Too Much Roof Ventilation

Roof vents create an additional roof penetration essentially another place of vulnerability where leaks can occur.

Too much roof ventilation.

Before we explore how to ventilate an attic space it is prudent to understand how much ventilation is needed. 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. 2 focusing only on heat buildup. It s possible to have too much exhaust ventilation but you cannot have too much intake ventilation.

Enter square footage calculate or enter the square footage of the attic or area to be vented. One static vent style is the turbine vent. And when you put too many products on your roof that s improper ventilation. If there is more intake ventilation than the attic s square footage requires it s not problematic because any excess intake converts to exhaust on the leeward side of the house.

Beyond the decreased capacity for insulation when venting the roof deck venting the roof deck or the attic has some other drawbacks worth considering. Roof ventilation keeps the air moving and stops mold from growing but too much ventilation can be just as bad as having none. In cold climates snow can enter the soffit and ridge vents melt and potentially cause rot. If a roofing contractor is going to be out of balance with the attic ventilation system it s better to have too much intake than too much exhaust because the excess intake converts to exhaust on the leeward side of the house.

Some vents are necessary but you don t want to needlessly increase the number of roof penetrations. The two main dangers associated with too much ventilation involve roof damage and increased utility bills. Homeowners can choose from a variety of shapes and colors that closely match their shingles so that the vents won t appear too out of place on the roof. What happens is people put too many products on their roof.

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. However the same is not true when it comes to exhaust. If you have too much air circulating your roof will collect moisture causing damages that will weaken spots and then cause leaking. In no case should the amount of exhaust ventilation exceed the amount of intake ventilation.

Ventilation of attic spaces is required by most building codes as well as by roofing material manufacturers and the national roofing contractors association nrca. To be sure your roof is getting enough ventilation there are simple calculations that you can follow.