof-covering type and wind condition, specify application and fastening tables, call for ice barriers in locally designated ice-dam areas, and require manufacturer installation instructions. The adopted code, amendments, approved product information, and project conditions govern the actual job.

Do not write meets IRC without identifying the jurisdiction and adopted edition. The model code does not tell you which edition or amendments the local authority enforces.

Map every roof area before selecting material

One building may contain:

• a main roof at 6:12;
• a porch at 3:12;
• a nearly flat cricket;
• a garage added under a different code cycle;
• a heated eave above an exterior wall;
• an unconditioned canopy;
• a valley receiving two planes;
• a lower roof receiving upper-roof runoff;
• a dormer with short eaves and sidewalls; and
• a membrane roof that should not receive shingles.

Give each plane and detail a stable ID:

• R-01 Main West;
• R-02 Main East;
• R-03 Porch Low Slope;
• V-01 North Valley;
• E-01 Heated Eave;
• RK-01 West Rake;
• P-01 Plumbing Vent; and
• SK-01 Existing Skylight.

For each area, record:

• measured roof area and slope;
• roof covering to remove and proposed replacement;
• deck type and visible condition;
• eave length, overhang, exterior-wall location, and heated-space relationship;
• rake length;
• valleys, walls, penetrations, transitions, and concentrated drainage;
• ice-dam history reported or observed;
• wind, snow, fire, wildfire, coastal, and corrosion conditions relevant to the assembly;
• attic, cathedral ceiling, spray foam, insulation, ventilation, and vapor-control configuration within the authorized assessment;
• manufacturer/system requirements;
• permit and adopted-code status; and
• inaccessible or concealed conditions.

Use a site assessment checklist and an annotated roof plan. Install ice and water at eaves is not measurable until the eaves and interior wall line are shown.

Roof-area IDs are documentation, not permission to reach every surface. OSHA's current residential fall-protection guidance explains that employers remain responsible for applicable fall-protection requirements and for selecting controls that fit the actual work. Record an inaccessible or unsafe area as such, then price a safer access method or a return visit instead of promising a roof walk in the sales scope.

Underlayment types are not interchangeable labels

ARMA's current steep-slope underlayment bulletin distinguishes asphalt-saturated organic felt, synthetic underlayment, and self-adhering polymer-modified bituminous underlayment. It points contractors back to local code and the shingle manufacturer's requirements for selection and installation.

That is the right estimating habit. Record enough detail to identify the actual product and installation basis:

Avoid brand-free language when brand or classification affects price and warranty. Avoid or equal without defining who decides equality, by which criteria, and before what approval gate.

Asphalt felt and synthetic underlayment need real specifications

15-pound felt is an old shorthand, not a complete current specification. ARMA explains that ASTM D226 covers two nonperforated steep-slope types commonly associated with traditional No. 15 and No. 30 language, while ASTM D4869 covers four types of asphalt-saturated organic felt intended for steep-slope underlayment.

The model IRC also recognizes multiple product standards and different permitted types by roof covering and wind condition. Synthetic products may use a specific ASTM standard, code evaluation, listing, or manufacturer/system basis. The word synthetic alone does not establish:

• tensile or tear performance;
• tested water-shedding performance;
• UV exposure period;
• slip resistance;
• cap-fastener requirements;
• temperature range;
• compatibility;
• vapor properties;
• fire-classification effect; or
• suitability under the proposed roof covering.

Write:

Install [manufacturer/product] underlayment, identified as complying with [applicable current standard/type/listing], over Roof Areas R-01 and R-02. Apply to prepared deck with the listed side/end laps and cap-fastener pattern for the project's wind conditions according to adopted requirements and current manufacturer instructions. Cover within the shorter of the product exposure limit, roof-covering requirement, or project weather-protection plan.

That lets the customer compare the actual concealed layer.

ASTM D1970 has a specific scope

As of August 14, 2026, ASTM lists ASTM D1970/D1970M-25 as the active edition. ASTM describes it as a specification for self-adhering polymer-modified bituminous sheet materials used as steep-roofing underlayment for ice-dam protection at eaves, valleys, or both.

The standard is important, but a reference to it does not answer every project question.

It does not, by itself, define:

• the exact product or thickness;
• required coverage on this building;
• whether the local code requires an ice barrier;
• compatibility with the selected shingle, metal, tile, primer, deck, or sealant;
• use at walls, penetrations, skylights, or full-roof coverage;
• application temperature and surface condition;
• lap dimensions and sequencing for the selected product;
• fire-classification or assembly effect;
• ventilation and moisture design;
• warranty coverage; or
• whether a similarly marketed peel-and-stick product actually complies.

Verify the package label, product data, current instructions, and approved use. Do not assume every roll marketed as ice and water shield is an ASTM D1970 product, and do not use a trademarked product name as a generic technical specification.

Calculate eave protection from the wall line

The model code's ice-barrier distance is not simply one 36-inch roll at every eave.

Section R905.1.2 of the 2024 IRC model roof provisions applies in areas designated as having a history of eave ice that backs up water. For the listed roof coverings, it requires protection from the lowest roof edge to at least 24 inches inside the exterior wall line. On roofs at 8:12 or steeper, it also sets a minimum of 36 inches measured along the roof slope from the eave edge. The model provision excepts detached accessory structures without conditioned floor area; local adoption and amendments control every project.

The estimator needs:

• distance from roof edge to exterior-wall line;
• roof slope;
• required inside-wall extension;
• membrane roll width;
• manufacturer-required laps;
• starter strip or drip-edge detail;
• obstructions and transitions;
• eave returns and dormers; and
• waste and repair allowance.

For an example calculation only:

In this example, the horizontal distance is 24 + 24 = 48 in; applying the 8:12 slope gives about 58 in along the roof. The point is not to reuse that result on another roof. It is to calculate the actual geometry. A wide overhang or steep slope can require more than one course even when the code language sounds like 24 inches inside.

Show the coverage on the roof plan and price courses, laps, and waste. If the authority or manufacturer requires protection beyond the model minimum, identify that governing detail.

Ice-barrier membrane does not prevent ice dams

It is secondary protection against water backup. It does not eliminate the mechanism that forms ice at the eave.

ARMA's ice-dam bulletin describes repeated thawing and freezing and frozen slush in gutters, and points to insulation, attic ventilation, eave/gutter conditions, and an ice-dam protection layer.

A roof quote should not promise ice-dam proof because self-adhering membrane is included. Separate:

• code-required or specified ice-barrier installation;
• attic air-leakage assessment or correction;
• insulation work;
• ventilation design and correction;
• gutter/downspout cleaning or replacement;
• snow/ice management; and
• interior damage repair.

Example boundary:

Price includes the listed self-adhering ice-barrier membrane at E-01 through E-04. This is a concealed secondary water-backup layer; it does not prevent ice-dam formation. Air sealing, insulation, ventilation redesign, gutter correction, snow removal, and interior remediation are excluded unless separately listed.

Do not use that exclusion to ignore a roof-system or code requirement the contractor owns.

Decide whether valleys and penetrations are included

Valleys concentrate water. Walls and penetrations interrupt the shingle field. Many contractors extend self-adhering membrane to these areas, but the quote should not rely on an unwritten shop habit.

Create a detail schedule:

Do not let ice and water in valleys substitute for the valley flashing and shingle method. The concealed membrane, exposed metal, shingle cut, fastener-free zones, laps, and upper/lower transitions need one compatible detail.

Full-deck self-adhering coverage changes the assembly

Some projects specify self-adhering membrane over the entire deck for wind, water, roof-covering, insurer, or local reasons. That is not merely an upgrade in roll count.

Verify:

• adopted code and approved assembly;
• roof-covering manufacturer acceptance;
• deck type, cleanliness, primer, temperature, and moisture;
• vapor permeance and drying path;
• attic or unvented-roof design;
• insulation and vapor-control layers;
• fire classification;
• future removal and reroof implications;
• fastener sealing claims and limitations;
• temporary exposure; and
• warranty.

ARMA's May 2025 underlayment bulletin explains that full-deck self-adhering underlayment acts as a vapor retarder and makes ventilation increasingly important. On an unvented assembly, that same vapor restriction still has to be addressed in the approved design. A quote cannot settle moisture control by writing full ice and water for extra protection.

If a designer has specified the assembly, identify the approved document. If no one has evaluated the moisture path, make that a preconstruction decision rather than a field upgrade.

Low-slope shingle areas need separate pricing

A porch at 3:12 should not disappear inside the same underlayment line as a 7:12 main roof.

ARMA's current lower-slope shingle bulletin addresses asphalt-shingle roofs from 2:12 up to, but not including, 4:12 and says shingles should not be applied below 2:12. It describes either a double-layer underlayment method or a single self-adhering layer; the adopted code, manufacturer instructions, ventilation, and project conditions still control.

For each lower-slope plane, quote:

• verified slope and measurement method;
• approved roof covering for that slope;
• underlayment or membrane system;
• course, lap, and transition detail;
• transition extension onto steeper roof where required;
• wall, valley, and drainage details;
• ventilation/moisture design;
• manufacturer warranty eligibility; and
• alternate membrane roof when shingles are not suitable.

Do not sell a shingle color before confirming that shingles are permitted on the plane.

Drip edge is a specified component, not miscellaneous metal

Drip edge helps direct water away from the roof deck and fascia and provides a finished line. The quote should identify:

• eave and rake lengths by ID;
• profile and dimensions;
• corrosion-resistant material;
• thickness/gauge or product specification;
• finish and color;
• kick or lower-edge geometry;
• deck and fascia extensions;
• segment length and laps;
• corners and transitions;
• fastening and spacing;
• relationship to starter/shingle overhang;
• relationship to underlayment or self-adhering membrane;
• gutter apron or gutter interface; and
• existing edge removal and fascia repair.

Section R905.2.8.5 of the 2024 model IRC calls for drip edge at eaves and rakes, gives minimum extensions, overlap, and fastening, and places underlayment over the drip edge at eaves and under it at rakes. The adopted local provision controls.

ARMA's current drip-edge bulletin describes the same general sequencing and also notes that some manufacturers or local codes permit a different eave detail with self-adhering underlayment, including a membrane/drip-edge layering detail. That is why the quote should cite the selected approved detail instead of saying standard install.

Example:

Install prefinished corrosion-resistant drip edge, Product DE-4, at E-01 through E-04 and RK-01 through RK-04. Use dimensions, laps, fasteners, spacing, corners, and shingle projection shown in Detail A-3. Sequence ordinary underlayment and eave ice-barrier membrane as shown in Detail A-4, consistent with the adopted code and current roof-system instructions. No substitution or reversed sequence without documented approval.

If the same scope includes new gutters, carry the edge IDs and approved layering into the gutter installation quote workflow. The gutter, apron, fascia, drip edge, membrane, starter course, and discharge path should not be sold as unrelated details by two crews.

The eave and rake sequence is not cosmetic

Water should lap from upper components onto lower components in the intended drainage direction. On a typical shingle roof:

• eave drip edge commonly goes beneath the field underlayment so water sheds onto it; and
• rake drip edge commonly goes over the underlayment so wind-driven water is directed onto the roof surface.

Self-adhering eave details can add a starter strip or sandwich sequence. Existing gutters, gutter apron, fascia wrap, starter course, low-slope transitions, and local high-wind details may change the approved assembly.

The estimator should include a section detail. The crew should not choose the sequence after tear-off based on whichever material was unloaded first.

Photograph:

1. Prepared deck at eave and rake.
2. First membrane/underlayment layer where required.
3. Drip edge profile, lap, fastening, and corners.
4. Overlying underlayment or membrane sequence.
5. Starter course and shingle projection.
6. Gutter/fascia interface.

Once shingles are installed, a customer cannot verify most of that sequence from the yard.

Existing self-adhering membrane creates a reroof decision

During tear-off, self-adhering membrane may be bonded tightly to the deck. Removing it can damage sheathing. Leaving it can create ridges, incompatible layers, trapped moisture concerns, fire-classification questions, or manufacturer restrictions.

Section R908.3 of the 2024 model IRC roof-replacement provisions includes limited paths for leaving certain adhered ice-barrier or self-adhered underlayment in place. Those paths depend on deck condition and, in some cases, manufacturer permission, the new covering layer, and limits on material buildup. They are model-code options, not blanket approval for every existing membrane; verify the adopted code and the selected roof system.

Write a differing-condition process:

Base price assumes existing underlayment can be removed without replacing sound deck except for the listed decking allowance. If bonded self-adhering membrane remains, the contractor will evaluate flatness, moisture or damage, roof-system acceptance, adopted reroof requirements, and new-product compatibility. The contractor will not conceal a wrinkled membrane or a wet, damaged, or unapproved condition and will document and obtain approval for deck replacement, an overlay detail, or another required correction before proceeding.

Price deck work with:

• included quantity, if any;
• unit price per sheet or square foot for a defined material/thickness and operations;
• rafter/truss/framing exclusion or separate process;
• edge blocking and clip treatment;
• permit/design trigger;
• interior protection;
• insulation/ceiling damage boundary;
• disposal; and
• schedule impact.

Decking extra without those fields turns a foreseeable reroof condition into a blank check.

Underlayment is not an unlimited temporary roof

Product exposure ratings are not promises that a partially completed building will remain dry through any weather.

The quote and work plan should distinguish:

• product's maximum published exposure under stated conditions;
• contractor's planned time before covering;
• temporary dry-in purpose and limitations;
• fastener holes, laps, penetrations, terminations, and edges;
• wind and rain forecast controls;
• daily tie-in and emergency protection;
• interior/customer-property protection;
• water-entry notification and response; and
• replacement criteria after prolonged exposure, contamination, damage, or loss of adhesion.

Do not advertise six-month exposure as a six-month water warranty without reading the current product instructions and warranty. Schedule roof covering as soon as the assembly and conditions permit.

Calculate material quantities from the details

Roof area alone does not determine concealed-layer quantities or cost.

Estimate:

Keep a calculation sheet in the estimate file. If a 28-square roof requires more than 28 squares of purchased underlayment because of roll coverage, laps, cuts, and detail work, explain the material basis rather than presenting unexplained waste.

Let customers compare two quotes by assembly

Use a comparison schedule:

The goal is not to make the longer quote win automatically. It is to reveal when the prices include different assemblies.

Separate base scope, alternates, and pending decisions

A clear proposal can include:

Base scope

• tear-off and disposal;
• deck preparation and included replacement allowance;
• specified field underlayment by area;
• required self-adhering membrane by eave/detail;
• specified drip edge at eaves/rakes;
• valleys, flashing, starter, shingles, ridge, ventilation, and accessories;
• permit/inspection responsibility;
• protection and weather plan;
• concealed-work photos; and
• cleanup, closeout, warranty delivery, and sign-off.

Alternates

• higher-performance or different approved underlayment;
• expanded self-adhering coverage after moisture/design review;
• upgraded drip-edge metal/profile/finish;
• open metal valleys instead of an approved closed system;
• roof-to-wall or skylight replacement detail;
• ventilation or insulation correction; and
• deck replacement above the included quantity.

Pending decisions

• adopted-code confirmation;
• roof-covering slope eligibility;
• manufacturer approval of an existing deck/assembly;
• insurer, fortified/high-wind, HOA, historic, or lender requirements;
• product/color availability;
• hazardous-material testing; and
• concealed deck condition after tear-off.

Do not put a code-required component in an optional upgrade merely to lower the base price. Base scope should describe one coherent assembly that can be permitted and approved under the stated assumptions.

Write operational exclusions

If authority review or manufacturer instructions change the feasible assembly after quote acceptance, do not improvise. Document the governing requirement, affected areas, price/schedule effect, and approval in a change order, subject to contract and law.

Carry the hidden details into the work order

If the quote follows storm damage or an insurer inspection, keep the contractor's assembly decision separate from the claim decision. The storm-damage inspection guide shows how to carry roof-area IDs and evidence into the quote without promising coverage, while the insurance-inspection quote workflow shows how to reconcile a third-party estimate with the contractor's own assembly.

The accepted quote should generate a roofing work order containing:

• controlling contract/quote revision;
• roof plan and detail IDs;
• tear-off layers and disposal;
• deck inspection and unit-price approval gate;
• each underlayment product and roof area;
• each ice-barrier membrane location and calculated extent;
• valley, wall, penetration, low-slope, and transition details;
• drip-edge profile, color, sequence, laps, and fasteners;
• substrate preparation, primer, temperature, moisture, and exposure limits;
• wind-condition fastening requirements;
• daily dry-in and weather response;
• no-cover inspection/photo hold points;
• material labels/lot records required for warranty;
• safety and access references; and
• customer communication and change authority.

Do not ask the crew to infer membrane coverage from the roll count. Put the coverage on the roof plan.

Inspect before the shingles hide the work

Use an inspection report by plane and detail.

At closeout, issue the actual roofing warranty and completion sign-off with the same plane IDs, product names, concealed-work photographs, approved changes, and remaining exceptions.

Record:

• deck condition, replacement, fasteners, gaps, and preparation;
• surface dry/clean status where relevant;
• underlayment product label and condition;
• course direction, flatness, laps, offsets, and fastening;
• cap/fastener type and pattern;
• tears, holes, fishmouths, wrinkles, contamination, and repairs;
• ice-barrier membrane extent past wall line;
• adhesion, primer, roll-down, laps, and terminations per selected product;
• valleys, walls, penetrations, and transitions;
• drip-edge product, extensions, laps, corners, fasteners, and sequence;
• starter/shingle projection and edge relationship;
• weather exposure or damage before cover;
• approved deviations and change records; and
• final water-shedding path into gutters or off the edge.

Do not puncture, peel, flood, or destructively test installed material without an approved method. Visual documentation does not prove every bond or concealed condition, but it can show that the intended materials and sequence existed before cover.

Split warranties by responsible party

The customer may receive:

1. roof-covering manufacturer warranty;
2. accessory or underlayment manufacturer warranty;
3. enhanced system warranty requiring eligible components and certified installation;
4. drip-edge finish or metal product warranty;
5. contractor workmanship warranty; and
6. separate deck, ventilation, skylight, gutter, or other trade coverage.

For each, state:

• company issuing the warranty;
• covered product/work;
• start and duration under actual terms;
• registration and documentation;
• approved installer/system eligibility;
• transfer rules;
• maintenance and notice;
• exclusions and remedies; and
• who assists with claims.

Do not call the entire assembly lifetime because a shingle wrapper uses that word. Do not promise leak-free performance from underlayment alone. A workmanship warranty should cover the contractor's listed installation while accurately separating excluded existing structure, unapproved alterations, maintenance, extreme events, condensation, and other noncovered causes—without attempting to waive nonwaivable rights.

Sources

Underlayment and self-adhering ice-barrier standards

• ASTM International — ASTM D1970/D1970M-25, Self-Adhering Polymer Modified Bituminous Sheet Materials Used as Steep Roofing Underlayment for Ice Dam Protection, active edition accessed August 14, 2026.
• ASTM International — D08.02 Steep Roofing Products and Assemblies, active standards list, accessed August 14, 2026.
• Asphalt Roofing Manufacturers Association — Steep Slope Roofing Underlayment, May 2025; accessed August 14, 2026.

Ice-dam protection and lower slopes

• Asphalt Roofing Manufacturers Association — Protecting Against Damage from Ice Dams, revised August 2024; accessed August 14, 2026.
• Asphalt Roofing Manufacturers Association — Installation of Asphalt Shingles on Lower Sloped Roofs, July 2025; accessed August 14, 2026.

Drip edge

• Asphalt Roofing Manufacturers Association — Installation of Drip Edge at Eaves and Rakes, May 2025; accessed August 14, 2026.

Model roof-assembly code context

• International Code Council — 2024 International Residential Code, Chapter 9: Roof Assemblies, Version 2.0, especially Sections R905.1.1, R905.1.2, R905.2.8.5, and R908.3; model-code context accessed August 14, 2026.

Construction access and fall protection

• Occupational Safety and Health Administration — Fall Protection in Residential Construction, guidance and applicable-standard context accessed August 14, 2026.

This article provides general educational information for U.S. roofing contractors and customers. It is not a roof design, code interpretation, product approval, installation instruction, engineering opinion, warranty determination, legal opinion, or safety plan. Follow the adopted code and amendments, approved construction documents, authority decisions, current manufacturer instructions, listed assembly, qualified design, and site-specific conditions.