Roofing/Roof vents

Advertisement

Expert: Bruce A. Ryan II, RRO - 6/28/2009


Question
I own a home in Milwaukee, WI with a hip roof.  Would you recommend slant back vents over a ridge vent?  Thank you for your time.

Answer
Mike,

My answer depends on how much horizontal ridge you have at the peak of the roof and what the framing style is.  

A ventilation calculation must be performed and half of the required venting must be provided at the top of the passive venting system.  This requirement may not be met if your horizontal ridge is short.  Although you could install the ridge vent on all ridges including the hip ridges all the way to the gutter.  This will likely be supplemented with flanged style vents (slant back) at the lower portion of the roof unless you have soffit venting or plan to add it.

If your roof framing is achieved with trusses, then the ridge vent is most efficient and most aesthetic.  Also, if there is no attic space and the underside of the rafters are finished with a ceiling, then the flanged style vents need to be placed at the upper and lower portions of each joist space, so in this case the continuous ridge vents are the best when combined with soffit vents.

If the roof is conventionally framed, the roof sheathing has to be cut away enough to allow for a 1" gap on either side of the ridge beams and can result in nailing and support issues with the vent and shingles, so the flanged vents may be best with this condition.  

My experience has shown that there are more performance issues related to shingle over ridge vents than there are with flanged style vents.

I hope this helps you get to a conclusion,

Bruce Ryan II, RRO
Professional Roof Consultants, Inc.

Roofing

All Answers

Answers by Expert:

Ask Experts

Volunteer

Bruce A. Ryan II, RRO

Expertise

I offer solid knowlege of all types of Commercial and Residential Roofing, Waterproofing, and, Building Envelope systems. Experience ranges across low slope and steep slope roof systems. I am also well versed in matters regarding condensation and ventilation. I enjoy donating some of my time and knowledge to the betterment of others.

Experience

Bruce Ryan has 13 years of roofing, waterproofing, and building envelope consulting experience with PRC, with 5 years of commercial roofing experience prior to joining the firm. He became Vice President of the company in 1998. Bruce Ryan plays a key role in the development of practical, long-term roofing and waterproofing solutions, along with implementation of on-site forensic studies. Bruce also has a high level of experience with regard to the impacts of roofing materials and construction for demanding clients with heavily occupied structures.

Organizations
Oregon Construction Contractors Board Construction Specifiers Institute National Roofing Contractors Association The Institute of Roofing, Waterproofing, & Building Envelope Professionals Oregon Board of Investigators Installation Masters

Education/Credentials
University of Maryland BS Business & Administration Registered Roof Observer - RCI Private Investigator Certified EIFS inspector - Northwest Wall and Ceiling Bureau Certified InstallationMaster™ - The Installation Masters™ Training and Certification Program (developed by American Architectural Manufacturers Association)

©2012 About.com, a part of The New York Times Company. All rights reserved.