Ice dam on new roof
 

I live in northern Indiana
I am having ice build up on a 10' section of my new roof .There is 13" of insulation and good ventilation
It's over the furnance, dryer and hot water heater that is exhausted out of the side of the house at the sill plate level
I believe that's my problem but how do I correct it?
Merlin1

Is there water standing behind the dam as depicted in this link?

http://www.google.com/imgres?imgurl=...9QEwAw&dur=290

Those plug in heating cables never fail.

Got a picture?

You've only got an R32 rating and the recommendation for your area is between 49and 60,so you need more as is evident by the ice dam you have now,i'll attach a link for a calculator to see how much more you'll need.

http://www.lowes.com/cd_Blown+In+Ins...ator_748453603_

I deal with the same issue every winter. My boiler is a sidewall vent also. The heat from it rises up along the outside wall and gets in thru the soffit vents cousing significant ice damming in that area only. Next winter I plan to test a deflector of some sort in that area.

Pictures would help...

Gary