The Importance of Keeping Home Ventilation Clear of Snow

December 8, 2024 - DMC Residential Inspection Services Inc.

As the Owner and Inspector at DMC Residential Inspection Services, I recently conducted a home inspection that highlighted the danger a significant amount of snow can bring to homes and occupants. During the inspection, I observed the roof vents and plumbing drain vents were entirely buried under snow. Also, although not yet covered, the furnace gas vent and main gas shutoff valve was on its way to being covered if a little more snow were to be received. As many of us living in the South-Western Ontario Snow Belt Region are aware, significant amounts of snow can accumulate in a short time period bringing with it a unique set of challenges for homeowners to ensure ventilation remains unobstructed and accessibility to essential utilities is maintained. Keeping ventilation and key utility systems free of snow cover and accessible during winter is critical to safeguarding your home and family.

Home ventilation systems are designed to regulate air quality, expel harmful gases, and ensure the safe operation of combustion heating systems. Some of the main components affected by snow accumulation can be roof vents, gas furnace and gas hot water heater vents as well as gas shut off valves.

When roof vents are plugged with snow, air is not circulating in the attic and can potentially lead to moisture buildup, mold growth and wood rot. Heat can build up in the attic enough to melt the snow on the roof creating ice dams that damage roofing and gutters and lead to water leaks. When gas vents are plugged, CO2, and other harmful gasses produced during combustion, can back up into the home creating a severe health hazard. Also, depending on the safety features of your furnace, it could result in shutting down leading to the home being without heat in freezing temperatures.

The gas supply shut-off valve is a key component of the home’s gas system. It is important to ensure it is accessible at all times in case you need to quickly shut off the gas supply to the home. In an emergency, such as a gas leak, the ability to quickly access and shut off the gas supply can help prevent more extreme issues from developing.

During the inspection, I was amazed by the amount of snow that had accumulated on and around the home’s essential ventilation components. Drifting and prevailing winds had deposited much more snow on the rear of the home’s roof than on the front. The roof and plumbing drain vents were completely hidden under several inches of snow, effectively blocking air circulation to the attic and plumbing system. If a little bit more snow was to accumulate you could see how easily the furnace vent could become entirely covered, resulting in concerns about CO2 buildup. The main gas shutoff valve, is located close to the ground near the home’s exterior and was on its way to being buried under a snowdrift making it difficult to locate quickly in an emergency.

It is important for homeowners to take proactive steps in understanding and preventing these problems from occurring to help ensure protection for the home and safety for the occupants. In winter months it is important to stay vigilant on snow accumulation being sure to clear roof vents, check for ice dams, ensure gas vents and gas shutoff valves remain unobstructed and accessible. And, as always, ensure smoke and CO2 detection capability is in place and working properly.

The issues I encountered during this inspection underscore the importance of regular home maintenance and inspections, especially during winter months. In the winter months homeowners need to remain vigilant of the dangers snow accumulation may have on their home. Identifying these potential hazard areas and ensuring snow accumulation is kept at bay around key components will help to ensure the safety of the home and occupants.