Our calculators publish a band. This section takes public pricing records — building permits, state audit reports, public bid tabulations — and asks a narrower question than you might expect: can this record check our band at all? Often it cannot, and the reason it cannot is the useful part.
Permit data
Los Angeles issued 7,477 re-roof permits in the first seven months of 2026, each carrying a dollar figure. Most land on exactly two per-square rates from a table. A minority use a different description form and look self-reported — and even those cannot check our band.
Comparison rejected — most filings carry a schedule rate, and the minority that look self-reported cannot be separated from an incentive to file low
Public bids
A Texas school district opened four sealed roofing proposals for the same building on the same morning in 2019. The highest was 2.39 times the lowest — and the document cannot tell you the roof's size, who won, or what was finally paid.
N/A — not a band check
Roofing
A state audit published a median re-roof cost for Louisiana homeowners. The one figure our calculator could be checked against turns out to be a model output multiplied by an uncited assumption — so it cannot check anything.
Comparison rejected — the only figure our band could be checked against is one nobody measured
Permit data
San Francisco's re-roof permits carry dollar figures that behave like a real distribution rather than a fee table - a median of $16,000 across 5,520 filings. But 94% never state the roof's size, and the figure does not move when the roofing material does, so it cannot check a per-square band in either direction.
Comparison rejected - 94% of filings state no roof size, and the dollar figure does not move with the material
Choosing which records to open is the part of this no automated check can police: a source dropped quietly leaves no trace. So the discards are listed here with the reason each one failed, and the list grows as the section does.
Reddit r/HomeImprovement 등 커뮤니티에 집주인이 올린 견적서
Three separate problems, any one of which is disqualifying. The posts are their authors' copyrighted work, not public records. They routinely carry the city, the house size, and the contractor's name together, which is more identifying detail than we will republish about a private household. And reproducing other people's posts on an ad-supported site is the exact shape of what search engines call scraped content.
Austin, TX 건축 인허가 오픈데이터 (data.austintexas.gov, 3syk-w9eu)
The declared-value field is not usable. A single-family remodel permit issued in June 2026 carries a total job valuation of $1. Rows also arrive with the street address, six-decimal coordinates, and the contractor's phone number attached, so nothing could be quoted at the row level anyway.
NYSERDA 주거 히트펌프·기존주택 프로그램 데이터셋 (data.ny.gov)
The fields are close to ideal — total project cost, home size in square feet, climate zone — and the data stopped moving years ago. Approvals in the heat-pump set end in December 2019; the existing-homes set ends in 2014. Comparing 2014 prices to a 2026 band measures inflation, not our arithmetic.
미 연방 조달 지출 데이터 (USASpending API, NAICS 238160 Roofing Contractors)
The API works, the data is federal and free of licence and privacy problems, and the awards are the wrong size. The largest roofing contracts run to eight figures on federal facilities — two to three orders of magnitude above a house — and the records carry no quantities to normalise by.
Insurance Information Institute — 풍수해 클레임 평균 지급액
The figure is a useful outside reference point, but the page carries an explicit NAIC restriction on further reprint or distribution and a Verisk copyright on the underlying tables. A single sentence with attribution is defensible; rebuilding their table as our own chart is not, so this stays a footnote elsewhere rather than a record of its own.
뉴올리언스 주택청 지붕 교체 입찰 공고 (HANO IFB 26-911-02)
The invitation names sixteen specific rental houses and their scope, but publishes no roof area and no engineer's estimate — the drawings hold both and are not in the public file. Without a denominator the award amount cannot be turned into anything our calculator produces.
We have never re-roofed a house. This site builds calculators, and calling these pages "case studies" would imply site visits, invoices, and clients we do not have. What we do have is the ability to open a public record, run the query in front of you, and say plainly what it does and does not measure.
Each record gets the same six sections: what the record is, what it measures and what it quietly does not, how the cohort was filtered, the distribution against our published band, a verdict, and what the finding means if you are collecting quotes in that jurisdiction. The query is printed in full so you can re-run it and get our numbers or catch us out.
A record lands in one of four places. Band confirmed means the public figures fall inside the range we published before we looked. Band moved means they did not, and we changed the data — the page keeps the original band in print, with the correction dated below it, because a ledger with no corrections is evidence of editing, not of accuracy. Comparison rejected means the record turned out not to measure prices at all, so it cannot judge us either way. Not a band check covers records that are worth reading for a different reason.
Two dates appear at the top of every record: when we retrieved the outside figures, and the asOf stamp on the pricing data behind our band. The second is always earlier, and the commit history behind this site shows it was earlier — the band was fixed before the check, not fitted to it afterwards.
No accuracy score. We will not tell you that our calculators are right some percentage of the time, and you should distrust any cost site that does. Our bands are wide on purpose — a sewer-line estimate spans more than three times from low to high, because that is genuinely how much regional labour, access, and surface restoration move the number. A test of whether real prices land inside a range that wide is a test almost any range would pass. Publishing that as a performance figure would be selling the width of the band as a virtue.
There is also no publishing schedule. This site once claimed a review cadence it could not keep, and the sentence was deleted rather than defended. These records are re-run when the underlying dataset moves enough to change what they say, and left alone when it does not.