Fighting roof leaks on a flat roof can be a struggle. Even with the highest quality roof you are constantly in a battle against gravity. It’s not a question of if, but when gravity will win and water will find a way inside. Whenever a flat roof is hit by freezing rain, sleet, or a significant amount snow, the groundwork for a leak is there. Almost instantly, freezing rain will cover your roof in a sheet of ice. With a single day of sun exposure, loose sleet will become a solid block of ice. With a significant snowfall, the issue is due to the gradual melting of the snow were it touches the roof. If air temperatures are very cold, as the melted snow creeps towards the gutter, it will begin to freeze. If this occurs, as the snow continues to melt it will form a sheet of ice just like sleet and rain.
If temperatures don’t get high enough to quickly melt off the ice, over the days following the initial precipitation, the ice will slowly be melting from the bottom up due to the heat coming off the roof. If the air temperature is significantly below freezing when this happens, this newly thawed ice will refreeze in the gutter system. If enough of it accumulates, the entire gutter will fill with ice and begin to form a dam along the edge of the roof. Since this ice dam will block the ice melt’s access to the gutter system, the melting water now has nowhere to go. It is trapped between the ice and the roof. Over a long enough period of time, this trapped water will find a way to get through roof membrane and into your building.
So what can you do to fix this problem? Unfortunately, most of your options are preventative measures. Once the ice has formed, you are usually stuck with it until it melts on its own. Any attempt to break up the ice could actually end up damaging the roof as the ice is often stuck to the roofing material and any tools used to remove it could tear the roofing. The most important thing is to keep your roof in good condition. If the adhesive or tar on seams and around roof openings are in poor condition, the trapped water will find a quick and easy pathway inside your building. The better condition of the roof, the longer it can withstand the weight of the ice and the ice melt. The other important preventative measure is to make sure your gutters are clean. If leaves or other debris cause improper drainage, the damming will occur more quickly.
While such winter storms don’t happen often in most locations, not keeping up on maintenance can lead to a lot of troubles. Make sure you are prepared for the next storm.