Finished Attic Ventilation

To effectively ventilate your roof create a 1 in.

Finished attic ventilation.

Rafter vents should be placed in your attic ceiling in between the rafters at the point where your attic ceiling meets your attic floor. In cold climates the primary purpose of attic or roof ventilation is to maintain a cold roof temperature to control ice dams created by melting snow and to vent moisture that moves from the conditioned space to the attic ventilation acts to bypass the vapour barrier created by most roof membranes. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. Without properly ventilating the roof your finished space can be just as unpleasant as an unfinished attic.

That said air resistance and interference such as vent grates reduces the area of true ventilation. In a hot climate the primary purpose of ventilation is to expel solar heated hot air from the attic or roof to reduce the building s cooling load and to relieve the strain on air conditioning systems. Since parts of a finished attic are usually very close to the roof insulation often blocks proper ventilation that is needed under a roof structure. Flip the reverse switch in wintertime and it will push warmer air down to keep you cozy.

Insulate your finished attic properly choose your insulation. In other words the entire vent opening doesn t count as vented space. Install air chutes before installing insulation. If there are returns from the upper attic down to the hvac system check to make sure they are not closed off by a damper and that the hvac system is properly sized for the load as per manual j.

Intake vents located at the lowest part of the roof under the eaves allow cool air to enter the attic. Hot air exhaust vents located at the peak of the roof allow hot air to escape. If you ve got headroom a fan will make a finished attic more comfortable in warmer months by giving you a cool breeze indoors. Most building codes require a ratio of 1 150 ventilation space to attic floor space.

Without properly insulating your finished attic room will also be cold in the winter. In mixed climates ventilation serves either role depending on the season. If you re finishing your attic insulating it to the proper r value can cause a dramatic loss of. You can also contact your local municipality to check on building code in your area.

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