How Much Roof Ventilation

Ventilation can be accomplished using various products and techniques.

How much roof ventilation.

The building code lets you reduce that by half under some conditions but more roof ventilation is usually better. As a certified licensed home inspector it is not correct to say too much ventilation is bad for an attic unless rain moisture is getting in. So i ll start by saying something that might sound controversial but really isn t. To keep air flowing your roof needs just the right amount of attic ventilation.

So much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus. In of vent opening per 150 sq. Let owens corning roofing help you calculate exactly how much ventilation you will need for a healthy and balanced attic with our 4 step ventilation calculator. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed.

The open area of a vent is sometimes listed on the roof air vent as nfva net free vent area. The two main dangers associated with too much ventilation involve roof damage and increased utility bills. Attic ventilation keeps the air moving and stops mold from growing but too much ventilation can be just as bad as having none. Then aim for about 1 sq.

A wind turbine catches the wind and spins a fan which pulls hot air outside. If not measure the size yourself. A vented attic where insulation is placed on an air sealed attic floor is one of the most underappreciated building assemblies that we have in the history of building science. Intake vents located at the lowest part of the roof under the eaves allow cool.

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. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. With a power switch or a thermostat installation an attic fan can be turned on to let hot air from the attic out. Dangers of too much ventilation.

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