Leaks and loose shingles are certainly annoyances, but one roofing malfunction stands out from the crowd in terms of severity: a total collapse. The most common cause of roof collapse is excessive snow accumulation, especially on a flat or gently sloped roof. If you live in an area that receives heavy snowfall, knowing how to prevent roof collapse, and how to detect the earliest signs that something is wrong, is vital.
It is hard to estimate exactly how much snow a roof can hold, since every roof is different. Many homes in New England are designed to withstand more weight from snow than homes built further south. The greater the slope of your roof, the less you have to worry, since snow will likely slide off as it continues to fall. If you have a flatter roof, however, you need to be more wary of heavy snowfall.
Your roofing company may have given you an "estimated holding weight" for your roof when it was installed. If you cannot find this information, you can call the company that installed your roof and ask if they can provide it for you. Most roofs can safely support about 20 pounds per square foot, but yours may be able to handle more. Twelve inches of fresh snow, 5 inches of packed snow, and 1 inch of ice each place about 5 pounds per square foot of pressure on your roof. Use these numbers to estimate the weight of the snow your roof is supporting, and ensure it does not exceed your roof's estimated holding weight.
Other Signs of Possible Collapse
If the estimated weight of the snow on your roof exceeds the amount your roof is supposedly able to hold, this is a sign you need to act quickly to prevent a roof collapse. There are several other signs of possible collapse that indicate you need to act quickly:
- Your doors and windows are becoming hard to open, due to increased pressure on the upper portions of the frames
- The exterior masonry of your home is developing cracks
- Your roof is leaking severely
- Sections of your interior ceiling have begun to sag
If you notice any of the signs above, or if you believe the weight of the snow on your roof exceeds the safe limit, you'll need to follow the instructions below to remove snow from your roof:
Removing Snow From Your Roof
If you live in a small to moderately-sized home, you can likely remove snow from the roof yourself by using a snow rake. Snow rakes are sold at many home and garden stores, and they look much like garden rakes, except they have much longer handles.
To rake snow from your roof, stand as far back from the edge of the roof as you can, while still being able to reach up onto the roof. Place the rake down close to the peak of the roof, and then pull it back towards you. Watch for falling snow and icicles, and be careful not to hit any power lines.
If your home is very large or tall, you may not be able to reach all of the roof to remove the snow. Many roofing companies offer this service. Fees are generally reasonable, since it does not take an experienced crew long to remove snow from a roof.
Other Ways to Prevent Roof Collapse
In addition to raking excess snow off of your roof, you can also help reduce your risk of roof collapse by keeping your roof properly maintained. This includes:
- Having your gutters cleaned regularly, so melting snow drains through them rather than accumulating as heavy ice on your roof.
- Treating problems like loose shingles as soon as they develop.
A roof collapse can be a terrible tragedy, especially if you or a loved one are in the home when the roof collapses. Be proactive in preventing roof collapses by removing snow when it begins to approach your roof's estimated holding weight, and by keeping your roof in generally good shape. If you have an older roof, know the signs of an increased risk of collapse, and get roof repairs done before they have a chance to weaken your roof further. Leave your home for a safe place if you ever have concerns that your roof may cave in.