How to Read a Roofing Estimate Line by Line

Most homeowners replace a roof once or twice in their lives, which means almost nobody has practice reading a roofing estimate. Three companies hand you three numbers, the numbers are thousands of dollars apart, and there is no obvious way to tell whether the cheapest one is a bargain or a warning. This guide walks through what should appear on a real estimate and what it means, so you can compare bids on substance instead of guessing.

Squares, pitch, and why the size number varies

Roofers measure in squares, and one square is one hundred square feet of roof surface. The first thing worth checking is whether every bid lists a similar number of squares. If one company says twenty-eight and another says thirty-four for the same house, somebody measured from the ground or somebody included the detached garage. Pitch matters too, since a steep roof costs more to work on safely and takes longer. A bid that does not state the squares and the pitch is not really an estimate, it is a guess with a dollar sign on it.

Tear-off versus going over the old roof

A complete estimate says whether the old shingles are being removed down to the deck or whether new shingles are being installed over the existing layer. Going over is cheaper today and more expensive over the life of the roof: it hides rotten decking, adds weight, traps heat, shortens the new roof's life, and can void the manufacturer warranty. If one bid is dramatically lower than the others, this is often why.

Decking: the line that causes most surprise bills

Nobody knows the condition of the wood under your shingles until the old roof comes off. That is normal. What is not acceptable is an estimate that stays silent about it. A good estimate states a per-sheet price for replacing damaged decking so that if the crew finds soft plywood, you already know what it costs. Without that line, you are exposed to whatever number gets quoted while your roof is open, which is the worst possible moment to negotiate.

Underlayment, ice barrier, and drip edge

Beneath the shingles, a proper estimate lists synthetic underlayment rather than old-style felt, ice-and-water membrane in the valleys and around penetrations and along the eaves in cold climates, and new drip edge metal at the eaves and rakes. These items are inexpensive relative to the whole job and they are exactly where corner-cutting happens, because once the shingles are on, nobody can see whether they were installed.

Flashing, boots, and ventilation

Look for new pipe boots rather than reusing the old ones, and look for flashing to be replaced and properly layered at walls, chimneys, and skylights rather than sealed with caulk. Caulk is a temporary repair, not a flashing method. The estimate should also address attic ventilation, both intake at the soffits and exhaust at the ridge, since a poorly ventilated attic will shorten the life of the roof you just paid for.

Warranty language, and what to ask before signing

There are two warranties: the manufacturer's warranty on the materials and the roofer's warranty on the workmanship. Most leaks come from installation, not from defective shingles, so the workmanship warranty is the one that protects you. Ask how long it lasts and what it actually covers, in writing. Then ask three more questions: is the crew employed by the company or subcontracted, is the company licensed and insured with certificates you can see, and what is the payment schedule. A large deposit demanded before any material arrives is a reason to slow down.

Comparing three bids fairly

Put the bids side by side and compare squares, tear-off scope, decking price, underlayment type, flashing and boot replacement, ventilation work, and warranty terms. Very often the cheapest bid turns out to be missing several of those lines rather than being genuinely more efficient. The goal is not to find the lowest number, it is to find the bid where you understand exactly what you are buying.

← Back to all posts