Fighting ice dams

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Old 03-06-15, 08:27 AM
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Fighting ice dams

Every year when we get enough snow, I have a problem with ice dams and subsequent leaks in one particular spot. I must say that I can't reach that spot with a roof rake, nor can I go up on the roof myself. I'm attaching the picture. You can see that there are three separate parts of the roof from which water goes into that one trouble spot, right against the wall, and then it somehow seeps through the cedar siding. Also, I assume, the snow piles up right against that wall as well. I've been trying to figure out a permanent solution to this problem. A heating tape has been suggested, and also putting a gutter where it's obviously missing from the top roof. I'm not that convinced that heating tape will do the job.

I never have any problems with rain, only with melting snow when there are ice dams (and they always form in that corner).

I'd really appreciate any suggestions. Thank you.Name:  roof_cleaning2.jpg
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Old 03-06-15, 09:16 AM
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A builder in NY should know better than to create that collection point.
Heat tapes are a last resort.
If the roof gets redone, Ice and water shield should be generously applied, but that is not a solution, just added protection once the ice dams form.
The same for gutters, not a solution as they can and will get filled with ice and become part of the problem. Nice for rain, but not during ice conditions.

The real solution is to prevent the snow melt and thus prevent the ice dams right at the source. One limitation is that all snow melt doesn't originate from heat in the attics (some comes from the sunshine), but the bulk of it does.

The traditional approach is to seal all air leaks into all of those attic spaces as air transports heat as well as moisture. Then, you need lots of insulation to reduce the heat loss to the attic even further. Finally, you need great ventilation to keep the bottom of the roof deck cold.

If none of that is possible, we don't know what is inside that structure, then we will look for plan B.

Bud
 
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Old 03-06-15, 09:29 AM
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Yeah, unfortunately that collection point was created by the previous owner of the house with an addition when they turned an open deck into a sunroom. So, there is really no attic there, and I don't really know what kind of insulation they have there. Also, there is no easily accessible attic over the "middle" roof -- I have vaulted ceiling there.

The roof was redone about seven years ago. 8 feet of ice and water shield was applied, but I don't know exactly how well everything was done.
 
  #4  
Old 03-06-15, 09:41 AM
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That's what I was afraid of. You currently have heat loss from 3 roof surfaces plus that wall and getting all of them up to extreme insulation levels will be challenging.

Some of the more active contractors will be commenting, but some food for thought.
A 4" layer of rigid foam (maybe more) could be added to the roof assembly to protect the shingles from the heat below.

As for keeping the snow out of that collection point, you have probably seen those 2x4 ladders left in place on an old farmers roof, well that is one of the reasons they are up there. I have something similar where I just add my aluminum ladder in the winter and up I go. More to it, but that is a thought.

When additions are added by home owners they can often put things together that create mold as well as these ice issues. More investigating to determine structure depth and just how everything is air sealed and insulated needs to be on your list.

Bud
 
 

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