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Roofing costs: what actually affects the price

Roofing is quoted by the square (one hundred square feet of roof surface) and the number of squares is only the starting point. Two houses with identical footprints can differ by a factor of two once pitch, layers and access are counted.

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The short version

  • Roofing is priced by the square, which is 100 square feet of roof surface, not of floor plan.
  • Eight things move the total: area, pitch, tear-off and layers, deck repair, material grade, complexity, access, and permits and local rules.
  • Deck repair is the most common change order, because nobody knows the deck’s condition until the old covering is off. Get the per-sheet rate in writing first.
  • A quote that states only one number cannot be compared with another quote that states only one number.
  • We do not publish a national average per square, because regional labour and disposal rates move it too far to be useful.

Why there is no headline number on this page. We do not publish a national average price per square. Regional labour, disposal fees and material availability move it enough that a national figure would mislead more than it helps. The references below cover the technical standards a quote should meet.

The eight things that move the price

FactorWhy it moves the number
Roof area in squaresMeasured on the roof surface, not the floor plan. A steep roof has far more surface than the house beneath it.
Pitch and walkabilityPast a certain slope crews need staging and fall protection, which changes the labour line permanently.
Tear-off and layersRemoving and disposing of the old covering is labour plus dumpster. Two existing layers doubles that work.
Deck repairPriced per sheet and discovered after tear-off. Always ask what the rate is before the roof is opened.
Material and gradeThe covering itself, plus underlayment, ice barrier, drip edge, ridge and starter: the accessories are not optional.
ComplexityValleys, dormers, skylights, chimneys and multiple planes each add flashing, cuts and time.
Access and siteDriveway distance, landscaping to protect, two storeys versus one, and where the dumpster can sit.
Permits and local rulesPermit fees, inspections and any local requirement such as an ice barrier line or wind-uplift fastening pattern.

The shape of the arithmetic

Roof area (squares)× installed price per square
+ tear-off and disposal+ deck repair at the quoted rate
+ flashing, vents, accessories+ permit and inspection
= project totalcompare like scopes, not like headlines

Ask every bidder to state squares, layers to remove, deck repair rate and accessories separately. Quotes that give only a single number cannot be compared.

The line that surprises people: deck repair

Sheathing is what everything else fastens to, and nobody knows its condition until the old covering is off. That makes deck repair the most common change order on a roofing job and the easiest place for a quote to be quietly incomplete.

Ask for the rate per sheet before the roof is opened, and ask what the company’s estimate of sheets is based on what it saw. A quote with no deck rate is not cheaper; it is unfinished.

What a comparable quote contains

  • Roof area in squares, stated as a number.
  • How many layers are being removed, and disposal.
  • The deck repair rate per sheet.
  • Underlayment type, and ice barrier where required: at eaves, at valleys, or both.
  • Drip edge, starter course, ridge and every accessory, listed rather than assumed.
  • Which flashing is being replaced and which is being reused.
  • Ventilation: what intake and exhaust the job will leave you with.
  • Permit, inspection and who pulls it.
  • Both warranties: manufacturer on the material, contractor on the workmanship, with lengths.

Cost by project

Cost guides for individual projects and materials are being written. Until each one exists, the calculators below are the more useful route because they let you put your own local rates in rather than read someone else’s.

Work out your own numbers

Common questions

How much does a new roof cost?

There is no national answer worth acting on, and we deliberately do not publish one. Roofing is priced by the square (one hundred square feet of roof surface) and the total is driven by area, pitch, how many layers come off, deck repairs found after tear-off, the covering and accessories, complexity such as valleys and skylights, access, and permit costs. Regional labour and disposal rates move the result far enough that a single national figure misleads more than it helps.

What is a roofing square?

One hundred square feet of roof surface. It is measured on the roof, not on the floor plan, so a steeply pitched house has considerably more squares than its footprint suggests. Quotes are built from squares, which is why a quote that does not state them cannot be compared with another one.

Why are roofing quotes so different from each other?

Usually because they are not quoting the same work. One includes full tear-off and the other assumes a layover; one replaces all flashing and the other reuses what looks sound; one states a deck repair rate and the other leaves it to a change order. Comparing totals before comparing scopes is how homeowners end up choosing the quote with the most exclusions.

Should I get three roofing quotes?

Yes, and hand all three the same written scope. Three quotes against three different scopes tells you nothing except which company is most optimistic about what it can leave out.

Related: every roofing service explained · repair or replace · roofing materials compared · choosing a roofer · find a roofing professional.

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