Message Board Thread - "Ice problem after insulation added"

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Ice problem after insulation added eganders 1/4/2008
I had 10 inches of insulation added to the attic of my house to correct icicle problems that were developing. The problem was not resolved. I have added an image showing my problem and some of my neighbors that do not have the problem.

My question: If I had the IR camera equipment, what would I do to find the problem that is causing this. Would I use it in the attic to search for the problem or only examine the outside. Do I have to wait until the snow is gone?

My email: eganders@yahoo.com
 
Re:Ice problem after insulation added IRJay 1/4/2008
It looks to me like it is less an insulation problem and more a ventilation problem. The insulation that was added may have blocked or hindered the air flow up the soffit vents if there even is any. I can not tell from the images if your soffitt is vented to the ridge. Removing this heated air just below the roof deck is crucial in houses. This warm air is melting the snow which forms these ice dams. These ice dams will eventually leak into the structure and cause many issues. You do not need an IR camera to see this problem. You are looking for ventilation to be occuring from the soffit to the ridge. No vents means ice dams.
 
Re:Ice problem after insulation added eganders 1/4/2008
I agree that ventilation might be part of it. Before the insulation was added I looked at the soffit vents and they were clear. I have no ridge vent, just a row of the roof vents in the back of the house (facing west). Keep in mind that my house is the exact same design as many others in the neighborhood. The two other houses shown are of very similar design. I know I have more insulation than they do, but they have little or no icicles. I am about to put a ridge fan up in the attic. It should at least tell me if ventilation is the problem. What do you think? Is that a good tool to check out your theory? Is there any specific place you think I should put a ridge fan that would tell me that additional roof vents or a ridge vent would be the answer? I will check to see if the soffit vents were compromised with the added ventilation.
 
Re:Ice problem after insulation added eganders 1/5/2008
I took a series of IR scans before sunrise with an inexpensive IR gun that has a readout in degrees F. Here are the readings in degrees F:

Snow temp 22-23
cement driveway: 22
outside exterior vertical wall temp 23-28
corner of roof where snow shows melting (rt of porch): 32
Other upper surfaces near roof line: 22-26
Interior vaulted ceiling: 64
interior walls with outside exposure: 61-63
interior walls with no outside exposure: 65-67
Interior of attic roof: 32 at soffits rising to 41 at peak
Attic ridge wall with (outside exposure): 38-39
Insulation temperature on floor of attic: 41

Does this tell anyone anything?
 
Re:Ice problem after insulation added Massachusetts Home Inspections 1/5/2008
IrJay is correct.

For additional information regarding your ventilation issue, GO HERE
http://www.masscertifiedhomeinspections.com/?D=116

 
Re:Ice problem after insulation added eganders 1/5/2008
Here is some information about the soffit area. It shows that the soffits are free of blockage, but there are only active soffit vents on one side at regular intervals. On the garage side the garage roof interferes with having but 2 soffit vents. There are 4 of the roof vents on the upper roof. See photo. I will post an additional photo in a following message
 
Re:Ice problem after insulation added eganders 1/5/2008
Here is a photo of the roof vents. There are 4 in the highest roof area, 4 on the adj roof and 4 on the lower roof (total 12). What type of additional vents can be put in that don't require getting on the roof?
 
Re:Ice problem after insulation added JKEngineer 1/6/2008
The usual ventilation issue with ice damming is that warm air from the interior contacts the underside of the roof. This causes melting on the body of the roof. The edges of the roof, however, tend to not get the same warm air exposure, so that the water refreezes at the edges. This causes the ice dam and icicles at the edges. You may need to look at the air sealing in the attic floor, since that is where your thermal barrier is.

Jack

Jack M. Kleinfeld, P.E.
Kleinfeld Technical Services, Inc.
Infrared Thermography, Finite Element Analysis, Process Engineering

4011 Hillman Ave
Bronx, NY 10463

718-884-6644
866-884-6644 toll free
212-214-0919 fax and voice mail
Skype: JKEngineer

JKEngineer @ aol.com or JKEngineer @ KleinfeldTechnical.com
come see what we can do for you: http://www.KleinfeldTechnical.com

 
Re:Ice problem after insulation added some added info eganders 1/26/2008
I had the installer come and he did some IR scans and there are areas that are warm, but nothing that really explains the problem. He looked at the soffit vents and they are clear. The house has 10 can vents (about 6 in. in diameter), 19, 4X12 soffit vents and 4, 1 ft X 2 ft gable vents. He found that there was condensation (quite moist) in the rear (can vent side) of the roof deck. He also detected airflow in from the gable vents and felt that was not good. We cut some foamcore pieces and blocked the gable vents to see if that would improve the direction of the airflow, hoping that the airflow would now be supplied from the soffit vents.

Does this provide some information that someone can respond to?
 
Re:Ice problem after insulation added Dominion Infrared 1/28/2008
Ventilation already sounds adequate. Homebuilder has a proven ventilation design as evidenced by the neighbors house. Generally speaking, the only thing that can change ventilation performance is bird nesting and blowing excess insulation over vents. Both, which you have already checked out. Sounds like your valuable heat is leaving the thermal envelope as JK suggested. One strike is cathedral ceilings (I’ll explain further), knee walls (which you may have), recessed lighting, air distribution ducts in attic that have been stepped on or become disconnected, unsealed plumbing & hvac chases entering the attic as well as a host of other, smaller, contributing factors. Keep in mind that the smaller factors being referred to are not really enough to cause ice damming. Focus on the obvious. The infrared camera comes in handy during the winter because you can simply stand inside the house and see the cold sections of drywall on the cathedral ceiling. You can also witness this on knee walls & access hatches thru knee walls which need sealing and more insulation. More often than not, the batt insulation over these sloped ceilings is inadequate or not properly installed. If you have recessed lighting or an abundance of light fixtures located in these ceilings, they just tend to exaggerate the heat loss to the attic(usually because they are not rated to be in contact with insulation & thus have large gaps for heat to pass). An energy audit using an infrared camera and blower door will easily detect your problems. Also the use of ceiling fans in the winter will circulate the air nicely. Good resource is the governments energy star website. Once there, search for DIY air sealing and insulating your house.
 
Re:Ice problem after insulation added spongebob 2/12/2008
eganders wrote:
a series of IR scans before sunrise with an inexpensive IR gun that has a readout in degrees F. Here are the readings in degrees F:

Snow temp 22-23
cement driveway: 22
outside exterior vertical wall temp 23-28
corner of roof where snow shows melting (rt of porch): 32
Other upper surfaces near roof line: 22-26
Interior vaulted ceiling: 64
interior walls with outside exposure: 61-63
interior walls with no outside exposure: 65-67
Interior of attic roof: 32 at soffits rising to 41 at peak
Attic ridge wall with (outside exposure): 38-39
Insulation temperature on floor of attic: 41

Does this tell anyone anything?
22 degrees outside,
32 deg. or warmer in attic
snow on roof
sunshine
inadequate ventilation
equals ice dam
 
Re:Ice problem after insulation added StecGuy 2/12/2008
I'm curious to see what the results of the pluggin of the gable vents produces. A small amount of heat will always get into your attic, no matter what, but good ventilation will quickly disperse and remove it, continuously. Gable vents do nothing but disrupt the flow that should be generated naturally from eave to ridge. Hopefully, by plugging these gable vents you can at least establish a better and more uniform air flow.
 


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