Catching roof problems in October or early November — before hard freezes set in — is substantially easier and less expensive than addressing them mid-winter. A damaged shingle edge or loose piece of flashing that causes no visible issue during dry fall weather can allow water infiltration once snow begins to melt and refreeze. This article outlines a methodical approach to fall roof inspection that applies to most Canadian residential roof types.

Starting With the Attic

Many roof problems announce themselves from the inside before they become visible on the exterior. Before climbing onto the roof or even walking the perimeter, inspect the attic space on a clear day with artificial light off. Look for daylight penetrating through the roof deck — any visible light indicates a gap large enough to admit water or vermin. Check the underside of the roof sheathing for staining, discolouration, or mould growth. These signs typically indicate either a chronic leak point or condensation caused by inadequate ventilation.

Attic ventilation deserves particular attention before winter. Insufficient ventilation traps warm, moist air against the cold roof deck. This creates conditions for condensation, accelerates sheathing degradation, and contributes directly to ice dam formation once temperatures stabilise below freezing. Soffit-to-ridge ventilation systems, when clear and unobstructed, maintain air movement that keeps the roof deck temperature closer to outside air temperature.

Note on insulation placement: Insulation that blocks soffit vents negates the ventilation system. Check that baffles are in place at each rafter bay near the eaves, keeping a clear air channel from soffit intake to ridge exhaust.

House with accumulated snow on its roof during winter
Uneven snow distribution on a roof can indicate heat loss through the deck — a warning sign for both energy efficiency and ice dam risk.

Shingle Condition Assessment

From the ground, scan the roof surface with binoculars or from a safe elevated position. Look for:

  • Curling edges or cupping — Shingles that curl upward at the edges or cup in the middle have lost flexibility. They are more likely to crack or blow off under wind and ice loads.
  • Missing granules — Check gutters for accumulation of asphalt granules. Heavy granule loss indicates shingles approaching the end of their service life. The exposed asphalt layer then hardens and cracks faster when temperatures drop.
  • Cracked or broken shingles — Individual cracked shingles can often be replaced without a full re-roof, but multiple cracked units in a concentrated area suggest widespread material degradation.
  • Moss or algae growth — In humid regions (coastal British Columbia, eastern Ontario, Atlantic Canada), biological growth is common. Moss retains moisture and can lift shingle edges over time. Algae discolouration is less structurally critical but indicates persistent moisture.
  • Lifted or displaced shingles — Wind can partially lift shingles that were not adequately fastened, or where nails have backed out due to thermal movement over many seasons. These gaps admit water at precisely the point where wind-driven rain and snow melt tend to concentrate.

Flashing Inspection

Flashing — the metal strips that seal roof penetrations and transitions — is responsible for a disproportionate share of residential roof leaks. Inspect all flashing points systematically:

Chimney Flashing

Step flashing along the sides of the chimney and counter-flashing embedded in the mortar joints should be tight and sealed. Mortar between the counter-flashing and chimney masonry often cracks with age and thermal cycling. Even a narrow crack allows water to track behind the flashing and into the roof assembly.

Pipe Boot Flashings

Plumbing vent stacks exit through the roof and are sealed with a neoprene or lead boot flashing. Neoprene degrades under UV exposure and becomes brittle, cracking at the collar around the pipe. This is one of the most common sources of active leaks in houses over 10–15 years old.

Valley Flashing

Where two roof planes meet, valley flashing handles concentrated water and snow melt runoff. Check that the valley flashing material is intact, not cracked, and that the shingle edges on either side are properly sealed or woven depending on the installation method used.

Eave and Drip Edge

Drip edge flashing along the eaves directs meltwater into gutters rather than behind the fascia. Missing or improperly lapped drip edge is a frequent finding on older houses.

Gutter and Downspout Check

Clear gutters of leaf debris and inspect for sagging sections, loose hanger brackets, or separations at joints. Gutters that hold standing water freeze solid in winter and add considerable weight to the eave overhang. Downspouts should direct water at least 1.5–2 metres from the foundation wall. Extension pieces are inexpensive and straightforward to add before freeze-up.

Exterior Wall and Soffit Transition

Walk the perimeter of the house and look up at the soffit-to-wall transition. Gaps in soffit material allow animal entry into attic space. Paint peeling on exterior walls immediately below roof overhangs can indicate water is tracking back along the soffit due to ice dam pooling above.

Documentation

Photograph any areas of concern with date-stamped images. This creates a baseline for comparing condition in future inspections and supports insurance claims or contractor discussions. Systematic records are particularly useful for rental properties with multiple roofs managed on different schedules.

When to involve a professional: Visible sagging in the roof plane, widespread shingle failure, or any evidence of structural deck compromise warrants an assessment by a qualified roofing contractor or structural engineer before winter loading begins.

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