How to Evaluate a Roof Coating Proposal

What every proposal must include

A complete roof coating proposal is a detailed document that specifies every aspect of the project — not a one-page letter with a price at the bottom. The level of detail in the proposal reflects the level of thought the contractor has put into the project. A detailed proposal means the contractor has evaluated your roof, designed a system, and planned the execution. A vague proposal means they are selling a generic service without tailoring it to your roof's specific conditions.

At minimum, the proposal should include these elements. Survey summary (what they found during the roof evaluation). Coating system specification (manufacturer, product name, chemistry, number of coats, target DFT). Preparation scope (pressure washing, seam repairs with linear footage, flashing repairs, moisture remediation with square footage, priming). Material quantities (gallons of each product). Project timeline (start date, duration, weather contingency). Cost breakdown (preparation, materials, labor, equipment). Warranty terms (manufacturer and contractor). Quality verification procedures (thickness testing, documentation deliverables).

If any of these elements are missing, ask the contractor to include them before you compare proposals. You cannot meaningfully compare a detailed proposal against a vague one. The detailed proposal will always appear more expensive because it specifies everything that the vague one leaves out — and the vague one's unspecified items will appear as change orders during the project.

Evaluating the scope of work

The scope of work should describe every task the contractor will perform, in sequence, from mobilization to demobilization. Read the scope as a narrative of what will happen on your roof, day by day. If you cannot visualize the project from the scope description, it is too vague. A scope that says "clean, prime, and coat roof" tells you almost nothing. A scope that says "pressure wash at 3,000 PSI, repair 120 linear feet of open seams with reinforcing fabric, prime with XYZ EPDM primer at 1 gallon per 200 square feet, apply two coats of ABC silicone at 1.5 gallons per 100 square feet per coat" tells you exactly what you are buying.

The scope should address what happens when unexpected conditions are found during the project. Despite the best survey, additional issues may be discovered once preparation begins — additional wet insulation, deck damage not visible from above, or membrane conditions worse than the surface indicated. The proposal should state how these discoveries will be handled: a pre-approved change order process with unit prices for common additions (insulation replacement at $X per square foot, additional seam repair at $X per linear foot).

Compare scopes across proposals by creating a checklist of items and checking whether each proposal includes them. If Contractor A includes moisture remediation for 2,000 square feet and Contractor B does not mention moisture remediation, the proposals are not comparable. Either Contractor A is pricing more work (explaining a higher total) or Contractor B is ignoring a condition that will surface as a change order.

Evaluating the coating specification

The proposal should name the specific coating product — manufacturer and product line — not just "silicone coating." Different silicone products from different manufacturers have different performance characteristics, solids content, application rates, and warranty terms. Knowing the specific product allows you to verify the application rate, check the manufacturer's warranty terms independently, and compare across proposals.

The target dry film thickness should be stated explicitly. A proposal that specifies "two coats of silicone" without a DFT target gives the contractor latitude to apply thinner-than-optimal coats. The DFT target — typically 20 to 25 mils for silicone, 15 to 20 mils for acrylic — is what determines coating lifespan. Without this number, you have no basis for quality verification after the project.

Verify that the material quantity matches the application rate for the specified product. If the product data sheet specifies 1.5 gallons per 100 square feet per coat, and the roof is 20,000 square feet, two coats require 600 gallons. If the proposal lists 450 gallons, the math does not work — the contractor is either planning to apply thinner than specified or has made an error. Either way, the discrepancy should be resolved before you sign.

Evaluating the preparation scope

Preparation items should be quantified in the proposal — not described with vague phrases like "repair as needed." Seam repair should specify linear footage. Moisture remediation should specify square footage. Flashing repairs should identify which flashings. Pressure washing should confirm the entire roof area. Each quantified item allows you to verify that the work was completed and compare preparation scope across proposals.

The preparation scope should correlate with the survey findings. If the survey identified 8% wet insulation on a 20,000-square-foot roof, the preparation scope should include 1,600 square feet of insulation replacement. If the proposal does not include insulation replacement despite the survey showing wet areas, the contractor is either ignoring the survey findings or plans to coat over wet insulation. Neither is acceptable.

Ask the contractor to explain any discrepancy between the survey findings and the preparation scope. There may be a legitimate reason — perhaps they believe the moisture readings were borderline and the insulation can be monitored rather than replaced. But you deserve to understand the rationale and make an informed decision about whether to accept that risk.

Comparing warranty terms across proposals

Warranty comparison requires reading the actual warranty documents — not the summary in the proposal. A proposal may say "15-year warranty" while the warranty document reveals it is a material-only warranty that excludes labor costs for re-application, excludes consequential water damage, and requires annual inspections by the original contractor to remain valid. The number of years is meaningless without understanding what those years cover.

Compare these specific warranty terms across proposals. Coverage period. What is covered (material defects, adhesion failure, UV degradation, ponding resistance). What is excluded (storm damage, foot traffic, improper maintenance, pre-existing conditions). Whether the warranty is prorated (full coverage for X years, then declining coverage). Whether the warranty is transferable to a new building owner. What the claim process requires (written notice period, inspection requirements, remedy options).

A 10-year full warranty with clear terms is more valuable than a 20-year prorated warranty with extensive exclusions. A prorated 20-year warranty that covers only 50% of material cost at year 10 and 25% at year 15 provides significantly less protection than a full 10-year warranty covering 100% of material and labor. Read the terms. Compare the real coverage. Do not compare headline years.

Comparing price: why lowest is not always best

The lowest-priced proposal often reflects the smallest scope of work, not the most efficient contractor. A $62,000 proposal that omits moisture remediation, uses one coat instead of two, skips priming, and provides a 7-year warranty is not comparable to a $78,000 proposal that includes all preparation, two full coats at specification, and a 12-year warranty. The first delivers less coating, less preparation, and less protection.

Calculate the cost per year of warranted service for each proposal. A $78,000 proposal with a 12-year warranty costs $6,500 per year. A $62,000 proposal with a 7-year warranty costs $8,857 per year. The "more expensive" proposal is actually 27% cheaper per year of warranted protection. This comparison normalizes the differences in scope and warranty period.

Also compare the cost per year of expected service (not just warranted service). A well-specified silicone system may realistically last 12 to 15 years. A minimally specified system may realistically last 7 to 10 years. Using the realistic lifespan (midpoint of the range) provides a more accurate cost-per-year comparison than the warranty period alone.

Proposal red flags

A single-line proposal with no itemized breakdown is the most common red flag. "Coat 20,000 square foot roof — $65,000" tells you nothing about what you are buying. What chemistry? How many coats? What DFT? What preparation? What warranty? This proposal cannot be compared against others, cannot be verified during the project, and cannot be enforced if the work is deficient.

A proposal that does not reference a pre-project survey means the contractor is specifying a system without knowing the roof's actual condition. Their material quantities, preparation scope, and pricing are based on assumptions. If those assumptions are wrong — and they often are — the project will face change orders, scope additions, and cost overruns that the "low" bid did not anticipate.

A proposal with a warranty period significantly longer than the industry norm for that chemistry should be questioned. A 20-year warranty on an acrylic coating (which has a 7 to 12 year expected lifespan) means either the warranty is heavily prorated, extensively excluded, or the contractor is making promises they cannot keep. Match the warranty period to the coating chemistry's realistic performance range — 10 to 15 years for silicone, 7 to 12 for acrylic, 15 to 30 for SPF.

A proposal that requires more than 50% upfront payment before work begins is unusual for commercial roofing. Standard payment terms for commercial coating projects are 10% to 30% at contract signing (covering material procurement), 40% to 60% at project midpoint (after preparation and first coat), and the balance upon completion and verification. Contractors who require full payment before starting have your money and reduced incentive to resolve deficiencies.

Questions to ask before signing

"Can I see the moisture survey report that informed this proposal?" If the answer is no — either because no survey was done or the contractor will not share the results — you do not have enough information to evaluate the preparation scope or the overall project recommendation.

"What is the total material quantity for this project, and how does it match the manufacturer's specified application rate?" Do the math yourself. If the numbers do not add up, ask the contractor to explain the discrepancy.

"What documentation will I receive at project completion?" The answer should include thickness readings, material usage records, photos, and warranty certificates. If the answer is vague or the contractor seems surprised by the question, their quality verification process may be informal or nonexistent.

"What is your change order process if additional work is needed during the project?" The answer should describe a documented approval process — the contractor identifies the issue, provides a written cost estimate, and obtains your written approval before performing additional work. A verbal "we will handle it and adjust the final bill" process creates disputes.

How to compare three proposals side by side

Create a comparison matrix with the following line items for each proposal. Coating manufacturer and product. Number of coats and target DFT. Total material quantity. Preparation scope (pressure washing, seam repair footage, insulation replacement footage, priming). Timeline. Manufacturer warranty period and type. Contractor warranty period. Quality verification procedures. Total price. Payment terms. Cost per year of warranted service.

The comparison matrix will immediately reveal which proposals are complete and which are missing elements. Proposals with gaps need to be returned to the contractor for supplemental information before they can be fairly compared. Once all three proposals have equivalent detail levels, the comparison becomes straightforward — you can see where the differences are and what drives the price variation.

Choose the proposal that delivers the best combination of scope, quality, and cost per year of warranted service — not the lowest total price. A well-specified proposal from a quality-focused contractor, at a fair price, is the foundation of a coating project that performs for its full expected lifespan. Call (251) 250-2255 to request a detailed proposal for your commercial roof.