Attic Ventilation Soffit Ridge Balance

Continuous or individual soffits.

Attic ventilation soffit ridge balance.

Soffit vents are one of the most popular intake vent styles. Attic ventilation soffit intake to ridge outlet air flow or square inches ratio. If the attic ventilation system is not a balanced combination of intake vents installed in the soffit under eave or at the roof s bottom edge and exhaust vents installed at or near the roof s peak the attic ventilation system will not be efficient and effective. Air pressure the thermal effect and diffusion.

Adding under roof ventilation is usually a great idea but if the relative sizes of the intake and outlet vents are not proper the building will suffer increased heat loss and thus an unnecessarily high home heating bill. Proper attic ventilation consists of a balance between air intake at your eaves soffits or fascias and air exhaust at or near your roof ridge. Soffit vents come in several sizes and styles including small round discs and rectangular grilles. 1 being out of balance.

Rafter vents or insulation baffles install in any rafter space to create narrow gaps that direct fresh air from the soffit vents to the peak of the roof. Basically for every square inch of ridge exhaust vent you must balance it with at least one square inch or more of soffit intake vent. Moisture in the attic can cause mold to grow and the wood can rot so air circulation is very important. Where the location of wall or roof framing members conflicts.

In addition insulation baffles must be installed at the point where the attic floor meets the roofline to prevent the attic insulation from migrating into the cavities and restricting the airflow from the soffit vents. Click to enlarge any image. Continuous ventilation systems with ridge and soffit vents keep attics dry. The soffit vents allow convective air movement from the soffits of the residence to the ridge vent.

These vents allow outside air to enter the attic at the lowest point of the roof along the underside of the eave. These specialty vents do not affect the. They are easy to install under the roof s overhang which is known as the soffit are generally hidden from sight and provide excellent protection from weather outdoor debris and pests while still allowing air to flow into the attic. Learn how to plan a continuous ridge and soffit ventilation system for your attic and how to install soffit vents and other attic venting systems.

They re most effective when used in conjunction with a continuous ridge vent. Outside air enters the attic space through soffit or eave vents rises through the attic space as it warms and exits through vents that are positioned at or near the top. Federal housing authority recommends a minimum of at least 1 square foot of attic ventilation evenly split between intake and exhaust for every 300 square feet of attic floor space.