Why Sealing Attic Bypasses Matters for Minnesota Homes

Taylor Quinlan • March 24, 2022

Attic bypasses are places in the attic where indoor air leaks up, mixing with the outdoor air that is in the attic space. These leaks allow warm air to mix with cold air in the wintertime and cooler air (air conditioning) to mix with warmer air in the summertime. When this interaction is allowed to continue overtime, the results can lead to deterioration of your roofing components such as framing, sheathing and shingles. In the wintertime, especially, this interaction can cause the most damage in the form of ice dams, condensation (see previous blog) which lead to leaking ceilings.

           

Sealing of attic bypasses (as well as other common areas of air leaks) can greatly increase the efficiency of your homes HVAC equipment, increase the longevity of your exterior components and create a more comfortable living space within the home. On average, it is said that the average home leaks enough air as leaving a window wide open all year long! 

A diagram of a roof with a chimney on it.

Ref: Bruce Harley “Insulate & Weatherize for energy efficiency at home” 


Attic bypasses are places in the attic where indoor air leaks up, mixing with the outdoor air that is in the attic space. These leaks allow warm air to mix with cold air in the wintertime and cooler air (air conditioning) to mix with warmer air in the summertime. When this interaction is allowed to continue overtime, the results can lead to deterioration of your roofing components such as framing, sheathing and shingles. In the wintertime, especially, this interaction can cause the most damage in the form of ice dams, condensation (see previous blog) which lead to leaking ceilings.

           Sealing of attic bypasses (as well as other common areas of air leaks) can greatly increase the efficiency of your homes HVAC equipment, increase the longevity of your exterior components and create a more comfortable living space within the home. On average, it is said that the average home leaks enough air as leaving a window wide open all year long!

As illustrated above, air leakage into the attic cavity can come from many different points throughout the space: electrical junctions, sewer pipes, chimneys, etc. In some cases, they can originate from the basement, as is the case with most chimney chases or HVAC supply runs.

           The main objective in defending these bypasses is to STOP THE FLOW OF AIR by utilizing insulation in its many forms. The most commonly used types, for attic bypasses, would be a combination of batt insulation, spray foam and foam board. (link to TCR video blog of MOCKED up ceiling insulation installs)

 

           Each home is built differently with its’ own attic bypasses but the fix is usually the same: STOP THE FLOW OF AIR!

 

Twin City Roofing can assist you in the detection of, and remedy for most attic bypass issues your home may have. 



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