Ice Dams & Attic Bypasses

If the snow on your roof is melting into long icicles, you may have ice dams on your roof.  Your house may be at risk for leaks into the eaves, which can damage the ceilings, walls and overhangs (soffits).  Ice dams are often caused by warm air leaks from the house into the attic.  Also see our Energy Saver page and our Attic Bypass page.

We are experts at diagnosing the causes of ice dams and frosted attics.   We can show home owners the simple energy efficiency repairs needed to block off the air leaks that are the primary causes of ice dams.  We can often show you these air leaks, either visually, or by our Infrared Thermal Imaging. (IR camera)

Unfortunately, many authorities and so-called experts claim to have remedies for ice dams that either don't work, or increase the costs to heat your house.  A common ill-advised remedy is to increase the ventilation in the attic.  This simply helps pull more air out of the house, and may not solve the problem at all.  Another poor remedy is roof snow removal.  Don't get on a snow covered roof, and don't use metal tools to remove ice or snow.  The roof can handle the weight of the snow.  If the ice dam is causing leaks, the only safe way to have it removed is by steaming.  For more information on ice dam removal, see The Ice Dam Company.

If you have ice dams forming on your house, call us or use the form below to request an examination of the roof, eaves and attic.  Act quickly to prevent costly water damage.  Sealing the air leaks will also save energy and help keep you more comfortable.  See our Infrared Thermography information.  To help understand why interior heat loss is the cause of ice dams, look at unheated garages in your neighborhood.  Those buildings do not have ice dams.

Homes with leaky, damaged, uninsulated or unsealed attic hatches, loose fitting fireplace dampers, or drafty cold dryer vents will benefit from products offered by Battic Door Energy Conservation Products.  To see their products, click on the link below.

These St. Paul area townhouses have ice dams and icy entrances due to complex roof and air leaks from the houses into the attic. Part of the problem in this case is the complexity of the roof design which leads to uneven solar heating of the roofs.   The issue of complex roof designs also occurs on many modern detached single family homes, particularly where an upper roof in sun, has melting snow which drains onto lower roofs in shadow. (Similar to the townhouses shown above).  For homes and townhomes in Minnesota, it is correct to say that "Valleys are villians".  Also see our townhomes page.

Condo roof gables form 52 valleys - Ice dams in abundance

The owners of these 4 year old condos previously thought their problems with a wet basement garage  were a significant concern.  Now they also have suffered ice dams in dozens of locations, many of which hung over their balconies.

The aerial photo of their building shows one of the primary causes of the ice dams is uneven solar heating of their roof due to a roof design which includes 26 gables forming 52 valleys to concentrate the snow melt into massive icicles.

At this point, the condo owners association has incurred an expensive ice dam removal.  Further long term remedies have not yet been determined, but it seems unlikely that the issue will be easily resolved due to the unfortunate and needlessly complex roof design.

Excessive Humidity Damages Attic

This case began as an ice dam investigation, but quickly changed to a general moisture damage consultation, since the damage was far more widespread than typical roof leakage from an ice dam.  Indeed the ice dam was caused in part by typical air leaks from the house into the attic in this remodeled house built in 1973.  In this case, the air leaks were primarily at recessed lights over the bathtub beneath this set of three windows.   Unfortunately, the air leaks, also know as attic bypasses, carried excessive moisture, as well as heat, into the attic.

A central humidifier, installed on the furnace, with its control nearby on the furnace return air plenum, was set to what the homeowner thought was "normal".  Unfortunately, this setting produced an indoor air relative humidity of 45%, which is much too high for Minnesota homes during cold winter conditions. The  outdoor air temperature at 9:30 AM on March 1, 2010 in a Minneapolis-St.Paul suburb was 34º F and the overnight temperature was considerably colder.  

The warm humid air passed through the ceiling via the two recessed lights shown here along with recessed lights in the adjoining shower and other recessed lights in the master bedroom.   Note the position of the lights in relation to the windows.  They align with the snow melt pattern in the first photo.

This photo shows the moldy saturated plywood roof sheathing in the attic above the master bath and bedroom.  Unfortunately, simply drying out this attic will not solve the problem.  Water was literally dripping off the wood frame trusses into the attic insulation as the March 1st sunshine rapidly warmed the roof and attic.  The insulation was getting wet.  Water had also migrated into the walls and dripped out the top of the bathroom and bedroom windows.  Extensive repairs including new roof sheathing, removal and replacement of the insulation, mold abatement, and sealing of the air leaks were recommended.  Finally, either careful control of the indoor air humidity, or discontinuing use of the humidifier was recommended.