The Causes & Cures for Ice Damming:

Ice damming can cause severe damage to your home if the causes are not dealt with in a professional manner. The key to stopping ice dams would involve increasing ventilation in your attic, adding insulation and sealing pesky air leaks within your home. Check with your insurance company to see what is covered in your policy. Ice dams are problematic because they force water to leak from the roof into the building envelope that may lead to:

  • Rotted roof decking, exterior and interior walls, and framing;
  • Respiratory illnesses (allergies, asthma, etc.) caused by mold growth;
  • Reduced effectiveness of insulation.
    Wet insulation doesn’t work well, and chronically wet insulation will not decompress even when it dries. Without working insulation, even more heat will escape to the roof where more snow will melt, causing more ice dams which, in turn, will lead to leaks; and peeling paint. Water from the leak will infiltrate wall cavities and cause paint to peel and blister. This may happen long after the ice dam has melted and thus not appear directly related to the ice dam.

Air leaks

Ice dams are formed by an interaction between snow cover, outside temperatures, and heat loss through the roof. Melted snow from the warmer areas will refreeze when it flows down to the colder portions of the roof’s surface, forming an ice dam.

Although the primary contributor to snow melting is heat loss from the building’s interior, solar radiation can also provide sufficient heat to melt snow on a roof. Seal all air leaks in the attic floor, such as those surrounding wire and plumbing penetrations, attic hatches, and ceiling light fixtures leading to the attic from the living space below. Ice dams are caused by inadequate attic insulation, but homeowners can take certain preventative measures to ensure that they are rare. Increase the thickness of insulation on the attic floor, ductwork, walls and chimneys that pass through the attic.




Missing InsulationThermal barriers such as insulation at the peaks of walls is a common contributor to heat loss into the attic. Uninsulated attic hatches are also a big contributor to heat loss into the attic, as heat rises to the roof decking it warms the decking and contributes to the melting of snow above. Ice dams are usually caused because the attic is warmer than the air outside. Ideally, the insulation keeps warm air in your home and out of your attic. The venting system in your attic helps to keep it cool, and hopefully close to the temperature outside. 




Small House

Many older homes have issues with ice damming due to poor insulation & venting. Some structures will take time & money to correct depending on the construction techniques that were used during construction. 

Airflow & the proper insulation installation in your attic is the key to help in preventing ice dams. Poor insulating methods have also been found in new homes.




Blanket insulation is available as batts or rolls and is the easiest DIY insulation material. It’s available in fiberglass, mineral wool, plastic fibers, and natural fibers. This type of insulation is ideal for attics with standard spaced beams and joists and very few obstructions.

Loose-fill insulation is great for installing in attics with very little headroom and multiple obstructions such as vents and cross-beams. It can be effectively blown over existing insulation and is available in fiberglass, cellulose, and mineral wool.

Spray Foam Insulation This type of insulation is expensive and not a do-it-yourself project, but it has one of the highest R-values at 3.5 per inch for open-cell and 6.5 for closed-cell if installed correctly. Spray foam fills voids & air leaks where other insulation cannot get to. 

Vermiculite Insulation Asbestos building materials were used in homes in the form of, ceiling tiles, vermiculite insulation, floor tiles, plumbing pipe wraps, boilers, roof shingles, siding, joint compounds and adhesives & more. In the late 1970s, the U.S. Consumer Product Safety Commission (CPSC) banned the use of this product asbestos. The EPA strongly recommends that “you should never attempt to remove the insulation yourself. Hire professionals trained and certified to safely remove the material.” Vermiculite has been a popular type of insulation in homes and commercial properties for many years. Unfortunately, a lot of the vermiculite that was used to insulate American buildings & homes in the twentieth century & was eventually discovered to be contaminated with asbestos.


Rated Information! Types of Insulation Can vary and you should choose the best insulation for your needs & application. A minimum of 3” air space is recommended between the top of insulation and roof sheathing in low sloped ceilings for venting. To start off, determine what R-value is recommended for your home based on your location. You can find this information from the Department of Energy. If you aren’t familiar with R-value, it’s basically an insulating material’s resistance to heat flow & is measured by its thermal resistance or R-value. The higher the R-value, the more effective an insulating material is. Your home’s R-value score will guide you toward the type of insulation you need.

Paper Backed Insulation

Never install paper backed insulation on top of other insulation. When improving or adding insulation to your attic and are using rolled or batt insulation always install unfaced rolls. Paperbacked insulation should always be installed towards the heated side below, the paper will collect moisture & create mold issues. This type of installation method is often noticed during inspections & is highly not recommended!

Attic condensation & mold

Install venting baffles in the attic bays roughly 4 bays apart. Over venting can also cause moisture issues within the attic. Make sure insulation is not clogging the soffit venting areas installed with baffles. Here is an attic with clogged baffles & is creating moisture issues to the roof decking and it is starting to blacken. The air temperature in your attic should be within 10* to 15* of the outdoor temperatures. 

Attic Living Spaces

Converting attic spaces into living areas require proper insulating methods. Improperly insulated converted attics can & will create moisture issues on the walls, ceilings & the roof decking that will lead to wood rot and mold concerns. Proper ventilation is also required & vapor barriers must be installed. Make the cozy area that you are creating efficient, comfortable & safe for you and your family. Every attic is different, but a few established norms and practices will guide your renovation.

Gutter maintenance

Installing heat cables can cause more issues than they are worth & there are pros & cons when it comes to installing heat cables to your roof & gutters. Always keep your gutters clean & clear of debris for the proper water flow and make sure your gutters & downspouts are flushed and cleared every spring & fall. 

Contact the Inspector Today! 605-209-6766



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