How do I know the new underlayment went on my Calgary roof?

Most homeowners never see the underlayment go on, because it disappears under the shingles within hours. Here is how to get reasonable confidence it was done correctly, without climbing onto the roof yourself.

What to look for before the shingles go on

The best window is the day of installation. If you can be home, walk around the perimeter while the crew is working. Underlayment is a large roll of material, typically a synthetic sheet or felt, and it covers the entire deck before a single shingle is nailed. You should be able to see it draped across the roof from the ground. Along the eaves, the National Building Code requires a self-adhering modified bitumen membrane (ice-and-water shield) running at least 900 mm up the slope to a point at least 300 mm inside the inner face of the exterior wall. In Calgary's climate, with roughly 128 freeze-thaw cycles a year, this eave protection is not optional and it looks visibly different from the dry-laid underlayment above it: it is thicker, darker and sticks directly to the deck.

If you arrive and the shingles are already on, you have missed the visual window. That is not unusual, but it means you need to rely on documentation.

Before work starts, ask the roofer to photograph the underlayment in place. A professional crew will do this routinely, especially on insurance jobs. The photos should show the ice-and-water shield at the eaves, the lapped rows of underlayment above it, and any valley or penetration details. Ask for these photos as a condition of final payment, not as an afterthought.

Check the quote and invoice. A proper written contract under Alberta's Consumer Protection Act must describe the materials in detail. It should name the underlayment product, specify that ice-and-water shield is included at the eaves (and in valleys if that was agreed), and list the square footage. If the invoice just says "underlayment included" with no product name or quantity, push back before you pay.

Check the attic after the job. From inside, look at the underside of the roof deck with a flashlight. New nails from the shingles should be visible in a consistent pattern across the decking. If you see large gaps in the nail pattern near the eaves, or if the deck looks untouched in places, that can hint at incomplete coverage, though it is not conclusive on its own.

Ask about the leftover materials. A legitimate crew will have empty rolls of underlayment and ice-and-water shield on site or in the bin. The roll labels show the product name and coverage area. If the roofer says they took everything away before you could see it, that is worth noting.

Hold back payment until you are satisfied. Alberta's consumer-protection rules allow you to include a holdback in the contract, and it is wise to do so. Keep a written holdback on part of the total, released after a final walkthrough and receipt of the photos and warranty documents.

If you have a genuine concern that underlayment was skipped entirely, a paid roof inspection by an independent inspector (typically $150 to $400 in Calgary) can sometimes detect it through thermal imaging or by examining exposed areas around flashings and vents, though no inspection method is perfectly conclusive once shingles are down.

The simplest protection is to set the expectation before the job starts: written scope, photos during installation, and a holdback until you have both.