Unvented Attic Problems

Roof vents are for warmer climates.

Unvented attic problems.

Attic ventilation myths that are off the charts 1. When it s hot outside the sun beating down on the roof can increase the temperature in the attic. Unvented attics do not experience such problems. Unventilated attics can help to mitigate energy loss through leaky ducts or ceiling fittings.

An unvented attic is conditioned space and won t be subject to the extremes of temperature common to vented attics. However if moisture is able to enter the unvented attic space it may lead to roofing panel issues. The energy savings touted by unvented attics can be as high as 20. The intent of this brief is to provide code related information about controlling moisture in unvented attics by installing a vapor diffusion port vent that would convey water vapor from an unvented attic to the outside when air permeable insulation materials are installed and can be verified as being in compliance with the related codes and standards for residential construction.

Heat and moisture buildup in an attic cause predictable but different problems in hot and cold climates. More attic ventilation is good. Just like properly sizing your furnace and air conditioning unit you want precisely. Lots of gba readers have posted reports of this type of problem.

Here is a sampling. Unvented conditioned attics were quite rare before the 1980s. Too many people believe the importance of roof ventilation is to increase energy.