How to Compare Roof Replacement Quotes

Getting three quotes for a new roof is good advice. Making sense of them is harder. One arrives as a single line with a total, another runs to two pages of product names, and the third is somewhere in between. The totals differ, the wording differs, and it’s rarely clear whether the cheaper one is a bargain or a smaller job. This guide gives Airdrie homeowners a practical method: rebuild each quote into the same set of lines, fill the gaps with questions, and only then compare the numbers.

Why totals alone mislead

A roof replacement is a bundle of separate decisions: how much gets torn off, what goes under the shingles, how the edges and walls are sealed, how the attic breathes and what happens if the deck is rotten. Each contractor makes those decisions differently, and each one moves the price.

In Airdrie, where most homes were built in the last twenty-five years with builder-grade shingles, the weather exposes weak decisions quickly. Hail from storms that track east off the foothills, north and northwest winds lifting rake edges, and chinooks that melt and refreeze roof snow all winter all find the details a low quote skipped. As a reference point, a standard architectural asphalt replacement on a typical 1,600 to 2,000 sq ft Airdrie home often lands somewhere around $10,000–13,000 (2026 Airdrie market estimates), with complexity, pitch and extras pushing it up or down. If one quote sits well below the others, the question isn’t “why are they so expensive?” but “what did the low one leave out?”

For a broader look at price ranges by material and roof type, the Airdrie roofing cost guide covers the numbers. This article is about the method.

Step 1: Check how each roofer measured

Every quote starts with a measurement, and differences here ripple through the whole price.

• Did they get on the roof or up a ladder? A measurement from a satellite image or from the curb can miss dormers, a steep back slope or a second layer of shingles.
• Are they quoting in roofing squares or square feet of roof? Roof area is not the home’s floor area. Pitch, overhangs and garage roofs all add to it.
• Is waste included? Hips, valleys and cut-up rooflines need more material than a simple gable.
• Did anyone look in the attic? Ventilation and moisture problems change what the roof needs, and they’re invisible from outside.

If two quotes show very different roof areas for the same house, ask each company to explain their number. One of them is wrong, and the answer will tell you something about their care.

Step 2: Tear-off or roof-over

This is the first line to pin down. A roof-over installs new shingles on top of the old layer. It saves labour and disposal today, but it hides the deck from inspection, adds weight, can shorten the life of the new shingles and doubles the tear-off next time. On older homes in Old Town, a quote may also need to allow for a hidden second layer already on the roof.

Ask each contractor in writing: are you removing every existing layer down to the deck? If one quote is a roof-over and the others aren’t, you aren’t comparing like with like.

Step 3: Deck repairs and how they’re priced

Nobody knows exactly how much sheathing is soft or rotten until the old roof is off. That makes deck repair the most common source of surprise on the final invoice. A good quote handles it openly:

• It states a price per sheet of replacement decking.
• It says whether any sheets are included in the base price, and how many.
• It commits to showing you photos of damaged decking before it’s replaced.

A quote that says nothing about decking isn’t cheaper; it’s silent. Put the per-sheet prices from each quote side by side, and imagine the same number of sheets on each, so the totals are comparable.

Step 4: Ice-and-water shield coverage

Ice-and-water shield is a self-adhering membrane that seals around nails and stops water that backs up under the shingles. In Airdrie, where chinooks melt snow on the upper roof and ice builds at the eaves, where it goes matters.

Compare exactly where each quote puts it:

• Along the eaves, and how far up the roof from the edge
• In every valley
• Around chimneys, skylights and walls where the roof meets siding
• Across low-slope sections, where standard underlayment isn’t enough

“Ice-and-water shield included” with no locations is a question, not an answer.

Step 5: Starter strip on the rakes as well as the eaves

Starter strip along the eaves is standard. Starter along the rakes, the sloped side edges of each gable, often isn’t, and it’s where Airdrie’s wind gets under shingles first. On exposed lots at the edges of the city, and in communities facing open farmland like Reunion, rake starter combined with the manufacturer’s high-wind nailing pattern and hand-sealing in cool weather is the difference between an edge that holds and one that peels.

Ask each roofer whether starter goes on the rakes and which nailing pattern they’ll use.

Step 6: Flashing, new or reused

Flashing is the metal that seals the roof where it meets walls, chimneys, skylights and other roofs. The most common leak on a typical Airdrie two-storey is where the attached garage roof meets the front wall of the house, and it almost always comes down to short or missing flashing.

Look for clear answers on:

• Step flashing along walls: new, or reused?
• Kick-out flashing at the bottom of each roof-to-wall junction
• Chimney flashing: new counter-flashing, or caulk over the old?
• Vent boots around plumbing stacks: all replaced?
• Drip edge on eaves and rakes

Reused flashing isn’t always wrong if it’s in good shape, but it should be a decision the roofer explains, not a silent saving.

Step 7: Ventilation

A roof that runs hot in summer and damp in winter wears out early and invites ice dams and attic frost. Alberta’s building code calls for at least 1 sq ft of attic vent area for every 300 sq ft of insulated ceiling, split between intake and exhaust.

Compare whether each quote mentions ventilation at all, whether exhaust (ridge vent or roof vents) is balanced with intake vents under the eaves, and whether anyone noticed bathroom fans venting into the attic. Fixing ventilation during a replacement costs far less than doing it later. The roof replacement page explains how ventilation fits into a full replacement.

Step 8: Shingle line and impact class

“Architectural shingles” covers a wide range of products. Ask for the manufacturer, the exact product line and the colour, in writing. Two quotes can both say “30-year shingle” and be quoting quite different products.

In Airdrie’s hail corridor, also ask whether the quote is for a standard shingle or a Class 4 impact-resistant one, meaning it passed the UL 2218 test of a 2-inch steel ball dropped twice on the same spot without cracking. Class 4 asphalt typically runs about $6–8/sq ft installed on a straightforward roof (2026 Airdrie market estimates), compared with roughly $5–6.50/sq ft for a comparable standard installation. If one quote is Class 4 and another isn’t, price them both ways so you’re comparing the same product. Some Alberta insurers offer a credit for documented Class 4 roofs, but it’s never automatic and varies by insurer, so check with your own broker.

Step 9: Disposal, cleanup, GST and the payment schedule

These lines look boring and cause most of the arguments.

• Disposal: is the bin included, and is a second layer’s extra weight?
• Cleanup: is a magnetic nail sweep of the lawn, beds and driveway included, daily and at the end?
• GST: is it included in the total, or added on top? A quote that looks lower because it’s before tax isn’t lower.
• Payment schedule: how much is due when? Most of the payment should follow the work. In Alberta, contractors who take payment before finishing generally need a prepaid contracting licence, so a large deposit is worth asking about.

Step 10: Warranty in writing

Ask for two things on paper: the manufacturer’s warranty for the materials, and the contractor’s own workmanship warranty for the installation. Compare their length, what they exclude, whether they transfer to a buyer and how you make a claim. A workmanship warranty is only as good as the company’s likelihood of answering the phone years from now, which is why the guide on how to choose a roofing company is a useful companion to this one.

A side-by-side comparison worksheet

Copy this structure onto paper or a spreadsheet and fill in one column per quote. The entries below are an illustrative example of how two different quotes might read, not real quotes, and they show why filling in every row matters.

Once every row is filled, the gaps become obvious. Each “not stated” is a phone call to make before you can compare totals.

Why the cheapest quote often isn’t

Once the worksheet is complete, go back through the low quote and price in what it’s missing. A composite example of what often happens: the lowest quote left out rake starter, reused the wall flashing, didn’t mention ventilation and priced decking at zero because it said nothing about it. Add realistic deck repairs, the missing flashing and a ventilation fix, and the gap to the next quote shrinks or disappears, while the roof you’d get still has weaker edges.

Cheap roofs in Airdrie tend to fail in predictable places: shingles lifting along the rakes after a northwest windstorm, a stain on the garage ceiling where the roof meets the wall, water at the eaves during the first chinook. Each of those repairs costs money and a service call. Over a roof’s 15 to 20 year life, the quote with every line filled in is often the less expensive one.

Putting it into practice

Ask every roofer for an itemized written quote, fill in the worksheet, and call to close every blank before you compare the bottom line. If you’d like one more itemized quote to lay beside the others, you can book a free estimate and use it however you like, including as a benchmark.