Feb 21, 2019

The Root Cause of How Ice Dams Form

An ice dam is a sheet of ice that manifests itself on a roof edge.  Instead of allowing the melting snow to filter off the roof, the sheet of ice backs up onto the roof, underneath the shingles, into the soffits, and eventually into the interior of the home causing water damage.  One misconception about ice dams is that they are caused by gutters.  In actuality, ice dams are the result of inconsistent roof temperatures.  Here are a few ways that can happen.

Inadequate Attic Insulation

If you find yourself wondering, “Why do I have ice dams on my roof?” It’s important to understand the primary cause of hot spots on the roof is heat loss from the home which can result in ice dams.  Over time, it is possible for attic insulation to settle, compromising the insulation’s R-value.  In addition, insulation that has become wet from thawing attic frost does little to protect your home.  To prevent ice dams consider installing new attic insulation as it can also significantly decrease your heating and cooling costs.


Attic Air Sealing is Needed For Ice Dam Prevention

It’s astonishing how many homeowners have never seen their attic’s interior.  Therefore, it should come as no surprise that air gaps in an attic can easily go undetected.  Popular spots include areas surrounding roof penetrations and can lights.  These spots allow warm air to escape and come in contact with the cold exterior air, causing the formation of an ice dam.

Subpar Attic Ventilation

Attic ventilation that allows for the open circulation of air underneath a roof can offset temperature discrepancies, making it an effective method for warding off ice dam formation.  The majority of attics are constructed to consider that heat rises throughout a home.  How ice dams form can be attributed to clogged or missing soffit vents because the roof becomes warmed by the home’s interior air.  Attic ventilation also helps with ice dam prevention because it can curtail roof air temperature variations that naturally occur due to sunlight hitting the roof.ice dam

Ice Dams Can Form Around Your Chimney

Routine use of a wood stove or fireplace create a scenario where heat is relocated from the chimney to a home’s attic.  Poorly insulated or cracked ductwork in an attic creates a source of heat.  How ice dams form is largely due to the heat flowing outward and causing variable roof temperatures, leading to the melting and freezing of ice.

Exhaust Fans

Many historic homes have bath or kitchen exhaust fans that blow warm, humid air into a home’s attic instead of outdoors.  This creates an environment for warm spots to form.  In addition, moist air can compromise the integrity of the attic’s insulation.  Exhaust fans should be run at length while cooking and during and after shower use.

How to Pinpoint Causes of Ice Damming On Your Roof

Beware of any contractor that blindly proposes adding more insulation to prevent ice dams.  Thermal imaging and blower door testing allow a contractor to understand where and why warm air is escaping.  With this information, they can put together a customized plan that addresses the root cause(s) of ice damming on your roof.  Learn  more about ice dam prevention.

Here’s How Blower Door Testing Can Determine Where Your Home is Leaking Energy:

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Attic Insulation Reviews:

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Janis H.
Hammond, WI
May 21, 2022

"On two occasions, Randall was at my house involving insulation issues.  He knows the business, is easy to work with, and I think he is a great asset to your company."

Mary W.
Maple Grove, MN
May 2, 2022

"Excellent and efficient work. Thankful that the Lindus crew was accommodating to our needs as homeowners and for their communication throughout."

Bloomington, MN
April 19, 2022

"Had Lindus blow in foam insulation into attic, what a difference it’s made! The house is noticeably warmer in the winter and my furnace is not running nearly as much as before. I know it will also help keep the house cool in the summer heat. They also installed some new windows and exterior trim. Everything turned out really well. Corey Hessler was fantastic in dealing with from start to finish and answered all my questions. Everyone I dealt with from Lindus, especially Corey, were kind and professional. In today’s day and age you get what you pay for. Lindus really delivers!"

Robert M.
Cottage Grove, MN
March 25, 2022

"We highly recommend Lindus Construction. They showed up everyday and did quality work. Very professional, polite, and answered all of our questions and concerns. The work ethic we saw was superior. We’re very pleased with the insulation and venting project they just completed. They get the highest a 5+ rating from us."

Lee Ann S.
Maplewood, MN
February 4, 2022

“I want to thank and commend Andy Lindus and his crew for a fantastic job.  I recently had my attic completely foam insulated and had some new windows installed.  Everything turned out fantastic.  I am very pleased.  I do have to note that the foam insulation made an immediate difference in keeping my house nice and warm this winter which helps on the heating bills.  Thanks again!”

Rob L.
Cottage Grove, MN
March 19, 2022
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