Why Do Ice Dams Cause Mold?

Why Do Ice Dams Cause Mold?
Recently got mold?™ was called by a customer that is experiencing mold caused by an ice dam. The long winter in Saskatchewan and Alberta and snow accumulation on roofs is leading to significant ice damming problems which ultimately could lead to mold issues. Pictured below is a home in Calgary that will have ice damming issues…notice the icicles!

Calgary Home With Ice Dam

HOW IS AN ICE DAM CAUSED?
According to the Ice Dam Company ice dams result from the escape of heat into the attic which eventually builds up and melts snow on the roof. The ice dam is the ridge of ice that forms at the edge of a roof which prevents melting snow from draining as it should. The water that backs up behind the ice dam can leak into the home and cause damage to walls, floors, ceilings, insulation, and other areas. This graphic, courtesy of the Ice Dam Company, provides you with visual warning signs to look for.
Pictured below is an image of a house we inspected. Apparently this home was just renovated, but the builder failed to insulate the attic properly and the end result was a significant ice dam, which ultimately will cause problems for this homeowner. Ice dams are preventable!

icedam

WHY DO ICE DAMS CAUSE MOLD?
The key problem caused by ice dams is the water and moisture that leaks into the home. Mold thrives on moisture and grows because it feeds on the materials that most homes are made of: wood, drywall, wallpaper, carpet, ceiling tiles, etc. The final component required for mold growth is a temperature of 5 degrees to 38 degrees. As long as these three ingredients are present, mold will form and continue to grow provided it has food to feed on. This is the reason that the structural integrity of a home is compromised–mold is essentially feeding on the home.
As mentioned earlier, ice dams are caused by heat escaping into the attic. Temperature, as you know, is one of the key ingredients required for mold growth. Heat in the attic, which leads to ice dams is caused by everyday activities in the household, such as cooking, laundry, showering, washing dishes, etc. Normally, these activities should not cause problems, ie. excessive condensation and heat in the attic. However, problems will occur if the attic is not properly insulated. One of the major causes of condensation in the attic is the lack of proper ventilation in the kitchen and bathroom required to vent vapour out of the home. Another major reason excess heat may build up in the attic is a direct result of builder negligence that vent bathroom and dryer vents into attics, crawl spaces, or over hangs, and not onto the roof. This poor building practice will cause problems because moisture and heat will build up in the attic. The Ice Dam Company provides an excellent visual of why black mold begins forming in an attic…click here to view.
Here are some general tips to prevent ice dams.
1. Make sure you have proper ventilation in the attic. Keep your soffit vent clear and open. Have a roofing professional check your roof and calculate the proper ventilation requirements. A well ventilated cold roof prevents ice dams.
2. If you have gutters on the house – keep them clean and free from leaf debris.
3. Ensure that your bathroom exhaust is vented through the roof and insulated if necessary.
4. Ductwork in the attic should be well insulated and sealed from leaks.
5. Air bypass – where warm air leaks through small cracks and openings – should be sealed. Check attic access ports in closets and can lights in the ceiling as potential areas of concern.
HOW DO I KNOW IF I HAVE CONDENSATION ISSUES IN MY ATTIC?
In addition to the visual external clues of ice dams, here are some tips to help you determine if you have condensation issues.
1. Check your attic for visual mold.
2. Check all penetrations in your ceilings such as light fixtures and make sure there is no excessive gaps between the fixtures and ceiling.
3. Make certain all drywall is finished properly with no gaps or cracks for moisture to migrate through.
4. Look for visible stains such as mold on the surfaces of the ceiling, walls of the living areas, floors, carpets, attic plywood sheathing, attic sidewalls, floor joist, wet insulation.
5. Check for moisture or high relative humidity over 65% and higher.
6. Smelling unusual musty or moldy odors is an indication that you may have a problem. High relative humidity or moisture may be the culprit.
If you are concerned that you may have ice damming issues, we recommend that you hire a professional to assess the situation
We are here to help, so please do not hesitate to contact us. A mold inspection is a cost effective solution to determining if you have to worry about ice damming, and the potential moisture and mold issues it causes. Peace of Mind, just a phone call away! Toll Free: 1-888-909-MOLD (6653)