Here in the northern part of Indiana, this time of year following Valentine’s Day is the prime time for Ice Dams to accumulate on your roof.  Ice dams form when the heat from your home escapes through the attic, warming the roof sheathing and melting the snow layer on the roof.  This melted water will eventually freeze again once it reaches the eave, resulting in a dam that blocks the roof drainage.  Regardless of the roofing installation, this can result in water backing up under the roofing materials and cause costly water damage to the interior of the home.  

Let’s dive into  what’s really causing the ice dam to form and help you have a better understanding of how to prevent it.

What is causing the ice dam?

Air Leaks:  Any gap, crack or joint between the heated air space of the home and the attic can be one of the main causes.  Gaps around recessed can lights, ceiling mounted electrical boxes, plumbing vent pipes, and exhaust fans are all culprits of air leaks. 

Poor Insulation:  If your attic does not have adequate insulation, you’ll have heat loss into the attic space.  If you have blown cellulose or fiberglass insulation it is important that the proper amount of fill is even and up to code.   Quick inspection tip:  If you can see the ceiling joist framing, your ceiling is under-insulated.   Poorly installed fiberglass batt insulation can also be the cause of heat loss. 

Poor Ventilation:  If the attic is not properly ventilated this too can be a cause of damming.  Sealing air leaks and correcting the insulation should be remedied before addressing any ventilation issues.   Improving ventilation in an attic with air gaps and poor insulation may draw more warm air to the attic creating even more ice dams.  If you have ventilation concerns, discuss with a local insulation contractor for remedy solutions.  

Roofing Waterproof Membrane:  Self-adhering waterproof membranes (Ice and Water Shield) are a code requirement in Northern Indiana at the eaves of any roof over a heated space.  In the event of unusual weather conditions, Ice and Water Shield is your last line of defense.   Contact a roofing contractor to inspect your roof for proper ice and water membrane installation.

How to fix an Ice Dam?

Seal Air Leaks:  The best course of action is to find a home-performance contractor who knows how to identify air leaks using such tools as a blower door or an infrared camera.   They may seal any gap, crack or joints with canned spray foam or rigid forms of foam insulation.  

Add Insulation:  Cellulose or fiberglass can be blown atop the existing insulation to add more depth.  Contact a licensed insulation contractor for an inspection and discuss available options.