Converting Vented Attic To Unvented

Vented roofs serve a number of different purposes and their roles vary from climate to climate.

Converting vented attic to unvented.

A secondary goal is to vent moisture that infiltrates the attic from the conditioned home. From my research it looks like the best option is to make the attic a conditioned nonvented space. An unvented attic system relies on an air seal and no vents to make the attic a conditioned space. The loss of energy efficiency means some designers choose to move the ductwork into the conditioned areas of the home and leave the attics unvented.

Asked by gary lichtenstein. I ve been warned that closed cell foam can lead to sheathing rot from either roof leak or vapors from the house. Should i use open cell or closed cell foam to insulate. A 1 and story home with a room located in the attic and the thermal boundary located at either a the walls and ceiling of the attic room with small vented attic spaces or b the roof line for an unvented attic.

Poorly insulated ducting can cause heat loss in colder months and the loss of conditioned air in the summer in vented attics. I m considering converting my vented attic into a non vented conditioned space. I ve been researching several methods to insulate my attic. By using an air impermeable insulation like spray foam on the roof deck will stop any air movement.

I live in maryland and own a house that has the hvac system in the attic. Currently the attic is vented and has zero insulation anywhere. In colder climates the main purpose of a vented roof is to keep the roof cold and reduce the formation of ice dams. If you convert your vented unconditioned attic to an unvented conditioned attic by installing open cell spray foam on the underside of your roof sheathing you may be surprised to discover that your attic is now the most humid room in your house.

Converting an attic from vented to unvented can reduce utility costs while improving comfort indoor air quality and durability.