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jbenton

Ice Dams In New Construction

4 years ago

I am in the process of building a house. The house is insulated to R49 in the attic (was just insulated and inspected), I also inspected the ventilation and based on my calculations we have more than enough and the soffit vents are open. Also, my can lights and penetrations are all foam sealed. I got a variety of smaller 6-8 inch icicles and a couple larger ones this weekend. We got a late winter storm this weekend that had a mix of snow and sleet, fluctuating temps, etc. Noticed these formed, but was surprised. They even formed off my garage which is insulated but unconditioned. I noticed some of the other homes in the development also got them but not to the same extent. The large ones formed off my two roof valleys. Is this normal for new construction? The house is unoccupied and indoor temp is 65 degrees. How concerned should I be? I don’t remember getting these in prior storms this winter, but the house heat probably wasn’t on. Not sure why I’d get them on my unconditioned (north facing) garage though.


I went to the job site today with the sun out and temps in the 50's the ice dams and icicles are now gone. Wonder how concerned I should get about this.

Comments (11)

  • 4 years ago

    Are you sure you have ice dams? Icicles can and do form without ice damming existing.

  • 4 years ago

    interesting, I think you might be on to something here

  • 4 years ago
    last modified: 4 years ago

    Just out of curiosity, was it a cold day, maybe right around freezing? Sunny day? Windy day?

  • 4 years ago

    Yes, it was a wintry mix day that saw sleet, about 3-4 inches of heavy wet snow, and periods where the temps varied right around freezing. There was also tons of wind. Temps stayed anywhere from about 28 to 30 or so degrees. There was a brief period in the afternoon where the sun almost peaked through the cloudy day.

  • 4 years ago
    last modified: 4 years ago

    My neighbors also got icicles but I think I got them the worst. Here's a pic of the home. This is from earlier in construction but the icicles formed largest in the two roof valleys on the front near the curved roof and to the right of the porch. Additionally, the garage on the right (north side) got lots of smaller icicles, but the garage is not heated (it is insulated but ambient temp in the


    garage was at most 45-50.

  • 4 years ago
    last modified: 4 years ago

    Nice looking home.

    I trust you'll be adding gutters?

  • 4 years ago

    I don't have any experience with houses or weather in such a location but I remember seeing, perhaps on a This Old House or something similar that where snow and freeze/melt/freeze cycles happen, commentary that structures with complicated rooflines are more difficult to properly insulate and design to have enough air movement under the roof. This place would seem to have a complicated roofline so whether that proves to be an issue or not, you'll find out.

  • 4 years ago

    I just wanna say I love your house 😁

  • 4 years ago

    Thank you Yankeeeee and yes, Stax, we are adding gutters, just waiting on the install at this point.

  • 4 years ago

    A suggestion - the cost of 6" gutters and larger down spouts compared to 4" or 5" gutters and smaller downspouts is not much different.

    Seriously consider the 6" gutters and 3" X 4" downspouts!