How to Estimate a Roofing Job

1. 1

   Measure the shape, not just the area

   Squares are the headline, but linear feet of hip, ridge, valley, rake and eave drive the accessory list and the labor, and penetration count drives the flashing line. A 28-square simple gable and a 28-square cut-up hip roof should not carry the same price.

2. 2

   Do a real takeoff, then price material from a live quote

   Field shingles, starter, hip and ridge, underlayment, ice barrier, drip edge, valley metal, step and counterflashing, boots, ridge vent, fasteners, sealant — quantities, not guesses. Then price it today. If your estimate is good for thirty days, your supplier price needs to be too.

3. 3

   Cost the labor from your own production history

   Squares per crew-day for this roof type, at this pitch and storey height, times what a crew-day genuinely costs you with burden on it. Nobody can give you this number, and it decides everything.

4. 4

   Add the job costs that are neither material nor labor

   Disposal, permit, delivery and rooftop loading, equipment rental, fuel and drive time, temporary protection, and sales commission if a rep sold it.

5. 5

   Apply overhead recovery and the margin you need

   Then check the result against the market. If the market number is lower, that is information about your cost structure — not a reason to cut the margin.

A tape and a ladder is still the most accurate method on a roof you can safely walk, and the only one that shows you the decking, the layers, the soft spots and the rotten fascia. It is also slow, and on a steep or three-storey roof it is a bad trade. Ground measurement plus a pitch multiplier is the fallback: footprint, plus overhangs, pitch taken with a gauge or a level and tape in the attic, then multiply. A 6:12 roof has roughly 12% more surface than its footprint; a 12:12 about 41% more. Getting the pitch wrong by two increments on a big roof is a several-square error — on a tight bid, the whole margin.

Aerial and photogrammetric reports — EagleView, Hover, RoofSnap, GAF’s QuickMeasure, the reports Roofr sells — buy speed and a defensible diagram, and are very good at area, hip, ridge, valley and pitch. They cannot tell you the north slope has two layers, the deck is spaced board, or the access is blocked by a sunroom. Treat a report as a takeoff, never as an inspection.

“Add 10%” fits exactly one roof: a simple gable with two planes and no valleys. Waste comes from cutting, and cutting happens at rakes, valleys, hips and obstructions.

• ●Simple gable, long runs, few penetrations: the low end of your range — there is nowhere for material to go except onto the roof.
• ●Hip roofs and multiple valleys: materially more, and the hip and ridge cap quantity rises at the same time — a separate line item at a much higher price per linear foot than field shingle.
• ●Closed-cut valleys consume more shingle; open valleys consume valley metal instead. A cost difference, not a preference — the valley article covers which you want. Directional designer laminates raise waste again, because the cut-off cannot be flipped and reused.

A missing line item does not reduce the price of the job — it moves that cost out of the estimate and into your margin.

People search for “roofing labor cost per square,” and there is no national answer worth having. It varies by region, by self-perform versus sub, by pitch, storey height, material and pay structure — anyone quoting a single figure is quoting the market they happen to work in. What you can do is derive your own, from two inputs.

1. The burdened cost of a crew-day

Take the crew’s base wages for a day and add everything the wage triggers. Employer FICA is 7.65% of wages (6.2% Social Security plus 1.45% Medicare). On top sit federal and state unemployment tax, workers’ compensation premium, and any general liability premium rated on payroll. Roofing is one of the more expensive workers’ compensation classifications in most states, and the spread between states is wide enough that a borrowed burden factor is meaningless. Take your real rates off your policy declaration and your state notice, compute a multiplier, and use it every time.

2. Your crew’s real production rate

Squares per crew-day, recorded separately for tear-off and install and separately by roof type. Do not use a number from a forum — time three of your own jobs, a simple gable, a hip and something cut up, and you have a production table that is right for your crew.

Burdened crew-day cost divided by squares per crew-day gives labor cost per square — the backbone of every estimate you write. If you sub your labor out the arithmetic is simpler, but confirm the sub’s insurance: an uninsured sub’s payroll can land on your workers’ compensation audit as if they were yours.

Overhead is everything that does not attach to a job: truck payment, insurance, office, software, phone, the estimator’s salary, your own pay if you are not on the roof. Total it annually, divide by expected annual revenue, and you have the share of every dollar that overhead consumes before profit exists.

Then the mistake. Marking a job up 20% does not produce a 20% gross margin — markup is measured against cost, margin against price, and the gap is not academic.