What a roof costs

Roofing is priced by the square — 100 square feet of roof surface, not of floor area. Learning that one unit makes every cost figure on this site and every bid you receive readable.

Why we publish ranges instead of averages

Published roofing cost figures disagree by close to a factor of two, and averaging them produces a number that looks precise and means nothing.

The disagreement is real, not sloppiness: labour rates vary several-fold across the country, tear-off of two layers costs materially more than one, a cut-up roof with six valleys takes far longer per square than a simple gable, and decking replacement is unknown until the old roof is off.

So we publish a range from each source, name the source, and label it an estimate. Every cost source we use is a Tier 3 aggregator under our editorial policy, and we never cite one aggregator to another. Where a figure matters to a decision, get three local bids.

Cost by material

The chart and table on our asphalt shingles and other material pages give installed cost per square by covering type, with lifespan alongside it — because cost per year of service is a more honest comparison than cost per square.

The headline shape of it: 3-tab asphalt is the cheapest thing that is still a roof; architectural asphalt is the default for most US homes; metal costs two to four times as much and lasts two to three times as long; tile and slate are a different category of money and usually require a structural evaluation before they are even an option.

What changes the number most

Pitch. A steeper roof has more surface area than the footprint underneath it, and above about 6:12 it also needs staging and fall protection that a walkable roof does not. Both raise the price.

Complexity. Valleys, hips, dormers, skylights and chimneys are where the labour is. A simple gable and a cut-up hip roof of identical area are not the same job.

Layers to remove. Tear-off and disposal of two layers costs meaningfully more than one.

Decking. Unknown until the roof is open. This must be quoted as a per-sheet price in the bid.

Access. A two-storey roof on a tight lot with no truck access costs more than a ranch with a driveway to the eave.

Region. Labour is the largest single input and it varies more than material does.

Check the square count before you compare prices

The most common reason two bids differ is that they are quoting different amounts of roof.

Measure your footprint, apply the pitch multiplier, and check the result against each bid using the roof area and squares calculator. If a bid’s square count is well below your own figure, either they measured the footprint instead of the roof surface, or they are quoting less than the whole roof.

Repair or replace

A repair is usually the right answer when the damage is localized, the rest of the roof has substantial life left, and the cause is understood. It is usually the wrong answer when the covering is at the end of its service life, because you are paying for access to a roof that needs replacing anyway.

The honest test is not the size of the damage but the age of the roof. Patching a 22-year-old asphalt roof buys a season and costs you the same access twice.

Be sceptical of a replacement recommendation from whoever is also going to sell you the replacement — that is not an accusation, it is just how incentives work, and it is why we treat contractor-published content as Tier 3.

Financing, and the deductible

If a claim is involved, the insurance section covers why the first cheque is smaller than the estimate and what recoverable depreciation is. The short version: replacement cost minus depreciation minus your deductible is what arrives first, and on a replacement cost policy the rest is released after the work is done.

Anyone offering to make your deductible disappear is proposing insurance fraud that exposes you too. See hiring a roofer.