Not Enough Ventilation In Attic

If a bath fan dumps into the attic that is very warm very moist air entering a cold space.

Not enough ventilation in attic.

Attic ventilation only does an ok job removing moisture. If that air lingers it can cause condensation on the underside of the roof sheathing which can lead to wood rot and mold growth. Hot air fills the attic and raises the temperature. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents.

Once they are in place you can then place the batts or blankets or blow insulation right out to the very edge of the attic floor. Thick ridges of ice on your eaves in winter are a sign of poor attic ventilation. Snow melts and the water refreezes on the cold eaves creating ice dams. Rafter vents should be placed in your attic ceiling in between the rafters at the point where your attic ceiling meets your attic floor.

Just like properly sizing your furnace and air conditioning unit you want precisely the right amount of attic ventilation for your home. If the vents aren t supplying sufficient circulation the temperature in the attic can rise to 140 degrees fahrenheit or more on sunny days and that can significantly affect the climate in your. For instance in some places like las vegas the sun tends to set on the roof causing the attic to be warm. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

A hot ceiling tells you that the attic is acting like a solar oven raising your cooling bills and cooking the shingles. Intake vents located at the lowest part of the roof under the eaves allow cool. Most building codes require a ratio of 1 150 ventilation space to attic floor space. But in homes that do not have proper attic insulation or ventilation heat tends to migrate.

For example attic ventilation is used widely even in cold climates to evacuate the warm moist air that escapes from the living space below. You can also contact your local municipality to check on building code in your area. It s best to reduce how much gets there in the first place. Warm air that escapes rooms below gets trapped in the attic.

In most cases it is rare for the air in the attic to cool down at night. Insufficient ventilation can lead to moisture problems during the winter and decreased energy efficiency during the summer but too much ventilation can be just as bad if not worse.