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-   -   Need advice on roof heat tape. (http://www.diychatroom.com/f18/need-advice-roof-heat-tape-24526/)

marchboom 07-31-2008 09:20 AM

Need advice on roof heat tape.
 
Having large amounts of snow and ice on my roof last year I have decided that I need to install heat tape in the rain gutters. Heat tape companies state that you should run the tape in the gutters and in a zig-zag pattern along the eaves but that adds up to a LOT of tape and a much higher electric bill. I have 330 feet of gutters. I have spoken to several electricians and rain gutter folks and they say that all I need is to run the tape in the gutter as that is what needs to be kept free of ice. The house is new and has plenty of blown in insulation and plenty of attic ventilation.

Has anyone used this tape and if so, what has been your experience with it. Should I run the zig-zag pattern?

Thanks

jrclen 07-31-2008 12:46 PM

There are two separate possible problems with the ice.

One is an ice dam at the edge and first foot or two of the roof. This is caused by snow melting and running down the slightly heated roof. The water then hits the area of the roof which is over the eves and has no heat. That water then freezes and forms a dam that more melt water can't get passed. The zig zag heat coils are laid on the roof for that problem.

Another, unrelated problem is the water freezing in the gutter itself. A straight line of heat tape laying in the gutter and down spouts would solve that problem.

So the answer depends on which problem you actually experience.

marchboom 08-01-2008 01:35 AM

I actually had both problems. We got snow which filled the gutter and it started to melt. Before it melted completely, it froze again and it stayed cold after that. Then we got snow that built up over the "block" of ice now in the gutter.

I could be wrong (I was once) but I think that as long as I keep the ice from forming in the gutter, I will be OK. Am I addressing this the right way?

jrclen 08-01-2008 08:50 AM

I would go ahead and try the tape in the gutter and see if that takes care of the problem. This past winter was bad around here, with people having ice dam problems that didn't have problems in other years. We even lost some roofs on farm buildings and garages from the weight of the snow and ice.

warmsmeallup 08-01-2008 03:35 PM

The right product to use is called Self-Regulating Heat Cable. "Self Regulating" means that the cable will get warmer, the colder it is outside. That saves energy when it's 30 degrees as compared to when it's 10 degrees. The stuff at the box stores is just a one temp element that goes to it's maximum temperature no matter what the outside temperature is.

The zig zag pattern that someone reffered you to is what you would do with the cable when applying it to your roof. When you are installing it in your gutters and downspouts the best application is a double run. The cable will melt any snow or ice that is in contact with it and (generally) within 1" around it. If you have a heavy snow fall, it will igloo in the gutter and then re-freeze over the top. So, a double run will keep the gutter clear. You do the same thing down the downspout.

If you have 330 linear feet of gutter, you probably have 8-10 downspouts. They need to be heated as well or it will just refreeze in the downspout and you won't be solving the problem. As a less expensive way to approach the problem, you could only treat the areas that get no sun and work from there.

Next is the controls.

I should say that this is our experience with gutter melt systems and experience dictates that we won't install them any other way.

Ash 08-01-2008 04:11 PM

It looks like huge waste of electricity. I'd just construct something so that the snow would trip down on its own

Consider the possibility of blackout or fault in the heat cable too

jrclen 08-01-2008 04:20 PM

Quote:

Originally Posted by warmsmeallup (Post 144929)
The right product to use is called Self-Regulating Heat Cable. "Self Regulating" means that the cable will get warmer, the colder it is outside. That saves energy when it's 30 degrees as compared to when it's 10 degrees. The stuff at the box stores is just a one temp element that goes to it's maximum temperature no matter what the outside temperature is.

Ahhh, an expert weighs in. Good thing. :thumbup:

warmsmeallup 08-01-2008 04:47 PM

Quote:

Originally Posted by Ash (Post 144938)
It looks like huge waste of electricity. I'd just construct something so that the snow would trip down on its own

Consider the possibility of blackout or fault in the heat cable too

"Huge" is subjective when the ice damage to the roof and outside walls costs more to repair (year, after year, after year until your insurance company says no more) than the installation of the system itself.

Yes, one of the downsides of exposed cable is the possibilty of damage in ice or snow slides. It's not really an issue in the gutters unless you use a chain saw to clean your gutters. It's the "on-the-roof" application that has the higher risk.

But, then there's Zmesh to the rescue! :whistling2:

Ash 08-01-2008 05:22 PM

I mean a solution like allowing snow to slide down and fall on its own

For example if the rain sink is stopping the snow it can be removed (just let the rain drip off the end of the roof naturally)

warmsmeallup 08-01-2008 06:32 PM

Quote:

Originally Posted by Ash (Post 144956)
I mean a solution like allowing snow to slide down and fall on its own

For example if the rain sink is stopping the snow it can be removed (just let the rain drip off the end of the roof naturally)

That's not how it works. The escaping heat from the building melts the snow, the water runs down the roof to the overhang (where it's no longer being heated) and then refreezes both in the gutters and on the roof. Especially on north facing sides. The ice builds and builds until it works its way back up the roof to the melted area and literally lifts the covering (shingles, metal, whatever) and then the heat from the exterior wall remelts it and it runs down the inside walls destroying everything on the way down. If you have the batting type of insulation, it becomes a sponge and holds the water in your walls becoming mold. Need we go further?!

The gutter "helmets" that keep the leaves from clogging the gutters in the summer and fall are nothing more than industrial ice makers in winter. They neglect to inform you about this little aspect of their design. Great for the southern states...a danger in the northern states.

jrclen 08-01-2008 07:43 PM

Quote:

Originally Posted by Ash (Post 144956)
I mean a solution like allowing snow to slide down and fall on its own

For example if the rain sink is stopping the snow it can be removed (just let the rain drip off the end of the roof naturally)

No offense Ash, but which southern, non snow, state are you from? :laughing:

marchboom 08-02-2008 09:46 AM

I wish the snow would just slide off the roof but we have an asphalt shingle roof with a 7/12 pitch. No sliding here. I was hoping that we could get away with just heat tape in the gutter...and maybe we can. That was the problem last year. The gutter became a big block of ice and it built up from there. But then we had near record snow fall too.

Looking around at the other homes in the area and no one has heat tape on their roof. I'm just wondering if they only put it in their gutters and that is all that's needed?

jbfan 08-02-2008 04:02 PM

Quote:

Originally Posted by jrclen (Post 145027)
No offense Ash, but which southern, non snow, state are you from? :laughing:

Snow? What is snow. That is something we get when the stores want to empty all their shelves. When they predict snow, all the milk, bread, and peanut butter disappers.

Snow is what happens up north when my ac is still running.
Ya'll enjoy the snow!

warmsmeallup 08-02-2008 04:04 PM

Quote:

Originally Posted by marchboom (Post 145150)
Looking around at the other homes in the area and no one has heat tape on their roof. I'm just wondering if they only put it in their gutters and that is all that's needed?

Actually, I would recommend that you do just the gutters and downspouts to start with and see if that solves the problem. Doing them now will not effect the cost of doing the roof area next year one way or the other.

fungku 08-02-2008 04:12 PM

Also, for future reference, it is typically a good thing to follow manufacturer's directions. For insurance and warranty purposes.


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