Preventitive Measures for an Ice Dam


During two REALLY bad ice storms here in Iowa, a huge ice dam formed in one of the valleys of my roof. Here is a picture of my house… The ice dam formed in the valley where the garage roof meets the siding of the second floor: … -52233.jpg

I have had roofers out and they all say there is nothing “wrong” with my roof but there are steps they can take to prevent something like this happening again (although nobody will give me any guarantees). I should also mention they all told me that usually the root cause of ice dams tends to be insufficient attic insulation/venting, but in this case, the storm created a giant block of ice within a couple hours, then it started raining, so the source of the water was the sky and not melted snow.

The best estimate I got was for $450. They plan on doing the following:

-Take off original shingles all along the valley.
-Put Winterguard all down the valley. He said the stuff is 3 feet
-I remember him mentioning something about step flashing. I think he
wants to add some down the slope of the roof where the roof meets the

  • He mentioned using some sort of roofer’s tape to tape off the top of
    the flashing so ice can’t get in back of it.
  • I think he said something about adding a special piece of siding
  • Match the shingles and replace.

He didn’t say anything about replacing any of the decking, just making
what is up there water tight.

He also plans on doing it soon, and the temps are below 40 (should I be concerned with that)?

Does this sound reasonable, or are they just trying to take advantage of someone who is desparately looking for a solution? Will doing this help at all?


Your photo is a bit small for me, but I’ll edit you a bit so it’s not a click away.

I’m also NOT going to be your best resource as I have zero snow country experience & have done all my roofing in Texas / Lousy-Anna / Flori-Duh (Central Texas here, as my roofing brethren know).

The 3’ you mention is 3’ wide & not “thick”… it makes an extension from your valley metal to the deck preventing water intrusion.

Beyond that, I’m not going anywhere near your situation. I’m learning the cold weather stuff as I go along on this site.

I’d suggest a bit closer on the photo of your "affected area’ & especially one that shows your concern in it’s currently frozen state.

This looks like a classic “bad area”.
A closer picture is needed.

There is probably a saddle in there.
If not it needs one.

You should take off all the siding in the repair area. Remove shingles as needed, 4’ away from the walls should be adequate.
Remove all the old step flashing and felt to bare deck.
Fix wood as needed.

Apply Ice & water shield to the entire repair area.
In the area around the saddle, up under that tight little soffit, apply Ice & water shield to the entire wall.
Inside corner and everything, all of it.
Fold your inside corners, don’t cut them.
Tie into the little valley that drains into this area.
It is not a very big area, One 2 sq roll of Grace will probably do it.
Use new step flashing and shingle as usual.
Replace siding when you are done.

It is critical that you do the tie in to the valley correctly.
It is a small valley so really no reason not to just remove and replace it and include it as part of the repair.

Your Roofer probably has something similar to this in mind.
Based on a 3rd hand description, it sounds like he knows what is up.

If I repaired this as described I would Give a 5 yr warranty if requested, there is pretty much no way it can leak.
It is not a cheap repair though.

You may not even need this repair, this ice storm was a freak of nature.
If you don’t have problems during a normal winter and the roofers say there is nothing wrong with your roof.
You probably don’t need to do anything.

you mentioned the “best” price you got was $450. i think you meant to say the “lowest” price you got was $450. cheapest doesnt mean best :!: if its not leaking right now…dont touch it until spring.

You have ice and covered snow on your roof.

An ice dam forms due to heat loss at the upper thresholds of the roof surface areas and then refreezed at the soffit eave overhangs.

The number one question is:

Do you have any ongoing leaks occurring from this act of nature?

Answer that first before I give you more details.


No, the roof stopped leaking shortly after the freezing rain stopped.

Without a clear ppicture of the ice dam that occured on your home, it would just seem that you have a problem dead valley area where all of the accumulation gets trapped in a small pocket. I don’t think you need immediate roofing surgery, but a way to melt the ice.

On another forum, ice dam removal was being discussed and I mentioned these products. I would thing that the tubes from Ice Viper would be your most cost effective melting solution, available from Ace Hardware and Menards and Home Depot.

Magnesium Chloride Flakes, mixed in with water, creates a more effective ice disolving solution, for a relatively cheap cost.

I will check my favorites that I have bookmarked and post some links.


One link at a time via edits. I will be back with more information. Some of it is on paper form, and I don’t have it bookmarked on this computer yet. this is the one I was talking about in a laer post. Ice Ban. this one is readily available, called Bare Ground, available from this outlet, directly linked from Bare Grounds home page store link.

sounds like a lot of work for $450. Thats a band aid price.