Heritage Restoration, Inc.

Roof Melt Systems

Would you have information on heating wires for the roof?  We had a very bad winter with ice dams and water damage on ceilings.  We would like to have them installed this spring because we don’t want to have this happen again.  Just had a brand new roof and gutter helmets put on but it didn’t stop the ice dams.  Could you recommend the best heat wiring system to put on?  Any information you can give will be greatly appreciated.  Thank you in advance.


Jim & Marilyn


A roof heating system prevents snow accumulation and ice from forming by keeping the roof warmer than freezing.  The column “Pay attention to Your House, It Needs You More Than Ever” a month ago left out roof heating systems as a method to resolve ice damming for a good reason.  Making your roof warm is a solution to prevent a problem, but not a solution to fix the problem.  The problem is your house is making the roof warm.  The best installed roof will have ice damming if the house is not air sealed and insulated correctly.  But we are in the reality of life and house maintenance, so we need solutions to problems, not someone preaching perfection.


Prevention Is Key

A properly built house & roof (as opposed to design, since many are designed well but built wrong) will prevent ice damming.  A roof should either breath, (Cold Roof), or be a part of a mass (Hot Roof).  Either method requires air sealing first, to prevent warm air from melting snow and making ice.  The cold roof design is best, where there is a space between insulation and the bottom of the roof sheathing.  The space can be as little as a few inches so cold air keeps the roof cold, or where the floor of the attic is insulated.   A hot roof is where entire roof system is one, using spray foam to thicken the mass of roof and separate it from the warm house.   While proper air sealing and insulation is the most cost effective and energy efficient, it may not be either financially or physically possible, so melting the snow and ice on the roof is the next best solution.


The Under Fix

There are electric mat warming systems that can be installed under the roof shingles.  The systems are like radiant floor heating systems, where the entire roof plane is heated.  This system should be coupled with a gutter de-icing system, so melting snow and ice do not refreeze in the gutter.  There is a danger of poor installation, where some systems may be compromised or dangerous by piercing with metal, or proximity to conductive materials, like flashing.


The Over Fix

There are basically two types of systems that are installed on top of the roof, electric and hydronic (fluid in tubes), with the most common system being electric.  These systems are fairly simple to install, using clips to attach to shingles or nailing into the roof (although never, EVER, nail through your roof, it breaks the seal).  The system is installed over the roof, as well as inside the gutters and downspouts.  How far up the roof depends on the depth of your overhang.  Most systems have conversion charts to determine the quantity of material you need.  Most systems are sold by the foot or in rolls.


Did I Turn It On?

The trouble with a switch is remembering to turn it on or off.  Many of the less expensive systems rely on manual activation, requiring the user to know when it should be on or when to turn it off.  Timing is everything, and forgetting to turn it on or being away on a trip can make the whole system moot.


There are manual timer activations or more intricate designs using automatic sensor that activate/deactivate the system when the temperatures drops below 38 degrees and it is wet.  When either the temperatures rise or the wet weather clears, the sensor will automatically shut the system off.


So ice damming prevention is best by properly air sealing and insulating.  If that is not an option, roof heating systems can be inexpensive and easy to install.  But like everything else fast and cheap, it is a temporary solution to a bigger problem.  The only other solution is a warm winter, which is a whole other controversy.

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