Situation
A viaduct collapse in Quebec City on July 30, 2026, killed one person and injured several others. The driver reportedly lost consciousness at the wheel, according to reporting from Journal de Québec. The incident raised questions about infrastructure inspection standards across the province. Homeowners with tile roofs started asking whether their own structures could hide similar risks. Ice damming is one such risk, and it develops slowly, often out of sight.
Tile roofs are common in Quebec's older residential neighbourhoods. They perform well under snow load when installed correctly. But a tile roof is only as sound as the deck and framing beneath it. Water that freezes and thaws at the eaves can work its way under tiles. Over time, this weakens the roof assembly. A certified inspection is the only way to know what is happening under the surface.
Approach
RBQ certification matters here. The Régie du bâtiment du Québec licenses contractors who meet provincial standards for roofing work. An RBQ-certified inspector follows a defined checklist for tile roofs. The checklist covers tile condition, flashing, underlayment, ventilation, and structural connections. Each item gets a written finding. The report also notes whether ice damming is present or likely.
Ice damming forms when heat escapes from the living space into the attic. That heat melts snow on the upper roof. Meltwater runs down to the cold eaves and refreezes. A ridge of ice builds up. More meltwater pools behind it. The water can then back up under the tiles. Once under the tiles, it can reach the underlayment and deck. Repeated freeze-thaw cycles cause cracks and rot. The roof's structural capacity drops.
Ventilation is the first line of defence. A properly vented attic keeps the roof deck cold. Cold decks do not melt snow unevenly. That reduces ice dam formation. Tile roofs need both intake vents at the eaves and exhaust vents near the ridge. The ratio depends on roof geometry. An inspector measures the net free vent area and compares it to code. Quebec's climate demands more ventilation than milder regions. Ventilation des toitures en tuiles en automne explains the seasonal adjustments in detail.
Tile installation quality also matters. Tiles must interlock tightly. Loose or cracked tiles let water in. The underlayment must lap correctly at eaves and valleys. Flashing around chimneys, skylights, and vents must be sealed. An RBQ inspector checks all of these. Comment la pose de tuiles par un couvreur certifié RBQ prévient les barrages de glace covers the installation standards that prevent ice dams from the start.
Thermal mass is another factor. Tile roofs absorb and release heat slowly. That can keep the roof surface warmer at night. In some conditions, that warmth helps melt snow evenly. But it can also work against you if the attic is poorly insulated. Heat from below combines with solar gain to create uneven melting. How tile roofing's thermal mass mitigates ice damming examines this balance in Quebec's thunderstorm season.
Structural risks go beyond ice damming. The viaduct collapse was a reminder that hidden deterioration can be catastrophic. On a roof, that means checking the deck for deflection, the rafters for cracks, and the connections for corrosion. An RBQ inspector will look for signs of past leaks, such as stains on the underside of the deck. They will also check that the roof can carry the expected snow load. Quebec's building code specifies minimum snow loads by region. A tile roof is heavy. Adding ice and snow can push the total load past safe limits.
Outcome
After a certified inspection, you get a written report. The report lists deficiencies in order of severity. It tells you what to fix now and what to monitor. It also gives you a baseline for future inspections. That baseline is valuable. It lets you track changes over time. If a small crack appears in a rafter, you will know it is new. If the ventilation was adequate last year but not this year, you can find out why.
Published research on tile roof performance in cold climates shows that ice damming is a leading cause of premature roof failure. Something like 30-50% of roof leaks in Quebec winters trace back to ice dams. That is a 2 of 3 on evidence quality, because most studies are observational. But the pattern is consistent. Roofs with poor ventilation and missing underlayment fail first. Roofs with regular inspections last longer.
Extreme weather is becoming more common. A recent survey found that 7 in 10 Canadians are concerned about extreme weather, floods, and tornadoes, as reported by GlobeNewswire. That concern should extend to the roof over your head. A tile roof that survived last winter may not survive the next one. The viaduct collapse was a failure of inspection and maintenance. Your roof does not have to follow that path.
One more point about asphalt shingles. Many Quebec homes have them. They are lighter than tile and cheaper to install. But they do not last as long. When an asphalt shingle roof fails, it often fails suddenly. A tile roof gives more warning. That warning only works if someone is looking. An RBQ-certified inspection is that someone.
The cost of an inspection is small compared to the cost of a new roof. It is also small compared to the cost of water damage inside your home. If you have a tile roof, get it inspected before the first heavy snow. If you have an asphalt shingle roof, get it inspected too. The principles are the same. The risks are the same. The only difference is the material.