Why do Calgary roof quotes vary by thousands for the same house?

Price swings of $5,000 to $10,000 between quotes on the same Calgary house are completely normal, and they almost always trace back to differences in what each contractor is actually planning to do, not just what they're charging per shingle.

What's actually driving the gap

Tear-off and disposal is the first place quotes diverge. One contractor may plan to strip both layers of old shingles and haul everything away; another may propose an overlay, laying new shingles on top of the old ones to save a day's labour. Tear-off adds roughly $1 to $4 per square foot, but it also lets the roofer inspect the decking underneath. An overlay hides rot, soft spots and failing sheathing, and it shortens the life of the new roof.

Decking allowance is the second big variable. A quote that includes no allowance for sheathing replacement looks cheaper on paper. A quote that includes, say, 10 sheets of OSB at $65 to $130 per sheet, with a clear per-sheet price for anything beyond that, is more honest about what the job may actually cost once the old shingles come off.

Product choice moves the number significantly. Standard architectural shingles run about $5 to $8.50 per square foot installed; Class 4 impact-resistant shingles, which the City of Calgary says reduce hail damage risk substantially and can cut insurance premiums by up to 50% according to the Insurance Bureau of Canada, run roughly 10 to 20% more. On a typical Calgary house that gap alone can be $2,000 to $4,000.

Eave protection and underlayment are often missing from low quotes. The code's eave-protection minimum is only the start; a proper quote spells out what goes down across the whole roof, not just at the eaves.

Flashings and vent boots are another hidden split. Reusing old flashings around chimneys, skylights and plumbing vents is a common shortcut; replacing them adds cost but prevents the leaks that show up two winters later.

Overhead and warranty round out the gap. A contractor carrying WCB-Alberta coverage, a prepaid contracting licence and proper liability insurance has real costs built into the price. One who doesn't carry those things can quote lower, and you carry the risk. The WCB-Alberta clearance letter is free to request online; if the contractor has no coverage and a worker is hurt on your roof, you could be responsible for outstanding WCB premiums.

How to compare quotes fairly

Line them up scope by scope, not total by total. Each written quote should state the product name and grade, the number of layers being removed, the decking allowance and per-sheet overage price, the type of underlayment and eave protection, whether flashings and vent boots are new or reused, the start and completion dates, the payment schedule, and the warranty terms. Under Alberta's Consumer Protection Act, any contract where a deposit is taken before work is complete must be in writing with a detailed description of the work and materials, itemized prices, the dates and your cancellation rights.

A quote missing half of those items isn't a bargain; it's an incomplete scope that will grow once the roofer is on your roof and finds what's underneath.

If you've had hail damage, get the insurer's adjuster scope before signing anything, and treat any door-to-door offer the morning after a storm with real caution.

If you want more quotes to compare against the ones you have, our form sends your job to local roofers.