How Much Roof Ventilation

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.

How much roof ventilation.

So much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus. The building code lets you reduce that by half under some conditions but more roof ventilation is usually better. If not measure the size yourself. Air vent 1320 cfm weatherwood galvanized steel electric power roof vent.

The open area of a vent is sometimes listed on the roof air vent as nfva net free vent area. Attic ventilation works on the principle that heated air naturally rises primarily utilizing two types of vents. 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. Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca.

The two main dangers associated with too much ventilation involve roof damage and increased utility bills. With a power switch or a thermostat installation an attic fan can be turned on to let hot air from the attic out. Intake vents located at the lowest part of the roof under the eaves allow cool. Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed.

Venting a homes attic is a very important best building practices will say 50 at the ridge and 50 at the soffits unobstructed. Then aim for about 1 sq. Roofing resources during covid 19 for contractors for homeowners. Dangers of too much ventilation.

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. 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. 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.

To keep air flowing your roof needs just the right amount of attic ventilation. Ventilation can be accomplished using various products and techniques.