Free Roof Estimate Calculator

How to read a roofer's written estimate

A written roofing estimate should let you rebuild the total from its parts. If it cannot, it is a price rather than an estimate, and a price cannot be compared with anything. Work down it in this order.

• The size. Roofers price by the square, 100 square feet of roof surface, and the quote should say how many squares it covers. Compare that with the sheet above. A count more than about 10% higher deserves a question: dormers, valleys and a generous waste allowance add squares legitimately, while a measurement taken off the floor plan rather than the roof does not.
• Materials by name. "Architectural shingles" is not a specification. The product line and color should be written down, along with the underlayment (synthetic or felt), where the ice and water shield goes, and whether drip edge, starter and ridge cap are new. Substitutions happen where line items are vague.
• Labor and tear-off as separate lines. Installation and removal are different work. A second layer coming off costs about half again the first, so a quote that folds tear-off into one figure should still say how many layers it assumes.
• Disposal and the permit. The dumpster, the haul-away and the permit fee are real costs that someone pays. They belong on the quote, or excluded from it in writing.
• Flashing and ventilation. Whether the step flashing, chimney flashing, pipe boots and vents are reused or replaced. "Reuse where possible" leaves the decision to the crew on the day.
• Warranty and payment. The manufacturer's warranty on the material, the contractor's workmanship warranty on the installation, and a payment schedule. A deposit of 10 to 30% is normal.

Change-order traps to close before you sign

Most disputes on a roofing job are not about the quoted price. They are about what gets added once the old roof is off and the crew is on site, which is exactly when you are least able to say no. Each of these can be priced in writing before the work starts.

• Rotten decking, charged per sheet. Nobody can see the deck until tear-off, so the answer is not to guess how many sheets will fail but to agree the rate. Our dataset puts a replaced 4×8 sheet at $62 to $101 installed. A quote with no per-sheet figure leaves that number to be set on the day, by the person sending the invoice.
• A layer nobody mentioned. If the quote assumes one layer and the crew finds two, removal costs about half again as much. Ask for the price of an additional layer per square before signing.
• "As needed" items. Flashing, vent boots and fascia repairs written as "replace as needed" are open-ended. Ask for a unit price on each.
• Steep or high work. A steep-slope or second-story charge belongs on the original quote as its own line, not on a change order. This calculator does not model it, because published figures vary too widely to price honestly; see the 12/12 pitch page for why it exists.
• Disposal overage. Some quotes cap debris at one dumpster. A heavy tear-off, such as two layers or old wood shakes, can fill a second.

Put the agreed rates in the contract, not in a text message. A change-order rate you agreed while you could still walk away is a very different number from one quoted with your roof open to the sky.

Comparing three quotes on equal terms

Three totals side by side say very little, because three roofers rarely price the same job. One includes a decking allowance, one assumes the second layer stays, one quotes a better shingle. Make the scopes match before comparing the prices.

1. Put them on the same size. Divide each total by the squares it states. That price per square, not the total, is the figure to compare, and the checker above does the division for you.
2. List what each one leaves out. Tear-off layers, disposal, the permit, decking, ice and water shield, new flashing. Mark every line one quote has and another does not, then ask the others to price it.
3. Match the materials. If one quote is for a premium shingle line and the others are not, ask all three for the same line, or at least for the price of the upgrade.
4. Weigh the warranties last. A ten-year workmanship warranty against a two-year one is worth paying something for, because most roof failures are installation failures rather than material ones.

A quote well below the other two, and below the estimate here, has usually left something out rather than found a cheaper way to do the work. One well above usually has a reason you can name: a steep roof, difficult access, a premium product, or a contractor with a full schedule. Ask for the reason. A good roofer can give it line by line.

Six questions that protect you before you sign

• Are you licensed here, and can I see the number? Most states license roofing contractors, and the number should be verifiable on your state board's website in under a minute.
• Do you carry general liability and workers' compensation? Ask for certificates, not assurances. Roofing has one of the highest injury rates in construction, and an uninsured worker hurt on your roof can become a claim against your homeowner's policy.
• Who pulls the permit? The contractor should, in their name. A permit pulled by the homeowner generally makes you the party responsible for the work passing inspection.
• Will your own crew do the work? Subcontracting is common and not a problem in itself, but the crew on your roof should be covered by the same insurance and the same workmanship warranty as the company you signed with.
• What does cleanup include? Tarps over planting beds, a magnetic sweep for nails across the yard and driveway, and the debris gone the day the job ends.
• Will you give me lien waivers? In most states an unpaid supplier or subcontractor can file a lien against your house even after you have paid the roofer in full. A lien waiver with each payment closes that door.