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Roofing/Combining New Ridge Vents with Box Vents



My roof has inadequate ventilation.  The roof is 16 years old and 2 contractors have told me that the main body of the roof looks good and should have at least 10 years of life left.  There are box vents on the roof but not enough of them.  Is it OK to add ridge vents and combine them with the existing box vents?



Rooftime in Cincinnati is a 7 time Angie\'s List Supper Service Award Winner
Rooftime in Cincinnati  
I am sorry, but without seeing this actual roof for myself I cannot offer a definitive answer to the question.....I can tell you that todays best thinking on the subject is that it is not a good idea to mix two different types of exhaust ventilation as they can short circuit the design of air entry from a LOW or INTAKE point (usually vents in a soffit) to the HIGH / OUT-FLOW point.

I might also offer this, a well balanced ventilation system will have a design that has a 60-40 ratio of intake to exhaust. Most homes and many roof contractors seem to flip this formula for some reason.

Since you have had two roofers already investigate and offer a decade left assurance, and you still are seeking an answer, might I steer you to this site?  Visit,

There you can see many examples of poor and well ventilated roof systems and read the FAQ section about mixing exhaust and what their product experts think about it all!

Good Luck!



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Dale Rooftime Shoemaker


Follow us on TWITTER: search Dale Rooftime Follow us on FACEBOOK: search Dale Rooftime Shoemaker A residential roofing specialist. Owens Corning Preferred Contractor 2010-2012 Owens Corning Top Of The House Certified 2010-2012 Velux Skylights Certified Installer 2008-09. Box Gutter craftsman. Coppermsmith / Tinner. Certified EPA Asbestos Handler GAF Master Elite Contractor ELK 2006 Roofer of the Year / Midwest Region Owens Corning Preferred Contractor-1996 Certainteed Lifetime Wizard Certainteed Shingle Master Certainteed Quality Master Angie's List Super Service Award winner: 2006-2007-2008-2009 Press Community Paper, Cincinnati's Favorite Roofer 2009


A second generation roofer, working my son into the business now! We are certified FIBERGLASS insulation installers. We sell and install PINK FIBERGLASS loose-fill and Radiant Barriers. We are Cincinnati - Northern Kentucky's "GREEN" contrcator: recycling our waste material, lowering home energy costs, improving our world one job at a time!

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