Why Are My Roofing Estimates So Different?

Homeowners often read a wide spread between bids as evidence that someone is lying. Usually nobody is. Three estimates differ because three contractors measured differently, specified differently, staffed differently and carried different overheads - and because at least one of them is probably quoting a different job than the others. Here are the seven reasons, in the order they most often account for the gap.

Reason 1 — They Are Not Quoting The Same Scope

This explains more spread than the other six combined. One estimate includes tear-off, synthetic underlayment, ice-and-water shield in the valleys and at the eaves, new step and counter flashing, new pipe boots, corrected ventilation, the permit and a written workmanship warranty. Another includes shingles over the existing decking with reused flashing.

Both are real prices. They are prices for different products. Until you line the scopes up side by side, the numbers are not comparable in any meaningful sense - and this is precisely why a bottom-line comparison is the wrong tool.

Reason 2 — They Measured Differently

Contractors arrive at square counts by different methods: physical measurement on the roof, aerial or satellite measurement software, or estimation from the ground. These produce different numbers, particularly on complex roofs with multiple planes.

Ask each contractor for their square count. If the counts differ materially, that alone may explain much of the spread. It also tells you who actually got on the roof.

Reason 3 — Different Assumptions About What Is Underneath

Nobody knows the decking condition until the roof is opened. One contractor builds in a substantial decking allowance; another assumes sound decking and handles it by change order. The first bid looks higher and may end up cheaper. The second looks competitive and can climb sharply once the tear-off starts.

Ask each: how many sheets are assumed, what is the per-sheet price, and is unused allowance credited back?

Reason 4 — Material System, Not Just Shingle Brand

Two estimates naming the same shingle can still differ substantially, because the shingle is one component of a system. Underlayment, starter strip, ridge cap, ventilation components and fastener pattern all vary, and enhanced manufacturer warranties typically require the complete system installed to specification.

A bid using cut shingles as starter and minimum nailing may name the same brand as a bid using manufactured starter and the warranty-compliant pattern. Only one of them qualifies for the enhanced warranty.

Reason 5 — Labor Model

A company running its own trained crews with an on-site foreman carries higher fixed costs than one brokering the job to whichever subcontracted crew is available. That difference is real and it shows up in the price.

Neither model is automatically wrong, but you are entitled to know which you are buying, who carries the workers' compensation for the people on your roof, and who your point of contact is on install day.

Reason 6 — Overhead, And What It Buys

A company with a physical local office, employed office staff, insurance, a warranty reserve and a phone answered at 2am costs more to run than a truck and a phone. Some of that overhead is genuinely worth paying for, because it is what makes a warranty claim in year twelve answerable.

The test is whether the overhead delivers something: a real address, a reachable office, a warranty with a company behind it. Our page on why company longevity matters goes into why this is not an abstraction.

Reason 7 — Sales Strategy

Some spread is not about the roof at all. A deliberately low opening figure designed to win the job and grow through change orders. A high figure with room to "discount" theatrically when you hesitate. An inflated number on a storm claim. These are real and they are detectable - the tells are a price that moves under mild pressure, a discount that expires today, and an estimate that resists itemization.

Finding Which Reason Explains Your Spread

A Table To Fill In

Print it, fill it in from the three documents, and the outlier explains itself.

Where We Sit In That Spread

We will not always be the lowest number, and we would rather explain why than pretend otherwise. We run our own crews with a foreman on site, we replace flashing rather than reusing it, we correct ventilation, we pull the permit, and every roof carries a limited lifetime workmanship warranty from a company that has been family-run since 1947 and has served more than 50,000 customers. Those choices have a cost and they are visible in the estimate, itemized, so you can weigh each one yourself.

Common Questions