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Ice Damming On Roofs Can Cause Leaks

So, here in Hampton Roads we sure have seen some “different ” weather lately. The last snow left eight inches at my house and the very cold temperatures hung around for several days afterwards. I do not recall any storm like it around here in recent memory and I am not looking forward to anymore of it either. In fact, in 17 years of owning Andrews Roofing, I have not seen us this challenged with any weather event as far as scheduling work goes. We are missing many work days this winter because it has been either too cold or too “snowy” or “snow covered” to tear off a roof and put a new one on.

One roof problem this weather is causing more than usual is called “ice damming.” *See the graphic. Ice Dams_013114 This condition can cause some pretty serious leaks.

If your residential or commercial shingle, slate, shake, or tile roof eave overhangs your building in the form of a cornice , soffit, or “boxing” as some call it, you may especially be vulnerable to leaks caused by ice damming. This also happens in roof valleys.

All of your roof that is directly above heated space normally will thaw sooner than parts of the roof that are not. Yes, even though you have insulation in your attic, some heat escapes the living area and into the attic. The snow in this area melts before the snow lower down slope on the overhang eave, which is not above heated space. When the melted snow (water) runs down slope and hits that snow, it can’t escape because of the “ice dam” blocking it. The water backs up and causes leaks because these types of roofs shed water – the material is not water-tight like membrane roofs are. An added complication is when it stays below freezing for several days after snow and even until the next snow. Here we go again with more leaks.

There is a special roof underlayment material that we call ice and water shield. We put it in valleys and around all roof penetrations like chimneys and vents, etc. It provides added protection under the shingle roof in these crucial areas. Up north where snow occurs more often and is deeper, they use this underlayment on the eaves as well, and sometimes architects have us install it on eaves here. It helps to stop leaks caused by ice damming. The thing is that around here, its use on eaves is not very common because ice damming is just not that common of a problem.

If you need a roof soon, you may want to consider this. It will cost a little more, but the ice and water shield underlayment may help to avoid leaks caused by ice damming. The good news is that it may not snow like this again for several years so you may not leak again for several years because of this issue.

Call me with any questions about this or any other roof items. Thanks for reading.
P.S. A rain gutter at the eave can potentially cause ice damming too. Keeping your gutters clean may help.

Robert Andrews ll