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    Troubled Houses - A Home Owner's Resourcesm - Ice Dams

We see many interesting adverse conditions during our inspections, partly because of the unlimited number of ways people can mess up a house, but also because we do a thorough inspection to reveal these adverse conditions. We hope these stories help home owners avoid these costly conditions by learning about causes, preventions, and remedies. A home purchase can create opportunities for the new owner to improve the home, possibly increasing its value, durability, and usefulness.

NOTICE TO BUYERS & SELLERS: This site does NOT encourage or discourage the purchase of any individual house, or style, age, location, or condition of house.  Conditions shown and/or described in the following articles may have been remedied at the house where these conditions were found.  These conditions typically can be remedied by qualified contractors. The presence of these conditions in any house is comparable to any other real estate consideration such as price, size, or location.  Consult a qualified home inspector before purchasing any house, and consult a qualified real estate agent for more information on how to handle a real estate transaction where adverse conditions are reported in a home inspection.   This site does not describe any house by address or knowingly show a readily identifiable exterior image.  Further, no home actively listed for sale  will be described on these pages at the time the article is posted.

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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. 

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.

Lower Your Home Energy Bills!

(C) 2014 Ice dams over townhouse entries. Troubled Houses photo by Roger Hankey, ASHI Certified inspector, Winter Park, CO

These 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 cold snow regions, it is correct to say that "Valleys are villians".  Also see our townhomes page.

Condo roof gables form 52 valleys - Ice dams in abundance

(C) 2014 Ice dams on multi-gabled condos Photo by Roger Hankey, ASHI Certified Inspector in Winter Park, CO

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.

                                                           Many gables and valleys on condo building

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

(C) 2014 Roof snow melt pattern with recessed light hot spots. Photo by Roger Hankey, ASHI Certified Inspector in Winter Park, CO

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.

Central Humidifier control set to "Normal".  Photo by Roger Hankey, ASHI Certified Inspector in Winter Park, CO

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 34ยบ F and the overnight temperature was considerably colder.  

(C) 2011 Bathroom ceiling with recessed lights.  Photo by Roger Hankey, ASHI Certified Inspector in Winter Park, CO

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.

(C) 2014  Moldy wet roof sheathing.  Photo by Roger Hankey, ASHI Certified Inspector in Winter Park, CO

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.  

Valleys are Villians

Builders continue their love affair with gables and valleys.  The result is homes, condos and townhouses built recently with severe ice dams.  These ice dams are NOT the result of poor insulation or ventilation.  These ice dams would not exist if the roof design were less complex.

 (C) 2013 Large ice dam formed on roof below valleys on North facing slope of modern townhouse in Minnesota. Photo by Roger Hankey ASHI Certified Home Inspector in Winter Park, CO

The building shown above faces north and has a massive ice dam below a valley facing the NE.  Gable #1 shades the area between gables 1 & 2 in the morning, but the sun warms the east facing slope of gable #2.  Gable #2 shades the area between the gables in the afternoon.  The snow melted in the morning freezes on the north eave between the gables or runs off the unguttered eave and freezes on the cold lower roof of the garage eave. This water drains off the right valley and forms a massive icicle at #3. There is so much snow melt and ice that the water runs off the lower roof and its gutter  and freezes on the driveway at #4.  The building is one of 3 similarly situated buildings built since 2010.  Installation of rain gutters on the upper eave may help reduce the problem on the garage roof, but will not eliminate the ice dam.  This could have all been avoided with a simple roof design without valleys and without an upper roof draining to a lower roof.  This roof will probably have to be equipped with heater cables to melt ice in future winters.  Alterations to roof ventilation and insulation are unlikely to reduce the ice dam, since this modern building meets Minnesota insulation and ventilation requirements. 

      Big Valleys & A Big Gable + A few gaps & heat losses to the attic = Big Trouble

 (C) 2014 Exterior of townhouses in Central Minnesota with roof design that increases the potential for ice dams & leaks. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO
The center portion of the roof of these townhouses has had much of the snow removed to help reduce the potential for ice dams.  The large center gable is one of several factors that created the ice dam. The gable creates two long valleys that end nearly over the windows that suffered leakage from the ice dams.  The ridge of the gable casts a shadow along the lower portion of the front roof above the window at right of the gable.   Midday sun can warm the upper roof causing snow to melt with melt water flowing down to the shaded area where it can refreeze as an ice dam on the eave.  There is no remedy for this built in design flaw, although heater cables on the 

Another factor in creating the ice dams was found in the furnace closet of one of the center units.  The furnace vent pipe and air intake pipe ceiling pentrations were not sealed.  This permitted warm indoor air to enter the attic around the pipes.

 (C) 2014 Air gaps around furnace vent pipes into attic. These increase the potential for ice dams and waste heat. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO  (C) 2014 IR thermal image of air leaks around furnace vent pipes into attic, increasing the potential for ice dams and wasting heat. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO
The photo at left show the air gaps around the pipes.  The IR thermal image shows warm air around the pipes.  The intake pipe is cooler, but had a warmer area next to the ceiling, consistent with a larger gap around the pipe.  We recommended these gaps be sealed with foam caulk.

The attic insulation was blown white fiberglass, but this had been trampled in several areas by human foot traffic in the attic.  Also on of the units had a dryer vent that was loose at the roof penetration.  This vent discharge hot air and lint onto the underside of the roof.  We recommended corrections by a qualified insulation firm.
 (C) 2014 Trampled attic insulation, increasing the potential for ice dams and wasting heat. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO  (C) 2014 Loose clothes dryer vent in attic, increasing the potential for ice dams. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO

The infrared thermal camera revealed the most significant ice dam causal factor hidden beneath the insulation.  The ceiling area immediately adjacent to the fire wall between adjoining attics had a hot spot.  Moving the insulation off this area revealed that there is a gap in the framing that permits warm air to rise into the attic.  We recommended corrections by a qualified insulation firm. (Spray foam or rigid foam insulation to stop this air flow.)
 (C) 2014 Gap at ceiling near adjoining attics, increasing the potential for ice dams and wasting heat. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO  (C) 2014 IR thermal image of gap at ceiling near adjoining attics, increasing the potential for ice dams and wasting heat. Photo by Roger Hankey ASHI Certified Inspector in Winter Park, CO


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