Aluminum Ice Dam Preventers

10/10/2011 at 8:35:35 PM

Hi Gayle, I think I understand what you are talking about. They are little metal pieces that stick up from a metal roof in a staggered pattern near the eves. They are generally used only on metal roofs to prevent a single large sheet of snow from sliding off all at once. You are correct that their purpose is to break the sheet up into little chunks so nobody gets injured. All of the Home Depot stores in the GTA have had them retrofitted over the entrances and public areas. This situation is not an ice dam, it is just the nature of a sloped metal roof - it acts like a slide for snow when a little water trickles down underneath it as there is no "texture" to hold the snow as there would be on a shingle roof. You can Google "snow guards for metal roofs" and get a bunch of sites with info to pass to your roofers. If you actually do have ice dams, that is an air movement problem - could be not enough insulation or vapour barrier issues in your attic or not enough air flow from the soffit to the peak - or both. The first allows warm air from your house into the attic area and causes the snow to melt from below. When it gets really cold, the water running down actually freezes instead of running into your eves trough and away from your roof. The freezing is what causes the ice dam and will then cause water to back up under the shingles and through your roof deck. The second keeps the roof cold and does not allow the snow to melt. You really need to have both conditions looked at and corrected if needed.

You should post your project on the site and I am sure many contractors will contact you.

If this does not describe the actual conditions you have, please post a little more info for us to look at.

Good Luck,

Jim Kuzma

Kettleby Handyman Services

PS - let us know how it went.