Hi,
I have an ice dam problem on an old cape. Major leaks are developing where rooflines come together and with our last big snow storm we had 18″ of snow sitting on an uninsulated roof creating huge ice dams in the gutters and up the roof. What is the best way to deal with this problem…Hazel8
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Replies
A temporary fix is to install some ice melt cabling.
The cables will warm and melt drainage channels to get the water through the dam, and the channels will prevent water buildup.
The long term fix is to insulate from the underside, vent properly, and go topside to install membrane under the shingles.
W. R. Grace makes a product called "Ice and WaterShield" that is used under roof shingles in critical areas of installation.
What is needed is to keep the whole roof at the same tempreture so the upper roof snow does not melt before the lower roof snow where the drains and gutters are. Any heat that brings the upper roof areas above freezing before the gutter area will cause problems. Correct insulation will reduce the chance of this happening. either directly under the roof sheathing if you have any heat source in the attic, or pile it up over the ceiling joists. Remove any wet insulation first.
Hazel8,
It may not be enough to just add insulation into the attic. An important pathway for heat to move from the living area to the attic is through holes in the attic floor. Air that you paid to heat moves through the holes (and throught the insulation that is sitting on top of them (the insulation does do a decent job of filtering dirt out of the air!).
One quick and "dirty" method to discover how big of a problem this is for you is to open a door on a cold clear day. Does air blow in? Open the highest window in the house. Does air blow in?
The more holes in the attic floor, the higher the window can be and still have air blowing in. If, for example, air blows out of a second story window, then the attic floor is in pretty good shape.
Holes in the attic floor include anywhere there are ceiling lights or fans, where wires come up through the top of the wall, the small gap between the drywall and the top plate of the wall, where bathroom exhaust vents and plumbing vents come up through the attic floor. These gaps are easily sealed with a foam gun.
If you have can lights, that is likely more complicated (they cannot be in contact with insulation unless rated IC). Chimneys and other combustion exhausts may require fire proof methods instead of foam.
Rich Beckman
Another day, another tool.
Edited 2/10/2005 11:10 am ET by Rich Beckman
What Rich said, plus consider a Roof Rake to get you through the winter.
Once leaks start, you can sometimes temporarily hold back the flood by shutting off the heat to the rooms below, and closing the doors (if possible).
I finally did climb up on the roof with a shovel and a hammer and pushed the 18" of snow off. I used the hammer to break up(carefully) the HUGE ice dam that had formed where two roof lines come together. I then tried to get off the roof and found that it was much easier to have the nerve to get on the roof than to get off of it.I sat there for a good twenty minutes trying to decide if Iwas better off jumping into a snow bank or risk going down the ladder(my dog found this whole thing very entertaining)I decided to save my knees and risk the ladder. I am hoping to not have to do that again...Hazel8
stay away from the heat cables that sit on the roof. they're a bad idea, a waste of energy, and just a band-aid.
you need better attic ventilation (vents in the soffit/fascia area and vents on the peak), proper insulatioin in the attic, and to stop the airflow from the house to the attic. stopping the airflow is tough, since most insulations don't stop airflow, just heatflow.
"I then tried to get off the roof and found that it was much easier to have the nerve to get on the roof than to get off of it."LOL!! Yeah, I learned that lesson early on. That is why the ladder should extend at least two feet above the edge of the roof. Really makes it easier to get back onto it.Always evaluate how you are getting back down before you leave the ladder...and tie the ladder to the gutter so the wind won't blow it down (I was a very slow learner on that one...probably happened six times I'd bet!).Rich BeckmanAnother day, another tool.
Roof Rake lets you pull snow down while standing safely on the ground.
At least so long as you do not pull ice chunks on your head...