Ice Dam Issues
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- čas přidán 22. 08. 2024
- Do You Have Ice Dam Problems?
If your home has a steep sloped roof, and is more than 20 years old, there is a high probability that your attic has excessive heat, leading to ice damming. I spent some time this weekend removing ice dams from my house. Here are some thoughts:
What Is An Ice Dam?
An ice dam is a ridge of ice that forms at the edge of a roof and prevents melting snow (water) from draining off the roof. This water often backs up behind the dam causing leaks into a home and damaging walls, ceilings, insulation, and other areas.
Ice dams usually occur after a heavy snowfall followed by several days of freezing temperatures. An ice dam forms when warm air inside your home leaks into the attic and warms the underside of the roof causing snow and ice on the roof to melt and drain down to the roofs edge.
The melted roof water drains along the roof, under the snow, until it reaches the cold overhang. The overhang tends to be at the same temperature [below 32 degrees] as the outdoors and the melted water freezes at this location and builds up. Icicles are often an good indication that you have an ice dam.
Removing An Ice Dam
What Causes Ice Dams?
The most likely causes of ice dams are due to heat loss, air leakage and the general warming of the house structure due to conduction from the heated building.
Ice dams are usually caused by heavy snowfall and improper ventilation, insulation and air leak sealing in the attic. This causes warmer areas in your attic then the snow begins to melt, even when the outside temperature is well below freezing.
When the accumulated snow on your roof starts melting it runs down your roof underneath the snow until it reaches the "colder" colder overhang. The overhang tends to be at the same temperature [below 32 degrees] as the outdoors and the melted water will refreeze and form an ice dam and icicles.
Other areas like the valleys or in gutters then it begins to freeze again, this process of thawing and refreezing is what causes an ice dam.
The photo above: [2nd story house with ladder and icicles] is my house. It was built in 1863 and renovated in 1993. This area of the roof has 2x10 rafters and fiberglass insulation with baffle "proper" vents that travel, a long way in the rafter bays, to the ridge venting.
Insulation is minimal and air leak sealing was not done well. At that time I did not know a lot about ventilation and installed a Hix Vent which is now covered in ice. Currently there is no access to address insulation but I can do one thing to improve these conditions. When re-roofing I added a continuous sofit vent to improve ventilation.
Dealing With Ice Dams:
snow raking roof
1. Immediately after it snows, remove snow from the roof. This eliminates one of the ingredients necessary for the formation of an ice dam. A “roof rake” can be used to remove snow.
The photo on the right [white cape] is an excellent example of a roof that was raked after a storm. The removal of the snow has allowed the sun and warmer temps to melt ice and snow allowing this roof to drain easily and with out dams.
2. In an emergency situation where water is flowing into the house structure, making channels through the ice dam allows the water behind the dam to drain off the roof. Snow melt can also be used to facilitate these channels. DO NOT walk on any snow covered roofs!
Carefully chip away a channel through the ice dam allowing trapped water to flow off the roof, stop chipping when you get close to the roof surface. Make several channels along the roofs edge. I suggest every two to three feet to allow water to drain and snow melt to drain.
Removing An Ice Dam:
WARNING! Performing ice dam removal is risking severe personal injury and damage to the roof if not done properly. Never walk on a snow covered roof and make sure if your using a ladder you follow the proper safety procedures. I use a ladder with a stand off attached, making sure the stand off touches the roof and is embedded in snow. I also tie off the ladder when applicable.
I highly suggest contacting professionals with the proper equipment and roofing experience to carry out this job.
Thank you Robert. I have been following you through your newsletter and youtube for years. I really appreciated the thoughtful and in depth discussion. For years, the knee jerk reaction to any discussion on ice dams has been "all you need to do is insulate and ventilate". No doubt, the insulation and roofing manufacturers have had much to do with keeping this mantra alive. There are certainly cases when that is absolutely needed. But, as you have pointed out, and we have been saying for years, complex roof design is a huge factor that will not be helped by those efforts. You also pointed out that 'air sealing' is vital and should be the first step. So many skip this step because of the difficulty in doing it properly. Here at Edge Melt Systems, we get so many inquiries on how to solve ice dam problems. While we do manufacture roof and valley radiant heat panels, air sealing is always part of the discussion. Thank you again for the video.
Thanks - appreciate it. I like your product, its a great solution
Thx Robert. Let us know if you would benefit from trying it on an upcoming project. Would appreciate an experts opinion.
Haha - you guys are the experts. Im interested. Let's chat - robertrobillard@comcast.net
So much bad advice in here. Using a hammer causes so much more damage, nylons filled with salt do not work there's plenty of videos on the internet to show that. Throwing salt on your roof is a terrible idea rots out nails and causes larger future issues. This guy may be a professional at many things and he's correct about using steam but there's plenty of bad advice here.
Very good video. You have given a lot of caution tips.
Jody Hakala thx
I lived in Stockbridge Mass when I was a kid. We had a three story house and one winter in the mid 1960's we had a 3 story icicle. It was 5 inches in diameter at the bottom. I was very young and I went out and broke it. I don't remember the structural consequences of that but I imagine it didn't do the gutter much good seeing it was a few feet wide at the top.
Good information, only thing I miss is information for those who plan to build. A low roof pitch is the primary cause for these issues. We often have ice on the lower section of the roof, but at 50° roof pitch they will never hold back any water.
The pitch of the roof is a factor, but if there is sufficient snow and the "right" conditions, water can still pool and find its way inside. I have witnessed, here in the north Cascades of Washington, ice dams over 4' high. Even on a 12/12 pitch this can create a lake at least 2' deep. I learned the hard way to not work from below, when knocking through the wall of ice.
Nice Job, Very Thorough. I'll refer this video to clients as well.
thanks
When putting hosiery with salt tie a string ! Helps do you can move it, and Remove them.
Hi Robert. I appreciate your efforts, but I disagree on two very important things you say here. First... if you clear snow off the bottom 3'-4' as suggested, be prepared for a new ice dam at the new snow line. Often there is no ice guard up there, and it will leak. Second, never use a hammer to hack ice up on a roof. Shingles are cold and brittle and will easily be damaged. Besides, these 'channels' you make will freeze up again overnight and you have what you started with. And I guess one more thing. . . every manufacturer of ice and water shield membranes had lots and lots of failures this winter. Wish they were reliable, but they aren't.
jktr1 Thanks for your comment and your correct a secondary dam can and has occurred. Realistically ice is mostly forming on the cold roof edge and not in the higher warmer section.
While clearing the entire roof of snow would be best it is often not feasible for most folk.
The hammer is not the preferred method but when you have water leaking into your house you need to use something to drain the water - this winter was exceptional and many people could not get a contractor to come to their house. I saw many different implements being used - and will most likely be repairing some of that damage this spring.
+jktr1 I have had the problem of an ice dam about 4 feet up when I did not remove snow from the whole roof as well. Better to do the whole roof or nothing and having the long ice-cycles and dripping down the siding than damaging the ceiling inside. I think the biggest problem is having no waterproof membrane.
I've seen this and the dam is mostly ice on the edge not a "real" thick, solid ice dam that forms on the roof edge. I agree is you can remove all of it or reduce all of it significantly - your in better shape
Wow!!! What a dilemma!!
I just removed the ice dam on my roof using de-icing cable. Just threw it up on the roof & looped it, let it melt until I could toss the chunks off the roof.
Solid advice Rob.
Ice Dam Issues: Tips for Prevention and removal
We have have fans up in the crawl space. We need more insulation! We need to get a taller safe ladder! And hammer that ice shit like Thor!
Then prevention. The neighbors even said this is the worst icicles and year for ice dams in 8 years!
Thanks for the Suport
I'm unclear on what you're saying about roof/attic vents. Are you saying they are unnecessary and should be removed or blocked up to no air gets in/out of your attic/crawlspace etc?
Nunya Biznis They're very important, but if you have significant heat loss from the house that heat will go up through your eave vents and cause the problem they're supposed to be solving. If you have cold air venting through the eave vents you will not get ice dams.
Hi good video, I have a ice dam on the north side of my two story house and roof rake does not reach. My question is can I fill my water fire extinguisher, that uses compressed air and liquid, with antifreeze and spray the roof just higher than the ice dam? What are your thoughts?
Thanks
Lyle Kinar not sure lmk how that works
Great Video!!
Hi Robert....Thanks for the info...appreciate the efforts!...Question?....I have a Cape Cod style home, two dormers in the front, with a fairly flat rubber membrane roof over the front porch. To prevent ice damming on the rubber roof would (or advisable) it work if I placed calcium chloride filled nylons inside the gutter all the way across the front of the porch BEFORE it snows and leave them throughout the Winter season?
I have a cabin style house . I have no attic. From my ceiling to my roof is about one foot. Would it be wise to foam insulate my roof hoist from inside and insulate my ceiling??? Gf wants to ya to build another new roof lol. Wats your suggestion??????
Yes insulate the ceiling joists
Thank you
great vid - thanks for sharing that with us
Here watching this video in Chicago after 9 straight days of snow including 18” yesterday. Now there are ice dams and I have water dripping in through a wall somewhere with damp carpeting and wall trim. Ugggghhhhhhhhh. Good video, very informative. Thanks!!!
Alcohol works just as well if you don’t want to spend 2500 on flir. Camera.
robert you forgot one sure cure >>move to florida
Definitely don't move to Texas.