Winters in Bucks and Montgomery counties typically bring plenty of cold weather and significant amounts of snow. Even residents who appreciate living in an area with four distinct seasons are not always excited about the harshest winter weather.
The two to three feet of snowfall the area normally receives each year can, in fact, cause real problems for homeowners. When snow and ice build up on residential roofs, damage can result through any of several mechanisms. Being familiar with the most important issues will equip you to take any action that might be needed to protect your own home.
The Weight of Snow and Ice Can Cause Damage to a Roof
Pure ice weighs nearly sixty pounds per cubic foot. While that is a bit less dense than liquid water, a residential roof covered in solid ice can end up bearing thousands of pounds more than usual.
Snow weighs less than a similar volume of ice, with its crystalline structure trapping essentially weightless air within it. Even the fluffiest of freshly fallen snow, though, will become denser over time as it settles, compacts, or refreezes after partially thawing.
Well before winter comes to an end, that can leave a home’s roof struggling to withstand the burden imposed by accumulated snow and ice. In the worst of cases, excess weight can cause so much damage that an entire roof will collapse. More often, heavy accumulations of snow and ice leave roofs structurally intact but plagued with problems like leaks or sagging.
The Insurance Institute for Business and Home Safety estimates that the average residential roof in good condition can support about twenty pounds of snow per square foot of surface area. A square foot of fresh snow twelve inches deep will normally weigh about five pounds, with older, compacted snow often being two to three times as dense.
Should an unusually strong winter storm drop several feet of snow on your roof or more, it will therefore be wise to arrange to have it removed. A roof that accumulates two or more feet of older, packed snow before spring arrives could also require attention.
Careful, ambitious homeowners in the area sometimes use special, extensible rakes to pull snow from overburdened roofs. A safer option is to have a professional remove snow and ice when they accumulate to the point of posing a problem.
Ice Dams are an Even More Pointed Threat
An even more serious threat to many homes results when snow on a roof melts but fails to drain away before refreezing and turning into solid ice. This most often happens when warm air rising up through a home heats parts of a roof above the freezing point but leaves the edges below it.
Melted snow that freezes solid along the edges of a roof can form an icy dam. With this solid structure making it even harder for water to escape, many gallons of water can accumulate on the surface of a roof.
The mere weight of all that liquid can stress a roof beyond the breaking point. Water that sits on the surface of a roof for days, weeks, or even months will also start causing other problems.
That most often means seeping under shingles and other parts of a roof and doing damage in the process. Moistened roofing materials that subsequently freeze and thaw can also be destroyed because of the expansion and contraction they experience. If an ice dam is allowed to stand for too long, the moisture that seeps down into a home can destroy other building materials and allow mold and mildew to develop.
Unfortunately, ice dams can be difficult to detect, since the problematic developments sometimes happen underneath an innocent-looking layer of snow. Because the problems they cause can be so serious, it will always be best to try to prevent the formation of ice dams entirely. Some of the tactics that help are:
- Keeping drainage systems clear. When gutters or downspouts get clogged with debris or even ice, melted snow becomes more likely to form ice dams at the edge of a roof. Making sure that gutters get cleaned before winter arrives will help keep the threat to a minimum.
- Doing away with hot spots. Unwanted melting of roof-borne snow on cold days most often results from an attic that is unevenly heated. A bit of missing insulation can allow too much of the heat within a home to conduct to the outside of a roof. Even a ceiling-mounted light fixture in an attic can warm the roof above to the point that accumulated snow starts melting.
- Improving roof ventilation. A properly ventilated roof should maintain a relatively even temperature across its exposed surface and from inside to outside. Improved roof ventilation that does away with the temperature differential that allows ice dams to form can rule the problem out entirely.
Certain Homeowners Have More to Keep in Mind
Excess weight and ice dams are the two roof-related wintertime dangers that most often trouble homeowners in the area. There are some other issues to be aware of in certain cases, though.
Flat residential roofs generally include drains intended to make up for their lack of drainage-inducing slope, for instance. Should a flat roof’s drainage system freeze up or otherwise become clogged, the entire structure will become more susceptible to the formation of ice dams and the damage caused by excess weight.
Roof-based features like skylights can easily leave a roof more vulnerable to the problems snow and ice sometimes cause. Even failing to note the presence of a skylight can lead to trouble when having a professional clear snow from a roof.
Effective Help is Just a Quick Call Away
While people in certain other parts of the country have much more to worry about, snow and ice can impact roofs in eastern Pennsylvania quite significantly. Homeowners who are informed about the dangers and related issues will always be better positioned than others to take appropriate action.
Give Dennis and Sons Roofing a call to learn more about some of the available solutions or any other roofing-, siding-, or window-related matter. Your home’s roof is one of its most important assets, so keeping it safe and strong through winter and beyond should always be a top priority.