Lstiburek Roof Venting

Historically roof assemblies have not contained enough insulation.

Lstiburek roof venting.

Choose one of the following products to meet the recommended exhaust nfva of 528 square inches. Ventsure 4 foot strip heat moisture ridge vent with weather protector moisture barrier. Vapor transmission of vent film needs to be higher than expected greater than 50 perms. Roof wrecking ice dams aren t the only reason to make sure a roof is properly vented of course.

Ventsure 4 foot strip heat moisture ridge vent. Joseph lstiburek s article a crash course in roof venting has a section that quickly explains why roof venting matters. The approach works for both cellulose and fiberglass in iecc climate zones 1 2 and 3 without limitation. It comes on an easy to install flexible mesh roll and is hand nailable with no complicated fitting wrapping nail gun adapters.

In iecc climate zones 4 and 5 some. The usual exit points are at the ridge. So heat loss from the conditioned space has warmed the attic area. 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.

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. In the moisture control handbook joe lstiburek explains why venting a roof may have worked better in the past. Roof slope is important. 27 lineal feet required.

Lstiburek s rules for venting roofs. 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. Building scientist joseph lstiburek explains when to vent your roof when not to and how to execute each common roof venting approach successfully. Climate limit is likely iecc climate zone 5 for new houses.

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. These are the ridge vents. 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.

The usual intakes are located in the soffit. I live in new england where ice dams are a common problem which is to say improper roof venting is a common problem.