# Uh-oh...rooftop ice dam damage. Dammit!

**URL:** <https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849>\
**Category:** Factual Questions\
**Created:** [February 2, 2011, 2:16am UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849 "2011-02-02T02:16:36Z")\
**Posts on this page:** 11\
**Page:** 2

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**Author:** ![Erdosain](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/erdosain/32/7284_2.png) [@Erdosain](https://boards.straightdope.com/u/Erdosain)\
**Post date:** [February 3, 2011, 12:09am UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/21 "2011-02-03T00:09:57Z")

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I had the same problem at my house this year. Water was coming through several windows and staining the ceiling in some rooms. I had some guys come and remove all the ice from the roof and the leakage stopped immediately. My homeowners insurance covered the ice removal and the projected repairs.

Unfortunately, it just snowed and the leaks have started up again. FML and FMRoof. With this weather it’s a pain getting any roofers to show up as they have a ton of work.

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**Author:** ![muldoonthief](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muldoonthief/32/3188_2.png) [@muldoonthief](https://boards.straightdope.com/u/muldoonthief)\
**Post date:** [February 3, 2011, 2:45pm UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/22 "2011-02-03T14:45:56Z")

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> [@sitchensis](#):
>
> I just want to point out that you can indeed use the heating cables after the fact.
> 
> Yes the heating cables come with clips to hold them to your shingles and those clips can only be used when the roof is not covered in ice, but in this situation just press the cable down into the snow and plug it in. The heat will cut trenches into the ice and gravity will carry the cable down to the roof.
> 
> By not using the clips the cable might fall off your roof in the spring, or it might look a little ugly compared to the pictures on the box, but for now it will do its job and if it can turn a two thousand dollar repair into a two hundred dollar repair it will be worth it.

From the product [Owner’s Manual](http://www.easyheat.com/Content1/PDF_Files/_files/11629_001_r2_ADKS_ownersman_web.pdf):

> [@](#):
>
> The deicing cable may be installed when:  
> • There is no ice or snow on the roof  
> Do not use this cable to melt snow and ice that has already formed on  
> your roof or in your gutters or downspouts, as you would not be able  
> to attach the cable properly with the clips. Additionally, this cable was  
> not designed to melt snow; rather, it simply provides a path for snow  
> or ice that has already melted (meltwater) to flow to the ground.  
> To solve ice dam problems when snow and ice are on the roof,  
> contact a professional roofer for expert advice.  
> To prevent future ice dams, you can install the deicing cable once  
> the ice and snow have melted and before the next winter season.

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**Author:** ![emmaliminal](https://avatars.discourse-cdn.com/v4/letter/e/7bcc69/32.png) [@emmaliminal](https://boards.straightdope.com/u/emmaliminal)\
**Post date:** [February 4, 2011, 2:57am UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/23 "2011-02-04T02:57:57Z")

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> [@salinqmind](#):
>
> T… some guy who was holding what looked like salt or de-icer formed into cubes. The idea being to pitch them up on the roof…

I’ve seen hockey-puck shaped ones around here, called [Roof Melts](http://www.roofmelt.com/). \<- **WARNING** : That link auto-starts a commercial video for the things.

I did not know that some people try laying melt cables on existing snow or ice and can’t speak to how well it works. Seems to me that if you plug them in to a GFCI outlet, what you mostly risk is damage to the cable, so it might be worth a try – but I’d want to check in with someone who knows electrician stuff first.

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**Author:** ![Pai325](https://avatars.discourse-cdn.com/v4/letter/p/c68b51/32.png) [@Pai325](https://boards.straightdope.com/u/Pai325)\
**Post date:** [February 4, 2011, 3:52am UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/24 "2011-02-04T03:52:02Z")

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My first experience with ice dams was about 2:30 this afternoon when the water started dripping in 3 places. Neither my husband nor I can get on the roof. I will try the panty-hose and ice melt tomorrow, but this year we have icicles all around the house. Someone is coming over tomorrow to see what he can do, but I foresee a long winter. Maybe once the ice melts and we go back to just snow it will be better. I guess I will have a roofer come in and look at everything this spring. I’ve never had this before. Are cables for next year a solution or just a band-aid on a cut?

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [February 4, 2011, 4:02am UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/25 "2011-02-04T04:02:34Z")

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best prevention is to heavily insulate your attic (above ceiling not under the roof deck) to loose less heat out roof, this also saves you in heating costs and cooling costs. also ventilate your attic space to keep it cold, this also helps in saving summer cooling costs.

the cables keep liquid melt water (caused by heat from your house through roof above attic) from freezing as it goes over the cooler roof overhang.

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**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\
**Post date:** [February 4, 2011, 11:39am UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/26 "2011-02-04T11:39:07Z")

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> [@emmaliminal](#):
>
> I’ve seen hockey-puck shaped ones around here, called [Roof Melts](http://www.roofmelt.com/). \<- **WARNING** : That link auto-starts a commercial video for the things.

I saw a story on the news last night where people are filling nylon stockings (panty hose) with ordinary calcium chloride ice melt, then chucking them up on the roof. They claimed that worked pretty welll, and the ice dams were broken in a couple of days.

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [February 4, 2011, 1:34pm UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/27 "2011-02-04T13:34:49Z")

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if you use salt on your roof then you should water the area a lot after the thaw and try to dilute the salt which is bad for any vegetation and soil it lands on.

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**Author:** ![Don\_t\_Call\_Me\_Shirley](https://avatars.discourse-cdn.com/v4/letter/d/f4b2a3/32.png) [@Don\_t\_Call\_Me\_Shirley](https://boards.straightdope.com/u/Don_t_Call_Me_Shirley)\
**Post date:** [February 4, 2011, 4:18pm UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/28 "2011-02-04T16:18:44Z")

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After unprecedented ice storms, I have an ice rink on a portion of my roof. Solid ice at least 2-3 inches thick. I also have some icicles coming out of one vent on my eaves, which seems like pretty good evidence that water is getting into the attic. The ground is also covered with 3-4" of solid ice, making a ladder ascent impossible. I tried putting some ice melt in a stocking but it just slid off the roof.

I have never had this problem before, so I hope it’s not insufficient insulation in my attic. It only happened on the part of the roof that is always in shade; other parts of the roof that get more sun don’t have any ice buildup.

How much insulation should I have in the attic? There is insulation blown in up there maybe 3-4" deep. I was thinking of putting a thermometer in the attic to see if it is getting too warm. What should the temperature difference between the house/attic/outside be? How much would it cost to get more insulation blown into a two-story, 2000 square foot house?

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**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\
**Post date:** [February 4, 2011, 4:45pm UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/29 "2011-02-04T16:45:52Z")

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> [@Don\_t\_Call\_Me\_Shirley](#):
>
> How much insulation should I have in the attic? There is insulation blown in up there maybe 3-4" deep. I was thinking of putting a thermometer in the attic to see if it is getting too warm. What should the temperature difference between the house/attic/outside be? How much would it cost to get more insulation blown into a two-story, 2000 square foot house?

for some values in USA

[http://www.ornl.gov/sci/roofs+walls/insulation/ins\_16.html](http://www.ornl.gov/sci/roofs+walls/insulation/ins_16.html)

having high R values (maybe 36 to 50) might be desired for a heating climate.

you would like the roof surface to stay below freezing (both insulation and attic ventilation produce this) providing it is below freezing outside. on a sunny day the roof will heat up and you want that heat to be only from the sun and not leaked from your house.

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**Author:** ![AshenLady](https://avatars.discourse-cdn.com/v4/letter/a/94ad74/32.png) [@AshenLady](https://boards.straightdope.com/u/AshenLady)\
**Post date:** [February 4, 2011, 4:47pm UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/30 "2011-02-04T16:47:57Z")

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> [@salinqmind](#):
>
> so…this is a first. Never had really big icicles dripping from the gutter until this year. And then the dripping was…yellowish. Brownish. And now - inside - there’s a little bit of water dripping from the ceiling, down the wall.
> 
> I am assuming water from ice and snow got under the roof shingles because I didn’t have the foresight to climb up a ladder onto the roof with a snow hoe and clean off the roof.
> 
> I am assuming I am fucked. Battening down the hatches here for another snowstorm, but when it’s all over in a couple of months - well, what then? Call the insurance company ? Call a roofer? Is the damage going to cost as much as the house is worth, or is it manageable? Will I need a whole new roof?
> 
> Because this NEVER happened to my house before. Just wondering if anyone wanted to share their ice-dam roof damage experiences.

We had the same thing from last year and needed a whole new roof a few months ago. Don’t let it go, once water is coming into your house, you can have all kinds of water damage and we will need to re-dry wall our entry way and kitchen sometime sooner or later.

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**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\
**Post date:** [February 4, 2011, 4:54pm UTC](https://boards.straightdope.com/t/uh-oh-rooftop-ice-dam-damage-dammit/569849/31 "2011-02-04T16:54:16Z")

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> [@Fear\_Itself](#):
>
> I saw a story on the news last night where people are filling nylon stockings (panty hose) with ordinary calcium chloride ice melt, then chucking them up on the roof. They claimed that worked pretty well, and the ice dams were broken in a couple of days.

Here in Minnesota, they have been doing it that way for years.

P.S. Remember to ask first, to make sure you get old, worn panty hose. Fixing a roof is expensive, but divorce is even more expensive!

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