b'Steep SlopeContinued from page 29always go to ridge vents if the roofs design and theare compared to other categories of exhaust when attics size allows for a ridge vent application. Foryou enough intake, says Bellis. When the wind kicks good reasons. in and hits the vents external baffle, it absolutely Only ridge vents deliver a continuous flow of airamplifies the amount of exhaust. You cant get that because they are the only exhaust vent installedwith the other categories.interruption-free along the entire horizontal peak ofKey Point #4: Do Not Mix Exhaust Vent Typesthe roof. Every other category of exhaust is spacedIts never a good idea to combine two different types apart along the roof leaving pockets or gaps whereof attic exhaust vents on the same roof above a airflow is either skipped or reduced. As a result, ridgecommon attic. It leads to short-circuiting the system. vents are the only exhaust vent that fully vents the entire underside of the roof deck from low- to-highSometimes homeowners complain that the existing in the attic. exhaust vents are not performing well so they would like to give them a boost by adding another type; for example, adding box vents to a roof with ridge vents already installed; or adding a power fan to a roof with wind turbines already installed. Unfortunately, one type will be the primary exhaust vent while the second type could turn into the intake ventbringing in air and weather along the way. Air always follows the path of least resistance. When exhaust vent types are mixed on the same roof, the path of least resistance is the distance between the two types. It confuses the intended flow of air. It literally short-circuits the system.The condition of plywood on a room addition with plenty of attic insulation but zero ventilation; photo courtesy of Epic Exteriors. Mixing exhaust is extremely common, way more Cosmetically, because ridge vents are so low-profilecommon than you would think, says Bellis. I call with matching shingles installed on top, they are justthis situation an attic vent nightmare where we have about invisible from the ground looking up at the roof.ridge vent combined with power fan combined with Ridge vents blend in rather nicely with the beautybox vents combined with wind turbines. Sometimes of the roof compared to the other 4 categories ofits the homeowners fault. Sometimes its the roofing exhaust.contractors fault. Sometimes its both when the We always recommend to homeowners to go with ahomeowner talks the contractor into adding more ridge vent anytime their roof is a candidate. Its almostvents to try of alleviate problems the homeowner a no-brainer, says Bellis. Having installed ridgethought they had.vent now for 20+ years, weve seen the evolution ofBellis cautions, dont overlook the gable louvers, ridge vent design and performance come along. Andwhich are exhaust vents on the side of the house. installing it end-to-end on the roof helping it blendBlock off the gable louvers when using any other it with the roof is one of the signature looks wevetype of attic vent. Theyre sneaky little vents that you become known for. You simply cannot tell the roofmay not think can cause short-circuiting, he says. has exhaust vents on it. Key Point #5: Never Having it Before is Not One of the evolutionary features of ridge vents isa Reason to Skip it Nowthe external wind baffle. Its a lip or wing runningJust what does a roofing contractor say when the along the length of the ridge vent on both sides ofhomeowner says, I have never had proper attic the vent. It allows the wind to hit the vent, deflect upventilation before so why do I suddenly need it now? and over the vent and create low pressure aboveJust give me a new roof.the vent openings to enhance its exhaust airflowFor us, we install extended warranties for the roofs capabilities. It also deflects weather elements awaywe do. So, the shingle manufacturer is going to want from the vent and attic. us to fulfill their installation guidelines which includes Its amazing how much more effective ridge ventsproper attic ventilation, says Bellis. Then theres 30 www.mrca.orgMidwest Roofer'