Brand New Roof - Heavy Frost and Icicles

We had our asphalt shingles replaced last summer and we are now noticing some water markings on our ceiling. I went into the attic space to see if I could figure out what is happening. My relationship with the roofer I had hired for the shingle replacement ended on a bad note and I do not feel comfortable calling them back to repair. What I am not sure about is if what I discovered in the attic is normal. I see heavy frost in the rafters and I see icicles stemming down from a few roof penetrations, like the bathroom exhaust fan. I would expect some frost as we live in a Northern climate and the ambient temperature at the moment is -27DegC (-17DegF). I assume the icicles seen are do to some leakage around the plumbing boots for the exhaust ducting? We had ridge venting installed during the roof replacement and there are no other roof vents. Was told ridge venting would be more than adequate, but now I wonder if some addition venting might reduce the amount of frost. Any advice would be greatly appreciated. Is it normal to see this much frost? Icicles in the attic are not normal, is it normal to have to reseal around the boots on a new roof?

-olaf (newbie)

That’s not normal, a few winters like that & your plywood will be junk! Ridge vent doesn’t work without soffet vents as well to create a positive airflow. Were you around when the roof was ripped & replaced? I’m questioning if he actually cut the ridge open or not? He could of pulled a 52 fake out. Can you get a picture of the ridge pole from directly under it? I am also questioning if he actually used ice & watershield or any underlayments.

Funny you mention the lack of underlayments. I found a few places where ice and water shield were lacking. Unbelievable, GAF MASTER ELITE installer, but this is not a post to complain about my contractor. I need to address my moisture issue and I will handle these concerns myself. I can also confirm that the ridge was cut out, about 2" on either side of the peak. I think from talking with others that possibly a relocated bathroom exhaust vent is leaking into the attic since that is where the icicles are located. Wasn’t an issue before roof replacement and duct work of the vent is obviously man handled.

I wasn’t trying to bash anyone, just trying to help you ascertain the situation. Even if that bathroom vent pipe is leaking somewhere internally or externally. It’s not causing all that frost ‘‘all’’ over the ‘‘whole’’ attic. I do see nails penetrating the pipe boot flashing, where there shouldn’t be any nails. It doesn’t look steep, do you have ice dams on the roof right now? That might be the issue. Another thing I’ve seen in the past is when the roof was made too tight by guys applying 100% ice & watershield to a roof deck with no soffet & ridge ventilation. In conjunction with triple pain gas filled windows. The house couldn’t breath. It caused the ceilings to sweat & windows to fog during the winter months when the heat was on. Before the invent of plywood & ice & watershield old time roofers install cedar shake roofs & slate roofs without a problem. They didn’t have black mold problems & ice dam problem. You’re going to have to properly vent that & dry it out or else your going to get black mold (sick building syndrome)

Thanks for the replies to my post. I went back into the attic again today and found a few things.

  1. One bathroom fan (the one in the posted picture) was not insulated and was venting right into the attic. I adjusted the duct to be IN the roof vent as well as wrapped the ducting with duct insulation and spray foamed the duct @ the roof vent. Prior to this work, I had my wife cycle the fan on/off and the air flow from the fan would stir up the blown in insulation. After the insulation and sealing work, I could not see/feel any air movement around the bathroom exhaust fan. I think this duct was the MAJOR culprit to all the frost. I do think some addition roof venting would not hurt. The ridge venting is only cut back an inch or so in several places along the ridge. I’ll put in some additional venting to accompany the ridge venting we had put in when we reshingled the roof.

  2. Electrical penetration blowing air. Found 1 electrical penetration, near the attic hatch, in which you could feel the air moving up from the space below. Spray foam sealed around the penetration and could no longer feel any air movement from below.

  3. Sealed up a few other small places which I could see daylight. It appears I have good soffit ventilation as when I turned off my head lamp I could see daylight in the joist spaces near the soffits.

I think I am well on my way to getting a dry attic!

Stick with static vents then. Don’t use a forced air (electric/solar powered fan) vent as it will suck air in through your ridge vent.

There is usually a “culprit”, glad you found it.

That’s how I solved the problem with that house with the hip roof that was 100% ice & watered. Just like BC said box vents/static vents. They come in cheap plastic or metal. I used the 12’’ metal ones. Real easy to install.

[quote=“olaf”]Funny you mention the lack of underlayments. I found a few places where ice and water shield were lacking. Unbelievable, GAF MASTER ELITE[/quote]

Generally ice and water shield is not supposed to be applied to the whole roof. If you don’t have continuous soffit vents, you might benefit from adding a couple of soffit vents. The intake (soffits) is supposed to equal the exhaust (ridgevent). Adding any other vents has the potential to screw up the airflow. I think you probably already fixed your problem so you might try the “if it aint broke don’t fix it approach” , Im not a roofer but I saw a picture of a roof once.

I’d be willing to bet that your issue is with the bathroom vent. I have seen some crazy stuff with bathroom vents exhausting into attic space; particularly if you have 3-4 people taking long showers each day. Even if there is not a leak in the duct it is possible to run the ducting too long. The bathroom fans generally are not very powerful and can only handle so long of a vent duct before they become inadequate. That moisture however is not coming through the deck. If it was, you would have had a soaked house prior to the winter frost.

I’m with Tar. Dig through the insulation and see if it has been disconnected from the fan housing.

These guys are onto something here bud! Shower steam getting into the cold attic & freezing/frosting up? Or dishwasher/dryer vents too?

[quote=“olaf”]Thanks for the replies to my post. I went back into the attic again today and found a few things.

  1. One bathroom fan (the one in the posted picture) was not insulated and was venting right into the attic.


I think he found the problem already

The OP actually listed 3 different items of concern, which would indicate to me that he was suspicious but not quite sure of the exact problem per se. I was merely confirming his finding and then elaborating on it. Keep the sarcasm.

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