What are the advantages of a Cold Roof System?

Snow slipping during Juno blizzard 2015

This house is in for trouble! That snow is going to slip off and crush something below it.

A COLD Roof During One of the Worst Blizzards in Years?  Yes!

As I write this blog on January 27, 2015, 8000 airline flights have been cancelled, more than 35,000 customers are without power in Connecticut and Massachusetts, including all of Nantucket, the Pilgrim Nuclear Plant in Massachusetts has been shut down temporarily and Framingham, Massachusetts, is the first town to report at least 30 inches of snowfall from Juno, the biggest blizzard to hit New England in years.

It’s a great time to talk about a Cold Roof System for your house.  No, I am not crazy to promote this idea of a system that is COLD during such a COLD period.  There is a very good reason to consider it.  Let me explain why.

Cold Roofs stop ice dams!

Ice dams cause leaks!

Who wants leaks and damage to your roof or your property caused by a big blizzard (or a little one, for that matter)?

Cold Roofs help prevent leaks caused by snow and ice build-up.  As that snow melts in the coming days you certainly don’t want a leak and many of you are headed for that.

If your house is warm on the inside, and I certainly hope it is (some of our New England friends haven’t seen 10 degrees for more than a week), that heat is rising and going straight up into the attic.  What happens once it gets there?

Simply put, the heat in your attic warms up that snow on your roof, causing it to melt.  That melted snow, in the form of water, runs down underneath the huge pile of snow on your roof straight down to the eave.  The eave is NOT warm, so that water freezes again and can cause a dam of ice, stopping the melt water that is running down and causing bigger and bigger ice dams which create another dam behind the original ice dam.

Ice dams are BAD.  They can make the continually melting snow, now in the form of water, back up and run down into your wall.  The ice dams can also break lose when you close your door one day and fall on your head.  You don’t want ice dams.

So, the best way to stop this kind of damage is to create a cold roof.  Cold roofs  are designed using three main factors – adequate insulation, ventilation under the roofing materials and maintaining snow in place.

Insulation is a key factor in a cold roof system.  It should be installed under the cold roof either in the rafters or the ceiling joists.

Proper ventilation is critical.  You can’t just put a screen down at the eave and a few vents in the roof and expect the roof to become cold enough to stop ice damming.  However, it’s also not that hard to get proper draw from the eave to the ridge. cold roof venting diagramTRA Snow and Sun can engineer the system for you when we design your snow retention.  We take into account the roof design (hip, straight gable, etc.) slope of the roof and length of roof from eave to ridge; all important factors when creating a cold system.

Which leads me to roof snow retention.  Snow does not slide off roofs in a controlled fashion.  It can be incredibly unpredictable and can cause ponding in low slope roofs with increased chance of leaks, can slide off and damage gutters, sidewalks, shrubbery and hit people.  Ponding of heavy snow is a contributing factor in many roof collapses.  And contrary to popular opinion, buildings constructed in the last 3 decades had to be built to withstand heavy snowloads, so shoveling snow off is probably not worth the risk of hurting yourself doing it.

A true cold roof system will keep snow in place, allowing it to melt naturally, provide an insulative blanket on the roof and help prevent uneven build-up and its associated heavy weight which can lead to roof collapse.

So, stay bundled up in your warm house and wait for the storm to pass, but once you can get outside, take a look at those ice dams and then call us!

Terry Anderson, president of TRA Snow and Sun, and an expert in Cold Roof systems, co-authored a book on cold roofs.  Check it out here.