Attic Insulation Ventilation Balance

Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Attic insulation ventilation balance.

For help achieving the right balance between ventilation and insulation in your charlotte area home please contact us at ross witmer. The balance of the required ventilation provided shall be located in the bottom one third of the attic space. If there s a vapor barrier beneath the insulation it can be 1 300. Calculate net free vent space.

Intake vents located at the lowest part of the roof under the eaves allow cool. Placing the fan on a timer helps you save energy. The modeled attic had gabled construction measured 50 by 27 feet with a 4 12 roof slope and had r 30 insulation in the ceiling. Once you ve decided which type is best for you examine the material options and prices to home in on the right product.

After successful completion the student should be able to perform an inspection of the attic insulation ventilation and interior of a residential property according to the internachi residential standards of practice. Where the location of wall or roof framing members conflicts with the installation of upper ventilators installation more than 3 feet 914 mm below the ridge or highest point of the space shall be permitted. Both can be added to uninsulated attics or layered over existing material. Loose fill or batt the common term for blanket insulation.

The potential problems vary with the type of exhaust vent being used. To keep the ventilation space clear above soffit vents special baffles need to be installed before the insulation goes in. Unfortunately too many houses have sufficient exhaust but inadequate intake. The general rule of thumb is to have at least one square foot of vent space for every 150 square feet of attic area.

Some homeowners also take the time to build walkways and or storage platforms in the attic prior to installing insulation. For comparison we also evaluated a sealed attic one without vents at the soffit or the ridge. This cools your hot attic by drawing in air from outside and pushing overheated air to the exterior. An attic fan is only recommended if your home is sealed off from the attic and the soffit vents are unobstructed.

Our experience dates back to 1945. Balanced soffit to ridge and unbalanced soffit to soffit only. A section of this book lists the particular parts of. In most cases the best type of attic insulation will be blown fiberglass or blown cellulose insulation.

We evaluated two ventilation schemes.