Attic Insulation and Ventilation

Most homeowners do not realize the importance of proper insulation and ventilation when it comes to improving the efficiency of thier home. Attic ventilation is necessary to prevent moisture problems and heat build up which can shorten roof life expectancy and reduce cooling efficiency. Proper installation and amounts of insulation at the attic will also limit heat and cold transfer from the interior living space to and from the attic.


In the summer, heat builds up in the attic space, which will cool at night if the attic is properly ventilated. However, if the attic is unventilated or ventilated incorrectly, the heat will build-up over a period of days and continue to increase the temperature inside the attic.



A 90-degree day with no attic ventilation can heat the roof sheating to 170 degress or more. Heat readiating from the sheathing down to the attic floor can raise its temperature to as much as 140 degrees. Without adequate ventilation, today's heavier insulation will absorb and hold more heat built-up during the day and make the attic less likley to cool at night. Overheated ceiling insulation conducts the heat through the ceiling down to the residents of the home. This causes the air conditioning system to operator for longer periods of time to reduce the heat.



Under these extreme temperatures, roof sheathing material can also delaminate, becoming brittle and hazardous to walk on when traversing your roof. It can also delaminate to the point of requiring complete replacement at time of tear off and repalcement of your roof covering, raising roof replacement costs significantly.







For more information on Attic Insulation and Ventilation, and links to a homeowner checklist for proper ventilation, visit our website: abouthomeinspection.com , and click on the Attic Ventilation link.



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