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Renovation & Design

MIKE HOLMES: Don't let your roof crack under pressure

Postmedia/Icicles on this home could have been prevented had the attic been properly ventilated.
Postmedia/A look through the thermal camera reveals areas with insufficient insulation that may lead to ice build up.

Whether it snows or not, we probably have about two and a half more months of this winter wonderland. Maybe three, depending on where you live. And even though Jack Frost was a slow starter this year, he always means business when he gets going.

Some people might think that a mild winter is easier on a home than extreme cold weather and lots of snow. But the truth is that both have their risks.

While deep-freezing weather can cause a homes pipes to freeze, and eventually burst, milder winters can be just as threatening to our homes. How? Because of the extra moisture in the atmosphere.

Deep-freezing weather is dry, because the cold sucks moisture right out of the air. But during a mild winter, theres usually a lot of precipitation -- and that sets up the conditions for freezing rain. And when freezing rain accumulates, it puts a lot of stress on your home, primarily, its roof.

For freezing-rain damage to occur, two things need to happen. First, we need precipitation, such as snow. And second, we need warmer, wetter air hitting cold air. When this happens, we have falling snow melting, then refreezing. But there isnt enough time for the precipitation to fully crystallize and turn into snow again. So instead, it instantly freezes when it hits an object. When that object is your roof, you need to be concerned.

Weve heard the horror stories of roofs and garages collapsing under the weight of ice and snow. Is it due to poor maintenance? Shoddy construction? Crappy materials? Actually, its usually caused by crappy weather.

Major ice storms cause extensive damage, even deaths, because the accumulated ice causes power lines and trees to snap, which leads to widespread power outages. People can be left without heat or power for days, even weeks.

And the lack of electricity isnt the only danger. In some storms, sheets of solid ice several centimetres thick can form on top of roofs. Many roofs just cant handle the weight.

Roofs most prone to collapse are flat rather than sloped. A sloped roof doesnt allow as much ice or snow to accumulate, and, to my mind, the steeper the slope, the better. Ice that forms on top of sloped roofs doesnt get as thick, and that which does accumulate does so around chimneys, skylights, and along the roofs edge.

The possibility of damage to your roof worsens when melting ice and snow arent allowed to drain. This is typically because of ice dams on the roof and frozen water in eavestroughs. Plus, pressure caused by ice on roof flashings can lead to roof leaks.

Whether or not your roof can stand up to the weight of winter also depends on the structure below it. If walls inside the home have been removed during a renovation, this may have compromised the entire structural integrity of the house, including its roof. That means the roof wont be able to sustain the regular weight it should be able to carry under regular conditions -- let alone the additional load of snow and ice.

The best way to get rid of ice and snow on a roof is by creating a proper draining system. Physically removing the ice by chipping it away is dangerous; those sliding slabs can knock you right off the roof, or worse, they can hurt and even kill you. And in most cases, doing so invalidates the warranty on the shingles.

Removing ice on your roof is not a DIY project, by any means. If ice needs to removed, you need to call in a professional who has a lot of experience dealing with this type of service and who has been properly trained to use the right equipment.

So how do you know if you need to call in a pro? By determining if the ice and snow on your roof is compromising the homes structural strength. Youll know this if the doors inside your home start to jam and if new cracks start to show up in the drywall and plaster. If you see these, you need to monitor them and make sure they arent getting larger and spreading. Finally, you also need to check your roofs ridge line. If it seems like its sagging, its time to call in a pro.

-- Postmedia News

Catch Mike in his new series, Holmes Inspection, airing Thursdays at 8 p.m. ET/PT on HGTV. For more information, visit www.hgtv.ca. For more information on home renovations, visit makeitright.ca.

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