Lstiburek Roof Venting

Vapor transmission of vent film needs to be higher than expected greater than 50 perms.

Lstiburek roof venting.

Roof slope is important. Lstiburek s rules for venting roofs. Historically roof assemblies have not contained enough insulation. Ventsure 4 foot strip heat moisture ridge vent.

The approach works for both cellulose and fiberglass in iecc climate zones 1 2 and 3 without limitation. Building scientist joseph lstiburek explains when to vent your roof when not to and how to execute each common roof venting approach successfully. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. 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.

27 lineal feet required. I live in new england where ice dams are a common problem which is to say improper roof venting is a common problem. Roof wrecking ice dams aren t the only reason to make sure a roof is properly vented of course. The usual exit points are at the ridge.

Joseph lstiburek s article a crash course in roof venting has a section that quickly explains why roof venting matters. In the moisture control handbook joe lstiburek explains why venting a roof may have worked better in the past. So heat loss from the conditioned space has warmed the attic area. Ordinary gable roofs don t have vents in the roof plane.

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. 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. 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. These are the soffit vents.

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. Joseph lstiburek talks about the not so controversial ways to maximize the efficiency and airflow of your roof and attic. It comes on an easy to install flexible mesh roll and is hand nailable with no complicated fitting wrapping nail gun adapters. The usual intakes are located in the soffit.

In iecc climate zones 4 and 5 some. These are the ridge vents.