My shingles are 15 years old and bald in spots, Calgary, replace?

Fifteen-year-old shingles with bare spots are telling you they're done. In Calgary, a full asphalt shingle replacement runs roughly $10,000 to $24,000 for a typical detached house, based on about $5 to $8.50 per square foot of roof area.

Is replacement the right call?

Granule loss that exposes the mat underneath is not cosmetic. Those granules shield the asphalt from UV and shed water; once they're gone, the shingle dries out, cracks and curls quickly. At 15 years, most architectural shingles are past the halfway point of their useful life in Calgary's climate. Patching bald spots buys a season or two at best, and a roofer quoting repairs will likely tell you the same after seeing the rest of the roof. A full replacement is almost always the better investment at this stage.

What moves the price for your job: roof size in squares (a "square" is 100 square feet), pitch and height, how many layers are already on the deck, and the condition of the sheathing underneath. If there's a second layer of old shingles, tear-off adds roughly $1 to $4 per square foot. Damaged or soft decking boards run about $2 to $4 per square foot to replace, usually quoted per sheet beyond a small included allowance. Flashings, valley metal, vent boots and ridge venting are separate line items; ask that each one be listed in the quote.

Calgary's climate adds a couple of things worth knowing. The city sits in what the City of Calgary calls "hail alley," so this is a good moment to ask about Class 4 impact-resistant shingles. They cost roughly 10 to 20% more than standard architectural shingles, but the Insurance Bureau of Canada says a majority of insurers offer discounts of up to 50% on home insurance premiums for hail-resistant materials. Ask your insurer what discount applies before you choose a shingle. The National Building Code also requires a continuous eave protection membrane (ice-and-water shield) extending at least 900 mm up the slope and to a line at least 300 mm inside the inner face of the exterior wall on Calgary roofs; confirm that's included in every quote, not just the cheapest one.

On permits: replacing asphalt shingles with asphalt shingles is like-for-like re-roofing. Under Alberta's Permit Regulation, that does not require a building permit from the City of Calgary, provided there's no structural work and no change to the type of material.

Before you sign anything, check that the contractor holds an Alberta prepaid contracting licence (searchable on Service Alberta's website) if they're asking for any deposit before the work is finished. Also request a WCB-Alberta clearance letter; if a worker is injured on your property and the contractor has no WCB coverage, you could be responsible for outstanding premiums. The contract itself should spell out the shingle product and class, tear-off and disposal, decking allowance and the per-sheet price beyond it, eave protection, flashings, start and completion dates, payment schedule, and warranty terms. Keep a written holdback until the work passes your inspection.

Bald patches are a good reason to get quotes this season rather than next, and our form is a free way to start.