How do I prepare my garage roof for the heavy wet snow that Ottawa gets in March?

March snow in Ottawa is genuinely brutal on garage roofs — it is dense, wet, and heavy in a way that January's dry powder simply is not. The good news is that most properly built garages can handle it, but there are smart steps you can take to reduce stress on the structure and avoid the kind of ice dam and drainage problems that March's freeze-thaw cycles create.

The first thing to do is clear accumulated snow from your roof before a major melt-refreeze event. A roof rake — the long-handled tool with a flat blade — lets you pull snow off the lower edge of the roof from the ground without climbing a ladder. You do not need to clear every centimetre; removing the bottom two to three feet of snow from the eaves is the most important move, because that is where ice dams form. Ice dams happen when heat escaping through the roof melts snow higher up, the meltwater runs down to the cold eave, and refreezes into a ridge of ice that traps more water behind it. That trapped water finds its way under shingles and into your structure.

Check your eavestroughs and downspouts now, before the March melt hits. Pull out any debris that accumulated over winter — leaves, ice chunks, and granules from aging shingles all clog gutters and prevent meltwater from draining properly. A clogged eavestrough in March fills with ice and can pull away from the fascia under its own weight, which is an expensive repair. Make sure your downspouts are directing water away from the garage foundation, not pooling against it — March meltwater is one of the main culprits behind foundation moisture problems.

Inside the garage, take a look at your ceiling for any signs of water staining, soft spots in the drywall, or visible daylight around the peak. These are early warnings of roof penetration or inadequate insulation allowing ice dams to form. If your garage ceiling is insulated to at least R-32 and you have proper soffit and ridge ventilation, your roof deck stays cold enough that snow melts evenly rather than in the problematic patches that create ice dams.

If you have a flat or low-slope garage roof, March deserves extra attention. These roofs are more vulnerable to ponding water as snow melts, and any small crack or failed seam in the membrane becomes a leak point. Walk the roof carefully if it is safe to do so, and look for blistering, cracking, or areas where the membrane has separated from the parapet or flashing. A roofing contractor can apply a cold-weather sealant to small problem areas before the main melt arrives.

One honest warning: if your garage roof structure feels soft, bouncy, or shows visible sagging, do not wait. That is a structural concern that needs a professional assessment before the next heavy load event. The 1998 ice storm taught Ottawa homeowners that roof failures happen fast and without much warning when the load exceeds what the structure was designed to carry.