How Cool is Your Attic?

Home Inspector with Master Home & Building Inspections, LLC MD Lic 32336-VA Lic 1044

     It's that time of year that requires home inspectors to enter the hottest part of the home...the Attic space.

     And a good number of attics are not vented. Venting of attics is not only important to reduce energy consumption and the associated costs of heating and, mainly summer cooling, but having attic air flow also protects the attic and roof materials from deterioration and in some cases premature failure. Some of the sealed attics we've seen have roof sheathing (the wood supporting the shingles) that has been overheated for so long that the glue in the plywood or OSB (glued fiber board) has broken down so much that the wood begins to peel and flake off. In some cases, the wood is so weak that it is potentially dangerous to walk on the roof surface, as there is no longer structural support. And overheating solid wood rafters, beams, and other supporting members will cause them to discolor, and even loose their strength over time, and become more flammable if a fire were ever to occur. 

     In these homes, we note that deficiency in the inspection report with the statement that the next roof replacement will cost significantly more since the sub-surface wood sheathing will have to be replaced as well. And just hope a heavy tree limb does not fall on the roof before it is next replaced.

     So a vented atic is a cool and happy attic.

High Attic Temperature        

 Some design information can be found by clicking Here.

Comments (18)

William Feela
Realtor, Whispering Pines Realty 651-674-5999 No.

I know many people who think tha the attie shoudl be warm n the winter

Jun 20, 2018 02:55 PM
Donald A. Masters


When I was growing up, my dad would seal the attic gable vents in the winter with plastic to keep the attic warmer by reducing the cold winter air flow through the vents.  We had the typical minimal ceiling insulation so I'm sure it helped with heating costs in the winter.

     So the standard comment "it depends" also can be applied with this concept. In older homes that do not have a problem generating ice dams on the bottom edge of the roof, this would not be a problem to seal an uninsulated attic space in the winter.

     But if the home is in a colder climate (such as Minnesota) where the home typically generates ice dams, then the attic should be kept as cold as the outdoor air so that it does not assist in melting roof snow from the inside out, with the warmer attic air.

     In more recent homes, we typically have much more insulation over the top floor ceiling, and in some cases now, the attic is fully insulated and is a conditioned usable space. Even more recent, the roof is insulated above the cathedral ceiling or above the roof sheating, so all ventilation concepts have to be engineered with different concepts.  So much fun...

Nov 12, 2018 11:02 AM
MichelleCherie Carr Crowe .Just Call. 408-252-8900
Get Results Team...Just Call (408) 252-8900! . DRE #00901962 . Licensed to Sell since 1985 . Altas Realty - San Jose, CA
Family Helping Families Buy & Sell Homes 40+ Years

We see a good number of attics are not vented enough or properly.

Jun 20, 2018 06:16 PM


Jun 07, 2020 03:21 PM


Jun 07, 2020 03:21 PM


Jun 29, 2020 10:11 PM


Jun 29, 2020 10:11 PM


Aug 29, 2020 05:27 AM


Aug 29, 2020 05:28 AM