Cost & Quoting

Cost Estimation and Quoting for Roofing, Siding, and Exterior Metal Products

A money-first breakdown of what actually lands in your cost per square, and the line items estimators routinely forget.

In roll-formed roofing and siding, material is 60 to 75 percent of cost per square, so your quote lives or dies on the metal number. Landed steel at 0.95 dollars per pound and 2.752 lb per linear foot on a 36 in coverage panel means metal alone is 2.61 dollars per foot, or 87 cents per sq ft (87 dollars per square) before trim. Add the trim burden of roughly 15 to 18 percent from the Scrap Trim Cost calculator and effective metal cost climbs to about 102 to 103 dollars per square. Quote the delivered coil price locked to a coil, not last month's index, because a 10 percent CRU swing moves a whole quote by 8 to 9 dollars per square.

Coating is the second material lever and it is easy to underprice. A 55 percent solids paint at 32 dollars per gallon covering 1,103 sq ft per gallon single-side costs 2.9 cents per sq ft per side; painted both sides doubles to 5.8 cents, or about 5.80 dollars per square. Premium PVDF systems at 70 to 90 dollars per gallon push coating to 14 to 18 dollars per square. Use the Coating Cost per Square calculator with your actual dry mils, because building 1.0 mil when the spec allows 0.8 mil quietly adds 25 percent to paint cost across every job.

Machine time is a rate, not an afterthought. If your line and crew cost 320 dollars per hour fully burdened and the Line Speed Capacity calculator shows 3.6 squares per minute effective, that is 216 squares per hour, so conversion cost is 320 / 216 equals 1.48 dollars per square. But that assumes availability; at 78 percent uptime the real rate is 1.90 dollars per square, and a line stuck at 60 percent uptime runs 2.47 dollars per square. Small run jobs get crushed by setup: a 45 minute changeover on a 40 square order adds 8.33 dollars per square in machine time alone.

Changeover and scrap are cost buckets, not rounding error. The Color Changeover Loss calculator turns purge feet into dollars; 14 changes at 90 feet each on a 26 dollar per square value is roughly 983 dollars a shift, which on 1,348 squares produced is 73 cents per square spread across everything. Short colorful runs carry far more. Estimators who apply a flat 3 percent scrap factor understate reality on a job with heavy changeover and understate it further on thin gauge, where the same trim inches are a larger share of a lighter coil.

Labor beyond the line includes packaging, staging, and installer kits. The Installer Kit Quantity and Packaging Length Optimization calculators drive real material: at 80 fasteners per square times a 30 dollar per thousand fastener cost, screws add 2.40 dollars per square, and closures, sealant tape, and end caps add another 3 to 6 dollars per square on a trim package. Pack labor at 0.35 to 0.60 dollars per square is small but real. Forgetting the kit is the classic reason a quote that looked profitable at the line loses money on the dock.

Overhead and freight ride on top. Plant overhead of 12 to 20 percent on cost, applied to a roughly 115 dollar per square subtotal, adds 14 to 23 dollars. Freight on metal is weight-driven: at 2.752 lb per foot and 3.0 sq ft per foot, a square weighs 92 lb, so a 48,000 lb truckload carries about 520 squares, and a 2.50 dollar per mile 600 mile lane (1,500 dollars) is 2.88 dollars per square. Long thin panels ship air; the Packaging Length Optimization calculator helps you cube out a trailer instead of weighing it out.

Warranty reserve is the line item most quotes skip entirely. A 40 year paint and substrate warranty carries real expected liability; the Warranty Reserve calculator converts a claim rate and average remediation cost into a per square accrual. If historical claims run 0.4 percent of squares sold at an average settlement of 900 dollars per claimed square, the accrual is 0.004 x 900 equals 3.60 dollars per square. Underfunding this by even 2 dollars per square on 200,000 squares a year is 400,000 dollars of unbooked liability that surfaces years later.

Assemble the quote as a stack and defend each layer: effective metal 102, coating 6, machine time 1.90, changeover and scrap 1.20, kit and packaging 5, overhead 18, freight 2.90, warranty reserve 3.60, totaling about 140 dollars per square cost, then apply margin. The most common quoting error is quoting on coverage squares while paying for entry-width metal, which understates material by the full trim fraction. Reconcile the quote against a mass balance from the Coil Yield by Profile figure so pounds paid equals pounds shipped plus scrap, and no cost hides in the gap.

Published 2026-07-01.