Price it in squares of roof surface, never squares of footprint. Multiply the footprint by the pitch factor, add waste by roof shape, then price labor per square from what your crew really lays in a day, with tear-off as a separate line per layer. The two places a roofing bid loses money are the pitch and the layers. Skip the 1.202 factor on an 8/12 roof and a 2,000 square foot footprint is bid at 20 squares when it is 24. Miss a second layer from the driveway and, at the $100 to $150 per square per layer that Gorilla Roofing publishes for 2026 tear-off, you have given away $2,400 to $3,600 on that same roof.
How big is a roofing square?
One hundred square feet of roof surface, measured on the slope. That is the whole definition, and it is why the ground measurement is only a starting point. GAF packs its Timberline HDZ at three bundles and 64 pieces per square, nailed at 256 to the square. Once you have squares, you have the order.
"Roofing square size" is a rising query on Google Trends this year. The answer that should come with it is that a square of roof is bigger than a square of house.
How do you turn a footprint into roof area?
Measure the footprint with the overhangs included, then multiply by the pitch factor. The factor is the square root of one plus (rise ÷ 12) squared. You do not need a chart for it, but here is one.
| Pitch | Factor | 2,000 sq ft footprint becomes | Squares |
|---|---|---|---|
| 4/12 | 1.054 | 2,108 sq ft | 21.1 |
| 6/12 | 1.118 | 2,236 sq ft | 22.4 |
| 8/12 | 1.202 | 2,404 sq ft | 24.0 |
| 10/12 | 1.302 | 2,604 sq ft | 26.0 |
| 12/12 | 1.414 | 2,828 sq ft | 28.3 |
Where this goes wrong: the overhang. A 16-inch overhang all the way round a 40 by 50 house adds about 247 square feet of footprint, which is nearly three squares on an 8/12. Measure the drip edge, not the wall.
Where it goes wrong a second time: one pitch for the whole roof. A 10/12 main roof with a 4/12 porch tie-in is two calculations. Average them and you are wrong on both.
How much waste do you add?
Set it by the shape of the roof, not by habit. 1ESX's 2026 guide puts a simple gable at 5 to 10%, a mix of hips and gables at 10 to 15%, and cut-up roofs with dormers and valleys at 15 to 20% or more, with each major hip or valley adding 1 to 2%.
Take the 8/12 example as a hip roof at 15%. Twenty-four squares becomes 27.6, so you order 28 squares: 84 bundles and about 7,200 nails at GAF's 256 a square.
Starter and ridge cap are not in that waste number. Count them by the linear foot and order them as their own lines. Starter runs the eaves and rakes. Cap runs the hips and ridges. A flat percentage that "covers accessories" is how you end up sending someone to the supply house at 2pm with the crew standing on the roof.
How do you work out labor per square?
Divide what your crew costs for a day by the squares it lays in a day on that kind of roof. That is the only number that is yours. Published ranges give you a sanity check, not a price.
BLS put the median roofer at $55,440 a year in May 2025, about $26.65 an hour. Put 35% on top for payroll burden as a placeholder, knowing roofing comp is one of the most expensive classes there is and yours may be well above that. A four-man crew for eight hours then costs about $1,151 a day.
| Roof | Squares per crew day | Labor cost per square |
|---|---|---|
| Walkable gable, 4/12 to 6/12 | 20 | $57.56 |
| Hip roof, 8/12, some valleys | 14 | $82.23 |
| Cut-up roof, 10/12 and up | 10 | $115.13 |
The production numbers are illustrative. Time your own crew on three roofs and replace them.
Now compare that cost with what gets charged. SubcontractorHub lists 2026 asphalt labor at $150 to $300 a square. The gap between $57 of crew cost and $150 of labor price is your overhead and profit: the trucks, the dumpster, the office, the warranty callbacks, your own salary. Contractors who bid labor at crew cost are not cheaper than the market. They are working for free and do not know it yet.
What does a steep roof add?
Time, gear, and sometimes another man. OSHA defines a steep roof as anything over 4 in 12, and residential work requires fall protection at 6 feet or more above a lower level. Anchors and roof jacks go up before a single shingle does. That is paid time.
SubcontractorHub puts the steep-roof labor adder at 20 to 50%. Two things decide where you land in that range. Can a man stand on it without jacks, and how much of the day goes to moving the jacks? An 8/12 is walkable for most crews. A 12/12 is not. Every course gets set from a staging board.
Price the adder per square on the steep sections only. A two-story with a 12/12 front gable and a 6/12 back is a 6/12 roof with a steep section, not a steep roof.
How do you price tear-off per layer?
As its own line, per square, per layer. Gorilla Roofing puts 2026 tear-off at $100 to $150 per square for each layer removed. Never fold it into the install price, because the number of layers is the one thing on a roof you cannot reliably see from the ground.
Here is the rule that makes it matter. Under IRC R908.3.1.1, a roof cannot be recovered where the existing roof already has two or more applications of any covering. Find a second layer and the job is a full tear-off to the deck, whatever you wrote down. No exceptions.
So check before you price. Get on the roof, or at least up a ladder at the rake edge, and look at the edge where the shingles meet the drip edge. Two stacked edges, a thick lumpy line at the rake, or a second set of shingle tabs under a lifted corner all mean two layers. Look at a plumbing boot too. A boot sitting low in a deep collar is often a boot that was flashed over an old layer.
Then write the deck as a unit price, because you will not see it until the shingles are off. "Includes up to two sheets of 7/16 OSB replaced; additional sheets at $X per sheet installed." Old 1x board decking with gaps between boards is a separate conversation. Asphalt shingles need solid sheathing, so a house that once had wood shakes over spaced boards may need a full re-deck. That one you can usually spot from the attic with a flashlight before you bid.
How do you price disposal?
By weight, because the hauler bills you by the ton. Dumpsters.com lists three-tab at 230 to 250 pounds per square and architectural at 400 to 430. Other published figures for architectural run well below that, so treat the range as a ceiling and check it against the scale tickets from your last three jobs.
Do the math. Twenty-four squares of two-layer three-tab at 250 pounds is 12,000 pounds, six tons. The same roof with one layer is three. That is a second dumpster or an overweight charge, and it belongs in the same per-layer line as the tear-off labor.
What this misses
The published ranges are national. Labor per square in Phoenix and in Boston are not the same number, and neither source breaks it down by metro. Use them to check your own build, never as the build.
Comp is the variable that swings most. The 35% burden above is a placeholder. Roofing comp rates vary widely from state to state, so price from your own policy.
Metal, tile and low-slope membrane are different jobs. The pitch factor and the layer rule carry over. The production rates and the material math do not.
Satellite measurement reports help with area, not with layers. They will give you a clean pitch and square count. They cannot tell you what is under the top shingle.
If you price labor like any other crew, the labor pricing method works the same way here. The deck clause and the layer line are the kind of thing that belongs in what you exclude from the estimate and, when it turns up anyway, in a written change order. BidWalk puts the layer count, the pitch and the deck clause on the estimate while you are still up the ladder looking at the rake edge, so the second layer gets priced before the dumpster arrives.
