Why is ice forming along siding from roof?

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Posted by: from Timmins
12/29/2014 at 2:59:33 PM

Our home is an A frame with side additions. We installed heat trace line along the A frame valley and along the edge of the additions to prevent ice dams. However, the snow is melting off the A frame, seeping through the soffit and facia and coming down the siding, where the additions meet the A frame; and turning to ice.

How can we prevent this from happening?

We also only keep the heat trace on an average of 3 to 4 hours a day. Should we leave it on longer?

Why is ice forming along siding from roof?
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Bob in Smiths Falls
Date/Time12/29/2014 at 7:09:26 PM


This is Bob Place from Bob Place General Repair.

Most of your problem is not enough insalation and or no ventalation!!!! You fix this and I promise it will go away.

Good luck.

Bob Place

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Mario in Timmins
Date/Time12/30/2014 at 9:01:45 AM

Hi Bob. Thank you for replying.

We put R 44 insulation on the roof and floor and R 22 on the walls of the additions. There are 2 vents on the addition roof as well. We don't have the problem if we don;t have the heat trace line on. However, if we don't use the heat trace line on the valley of the A frame, ice dams are a problem in the spring.

We've had a number of contractors tell us that the only way to remedy the A frame valley issue is to rebuild the whole A frame roof and extend it so air space can be created. We're not prepared to go through that!

Having said all that, do you think we should keep the heat trace on 24/7 all through the winter and put up with the ice along the siding until spring melts it? Should we only turn it on closer to spring when the ice will turn to water and just run off?

Will the ice on the siding melt and possibly make its way inside the house or will it just melt off the siding?

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Date/Time12/30/2014 at 6:09:53 PM

Hello, this is Tony from ontario home improvements. Looking at your picture and reading your issue the problem maybe with your heat trace it may work great for that 3 to 4 hour time frame you have it on but the problem is when you turn it off the problem is all the ice and snow that was melted during that small time the heat trace was on melted the snow inside the gutter only to have it freeze into solid ice not allowing it to drain. The heat trace should run along the gutter and the down spout to allow the water to run down and out.

You should extend the heat trace and leave it on a low setting.

Hope that helps.


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Mario in Timmins
Date/Time12/31/2014 at 9:16:34 AM

Thank you Tony, for your reply.

Your reply really made sense and indirectly, I think you may have provided the solution to our problem; although, we won't really know if it'll work until spring!

Because it is so cold here in Timmins, melted ice and snow never have a chance to run down and out of the gutter until spring. Therefore, the answer may be that we should only put the heat trace on closer to spring.

We don't have ice dam issues with the A frame until close to spring, when it's warm enough for thaws and refreezes. So, is it logic to only run the heat trace closer to spring?

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Date/Time1/11/2015 at 11:43:07 AM

Hi Mario,

Yes, I believe the best time to run the heat trace would be only during the spring in order to stop the cycle of thaw and freeze.

Good luck and hope I was able to help.

Thank you,


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