Venting Your Attic Space

If your attic covers the entire house a measurement of its outside dimensions will give you the area of the attic space.

Venting your attic space.

So if your attic is 25 by 15 you ll need 2 5 feet of vent space. Unless your roofing system has insulation on the roofing deck and is designed without ventilation your furnace should not be heating your attic. If the attic space is going to be conditioned either for living or mechanical purposes or if a home design calls for a vaulted ceiling provision r806 3 in the international residential code calls for the roof deck above the space to be vented continuously from the eave to the ridge. 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.

Here are four signs of an unventilated or under. Intake vents located at the lowest part of the roof under the eaves allow cool. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. Vent the roof deck.

An attic fan works by exchanging the hot air in your attic space for fresh air pulled through the vents. These fans may be controlled by a switch or a thermostat which detects heat build up in the attic space and automatically exhausts the attic space. If there are asphalt shingles on your roof the attic must be ventilated to comply with the terms of the manufacturer s warranty. Fans and vents may be installed on the roof system that will draw the air out of the attic space and exhaust it to the exterior.

Whole house fans powered attic fans. Poor insulation is usually the culprit although if you enter the attic on sunny winter day your attic space can be warmed by the sun more than your furnace. This will help to avoid premature damage to the shingles or mold building up in moist hot. In the summer good attic ventilation reduces heat buildup.

Your actual living space is sealed and insulated at the attic floor the attic is outside this envelope. Good ventilation allows the heat and moisture to escape. Then divide the total area by 150 to find the total amount of vent space needed for your attic. Don t avoid ventilating your attic for fear you re letting cold air into the house.

To choose the proper ventilation system for your attic you ll first need to know the total area of your attic. This is easy to accomplish in simply. The net free vent nfa area of each vent you have installed should be. To determine the area multiply the length times the width in feet.

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.