Lstiburek Roof Venting

Building scientist joseph lstiburek explains when to vent your roof when not to and how to execute each common roof venting approach successfully.

Lstiburek roof venting.

Ventsure 4 foot strip heat moisture ridge vent. The intent of roof venting varies depending on climate but it is the same if you re venting the entire attic or if you re venting only the roof deck. Lstiburek s rules for venting roofs. I live in new england where ice dams are a common problem which is to say improper roof venting is a common problem.

Roof slope is important. Joe lstiburek notes that you can use gable vents instead of a ridge vent if you want but you still need soffit vents as air intake locations. The usual intakes are located in the soffit. Historically roof assemblies have not contained enough insulation.

In the moisture control handbook joe lstiburek explains why venting a roof may have worked better in the past. Vapor transmission of vent film needs to be higher than expected greater than 50 perms. Ordinary gable roofs don t have vents in the roof plane. Joseph lstiburek talks about the not so controversial ways to maximize the efficiency and airflow of your roof and attic.

In a cold climate the primary purpose of ventilation is to maintain a cold roof temperature to avoid ice dams created by melting snow and to vent any moisture that moves from the conditioned. Choose one of the following products to meet the recommended exhaust nfva of 528 square inches. These are the ridge vents. When installed as part of a properly balanced when installed as part of a properly balanced attic ventilation system gaf cobra exhaust vent is a shingle over exhaust vent installed at the roof ridge that helps exhaust excess heat and moisture from your attic.

27 lineal feet required. It comes on an easy to install flexible mesh roll and is hand nailable with no complicated fitting wrapping nail gun adapters. By joseph lstiburek issue 221 so much information has been devoted to the subject of roof venting that it s easy to become confused and to lose focus. In iecc climate zones 4 and 5 some.

The usual exit points are at the ridge. Roof wrecking ice dams aren t the only reason to make sure a roof is properly vented of course. So heat loss from the conditioned space has warmed the attic area. Theory behind venting the intent of roof venting var ies depending on climate but it is the same if you re venting the a crash course in roof venting by joseph lstiburek understand when to vent your roof when not to and how to execute each approach successfully roof venting 101 vent the attic space.

The approach works for both cellulose and fiberglass in iecc climate zones 1 2 and 3 without limitation. These are the soffit vents.