HELP! Ice in attic.

For the past 2 days, my wife has noticed a small wet spot on the inside of an outside wall. Curious that it might be coming from the attic, I went up (we have pull-down stairs) to check it out. NOTE: We live in Maryland where temps were in the teens last night. I noticed that ALL the nail tips from the roofing shingles were covered with thick frost, as were the side walls. I didn't want to have the hatch opened for too long, so I took a quick look around, but didn't see anything overtly dripping down the wall where the wet spot was. Is what I've described about the attic frost a normal condition? Can anyone help? Thank you.

David

 

Yes, especially homes with no insulation in their attics. I would probably insulate your attic soon. The frost tells me that alot of heat is escaping upward from your home. You know, warm air hitting cold air. When this frost does melt, you know which way the water drips don't you. Thats how wall leaks or ceiling leaks get started.

 

The attic IS insulated, albeit, not very well - about 4 inches of blown fiberglass. Lack of insulation is complicated by a floored-in attic for storage. I've been trying to figure out how to raise the floor to add more insulation.

But the house is 40 years old. I would think that this problem would have come up before this. I suppose it's possible that the leak could be from the pull down stairs that were installed in Summer of '99, but we didn't have this problem last year.

Oh, well. We'll keep an eye on it. Thanks for your input, and any additional help is always appreciated.

David

 

One thing you could do, is hang a therometer down into the middle of your attic, half way between the floor and the ceiling. If the temp is 45 degrees or higher, you will now you have too much heat leaking into your attic. Also, a leak is a funny thing. Even though there is a leak, it may not show up for some time. For instance. One time in our house we noticed a leak. So I put a coffee can under it as I was too busy to fix it. Dumped the can once, and replaced it. It never leaked again for 11 years, until we re-roof our house. Thats how it is.

 

I would be willing to bet money that your attic is severly under ventalated! Try this, measure your attic floor space. Measure the ceilings below, its the same thing. Code stipulates one square foot of ventilation for ever 300 square feet of heated attic floor. So if your attic is 30 by 20 feet, 600 square feet, you require 2 sqaure feet of venting. One at the perimeter,(intake) ususally the soffits and one square foot at the top for exhaust. That is only one aspect.

Idealy, under the insullation, you have a vapour barrier to keep the warm, moist air from the home from enterring the attic, however do you have weatherstripping around your pull down stair case? It sounds like the moisture in the attic, likely coming from the house, is condensing and freezing to the roof sheeting and exposed nail tips. The sun hit the roof during the day, warms up the attic, the ice melts runs down the sheeting and drips onto the ceiling.

 

Jacksprat:

Where have you been. Have'nt heard from you in awhile.

 

Jack,
Thanks for the information regarding the frost inside the attic! I've had the same problem for the past 4 winters. One contractor suggested that I have "gable fans" installed (which I did) to help keep the air "moving", but that didn't help. Nobody ever suggested that it was a lack of insulation!
Question: I have the "blown in" type of insulation. Would you suggest I have more blown in, or do you think it I'd be better off paying to have the blown in insulation removed and replaced w/ the solid roll-type insulation? Thanks again!

 

As much as you may require, or desire more insulation, the crux of your problem may be the lack of air coming IN to your attic. Make sure that the insulation is not tucked, or blown over the top plate of the wall below and that air is coming in by way of the soffits. If this is not practical given the construction of your home, several conventional roof vents as low on the roof as possible should help alleviate some of this problem. Use the prveously merntioned formula to figure out your needs. Good luck
Jack

 

I had several additional roof vents installed when I had a new roof laid several years ago. In addition I have an electric "gable fan" installed, so I would think there is more air coming in now than ever.
Question: I noticed last night that the exhaust pipe from my furnace opens up inside the attic and is blowing hot exhaust straight up towards the attic ceiling, in almost the exact area where I'm accumulating massive amounts of ice. Shouldn't that exhaust pipe extend all the way up through the roof and release the exhaust outside??

 

PEOPLE DIE FROM THIS!!!
If you are sure that this is the furnace stack, have it fixed tommorrow! The exhaust MUST vent directly to the outside, as must lavatory exhaust fans, now that I think about it, everything goes out.

Okay, have it fixed tommorrow. What would happen is that any moisture, and beleive me there is lots, in the exhaust would condense upon contact with a cold surface. You probably have found the root cause.

Stay in touch, and put new batteries in your CO2 detector tonight. P.S. Gable fans are often controled by a thermostat that only vent the attic when the heat level rises above intolerable.

Let me know how it goes...
Good luck
Jack

 

Jack is correct. it used to be up until maybe 5 years ago, that many exhaust vents just dumped into the attic. This is a no no. They must vent to the outside. No exceptions. No matter where you live. You have just found out where your frost is coming from.