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Starter shingles and ridge cap are two of the smaller line items on a roofing estimate, yet they generate a disproportionate share of questions once two estimates are compared side by side. Both are calculated differently from field shingles, and knowing how helps explain why the numbers sometimes look mismatched at first glance.
Starter shingles are the first course installed along the eaves and, on many roofs, the rakes, providing an adhesive strip and a solid base that seals the tab cutouts of the first course of field shingles above them and resists wind uplift at the roof’s most vulnerable edges. Starter is measured in linear feet, calculated from the total length of eaves, and often rakes as well, depending on the shingle manufacturer’s installation instructions and the specific product used. Because starter strip is purchased in bundles covering a fixed linear footage per bundle, and because roofs rarely have eave lengths that divide evenly into that figure, some waste is built into the calculation, though it is generally modest compared to field shingle waste since starter runs in a relatively straight line along most eaves.
Ridge cap, sometimes called hip and ridge, is also measured in linear feet, calculated from the combined length of all ridge and hip lines on the roof. Some roofing systems use cut-up three-tab shingles as ridge cap, while others specify a manufacturer’s purpose-built hip and ridge product designed for improved wind resistance and often required to maintain certain wind warranties. The choice between these two approaches affects both the unit cost and the coverage rate per bundle, since purpose-built ridge products typically cover less linear footage per bundle than shingles cut into thirds for the same purpose, which changes the quantity of bundles the calculation calls for.
Both starter and ridge cap quantities are typically derived directly from the roof sketch in estimating software, which calculates total eave length, rake length, hip length, and ridge length from the measurements entered or captured during inspection. A discrepancy between two estimates on these line items often traces back to a difference in the underlying sketch measurements themselves, rather than a disagreement about waste factor or pricing philosophy, which makes comparing the two sketches, not just the two estimate totals, a useful first step when starter or ridge figures do not match. Field verification of these lengths is generally straightforward compared to some other roofing measurements, since eave, rake, hip, and ridge lengths can be checked with a tape measure or confirmed against aerial and satellite measurement reports that many estimators use alongside or instead of a manual sketch, and when a sketch-derived measurement and a ground-level tape measurement disagree by more than a small margin, that gap is usually worth resolving before comparing the pricing built on top of it.
Because starter and ridge cap play a direct role in a roofing system’s wind resistance, some manufacturers’ installation instructions and some local building codes specify minimum requirements for their use, and an estimate that omits appropriate starter or ridge cap for the shingle system being installed may not reflect a code-compliant or manufacturer-compliant repair. Whether a given estimate correctly accounts for these requirements is a technical, verifiable question, answered by reviewing the applicable manufacturer specifications and any adopted local code provisions for the jurisdiction where the structure sits.
This article is general education about how the appraisal process commonly works. It is not legal advice, and specific procedures can vary by state and policy.
Russ Lis is a working property insurance appraiser and umpire based in Minnesota, serving clients nationwide. Contact Appraisal Resolution.